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Review

Environmental and Phytohormonal Factors Regulating Anthocyanin Biosynthesis in Fruits

by
Luodan Kuang
1,
Jiazhuo Chen
2,
Xiaoyu Bao
1,
Dong Zhang
1,
Jiaru Liu
1,
Wei Wang
1,
Yi Wei
1 and
Chengwen Zong
1,*
1
College of Agriculture, Yanbian University, Yanji 133000, China
2
College of Medical, Yanbian University, Yanji 133000, China
*
Author to whom correspondence should be addressed.
Horticulturae 2025, 11(6), 681; https://doi.org/10.3390/horticulturae11060681
Submission received: 23 April 2025 / Revised: 9 June 2025 / Accepted: 11 June 2025 / Published: 13 June 2025
(This article belongs to the Section Developmental Physiology, Biochemistry, and Molecular Biology)
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Abstract

Fruit color is a key indicator of appearance quality. Anthocyanins are flavonoids that not only give plants their rich colors but also contribute to human health due to their antioxidant properties, such as preventing cardiovascular disease. As a result, fruits with high anthocyanin content are becoming increasingly popular in the market. Anthocyanin biosynthesis is regulated by various genetic, developmental, and environmental factors, primarily through physiological and biochemical metabolism, as well as the expression of structural and regulatory genes. This review explores how environmental factors and phytohormones jointly regulate anthocyanin biosynthesis, thereby providing strategies to produce high quality fruits. Focusing on major environmental factors and hormonal signaling, this review summarizes current knowledge on the transcriptional networks that regulate anthocyanin biosynthesis, with particular emphasis on the crosstalk between these regulatory factors.

1. Introduction

Anthocyanins, a subclass of flavonoids, are natural water-soluble pigments responsible for red, blue, and purple coloration in leaves, flowers, and fruits. The color transitions during fruit ripening are primarily driven by chlorophyll degradation along with the accumulation of carotenoids and anthocyanins. Anthocyanins protect plants from biotic and abiotic stresses, attract pollinators, scavenge free radicals, and mitigate light stress [1,2,3]. Furthermore, anthocyanins exhibit significant nutraceutical effects in humans, including cancer prevention, anti-aging, antioxidant activity, enhancement of visual acuity, and vascular protection [4,5,6,7]. Consequently, fruits with elevated anthocyanin content are increasingly valued in the marketplace, meaning that anthocyanin concentration can often serve as a critical determinant of the value of fruit commodities.
Anthocyanin biosynthesis pathways constitute a branch of phenylpropanoid metabolism and involve a series of reactions catalyzed by key enzymes such as phenylalanine ammonialyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), flavanones 3-Hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanin synthase (ANS), and UDP-glucose: flavonoid 3-glucosyltransferase (UFGT) [8] (Figure 1). The transcriptional regulation of these genes is predominantly mediated by the MYB-bHLH-WD40 (MBW) protein complex, which plays a pivotal role in anthocyanin-characterized biosynthetic pathways [9,10]. Various MYB transcription factors have been identified as principal regulatory components with ubiquitous function in various fruits [11,12,13] (Figure 1). For instance, Jin et al. [14] described the pivotal role of PavMYB10.1 in the regulation of anthocyanin biosynthesis in sweet cherries. They demonstrated that allelic variation at this locus determines fruit color diversity by driving tissue-specific expression patterns and enabling the formation of a canonical MBW activation complex (with PavbHLH and PavWD40). This complex transcriptionally regulates the anthocyanin pathway-associated genes (PavANS and PavUFGT) through the AE-box (AGAAACAA). Beyond the MBW complex, other transcriptional regulators including NAC (e.g., NAM, ATAF1/2, CUC1/2, etc.), MADS-box, bZIP (basic leucine zipper), and WRKY family transcription factors have been implicated in anthocyanin biosynthesis in fruits [15,16,17,18].
In general, anthocyanin biosynthesis in fruits is regulated by a complex interplay of factors, including the fruit maturity stage; environmental conditions such as light, temperature, nutrients in case of deficiencies, and drought stress; and various phytohormone signaling pathways [19]. Recent studies have also indicated that phytohormones—especially abscisic acid (ABA), ethylene, methyl jasmonate (MeJA), and gibberellins (GAs)—can also significantly impact fruit anthocyanin biosynthesis in response to specific environmental stimuli [20,21,22] (Figure 1).
This review aims to elucidate the regulatory mechanisms by which environmental factors and phytohormones combine to influence anthocyanin biosynthesis in fruits. We place particular emphasis on the interplay between hormonal signaling and environmental factors during the regulation of anthocyanin accumulation. We aimed to provide a comprehensive analysis that contributes to a deeper understanding of the complex regulatory networks governing anthocyanin biosynthesis. This information provides theoretical guidance for improving anthocyanin accumulation in fruits, thereby cultivating brightly colored fruits that attract consumers and enhance marketability.

2. Environmental Factors

2.1. Light

External factors influence anthocyanin formation in apples by supplying substrates for controlled metabolic processes or by interfering with endogenous regulation; this fundamental mechanism is a light-dependent, phytochrome-mediated process that requires photosynthetic activity after the initial anthocyanin peak, coinciding with cell division [23]. Most fruits exhibit greater anthocyanin accumulation in response to increased light intensity, whereas fruits grown in shaded conditions are less pigmented. This phenomenon has led to the widespread adoption of horticultural practices for commercial fruit production, including the use of reflective groundcover plants and the development of fruit bagging techniques to optimize light exposure and thereby enhance anthocyanin accumulation [24,25,26].
The light spectrum affects anthocyanin biosynthesis in fruits. Exposure to broad light spectra leads to inconsistent anthocyanin accumulation [27,28]. Even the same light spectrum triggers varying anthocyanin responses among different cultivars of the same fruit species [29,30], necessitating the consideration of light spectrum and cultivar. Different light qualities also regulate anthocyanin biosynthesis by beginning different signal chains at specific photoreceptors, thereby influencing downstream transcriptional regulation. For instance, red light is known to activate the photosensitive pigments phytochrome A (PhyA) and phytochrome B (PhyB) [31], while blue light generates signals via a conserved CRY-COP1-HY5 pathway [32,33]. In addition, UV-B triggers an interaction between ELONGATED HYPOCOTYL 5 (HY5) and B-box zinc finger proteins (BBXs), together with the MBW protein complex and UV RESISTANCE LOCUS 8 (UVR8); this interaction regulates anthocyanin biosynthesis [34,35,36] (Figure 2). Under light conditions, photoreceptors inhibit the E3 ubiquitin ligase activity of CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1), thereby preventing ubiquitination and the subsequent degradation of target proteins. The stabilized ELONGATED HYPOCOTYL 5 (HY5) protein then directly activates anthocyanin structural genes or interacts with the MBW complex to increase transcriptional activation [37,38] (Figure 2). As a coactivator of HY5 that is active in the light signaling pathway, BBX is also involved in light-induced anthocyanin biosynthesis. For example, in red pear, proteins such as PpBBX16 and PpBBX18 combine with HY5 to form the PpBBX-PpHY5 complex; this activates PpMYB10 expression and promotes anthocyanin accumulation [39,40]. In contrast, PpBBX21 acts as a negative regulator by disrupting PpBBX18-PpHY5 interaction [40].
In light-independent signaling pathways, specific transcription factors such as WRKY and bZIP respond to light signals via light-responsive cis-elements present in their promoter regions, and they interact with the MBW complex to promote anthocyanin biosynthesis [41,42,43]. Furthermore, light-induced post-translational modifications also play crucial roles in this regulatory network. For example, in apple peel, light-activated MdMPK6 phosphorylates MdHY5, which enhances its DNA-binding affinity for target genes, ultimately promoting anthocyanin biosynthesis [44] (Figure 2). Reactive oxygen species (ROS) generated under light stress can also regulate anthocyanin accumulation. For instance, UV-B radiation stimulates anthocyanin biosynthesis in apple peel via activation of plasma membrane-localized NADPH oxidase, which generates ROS as secondary messengers in specific signaling cascades [45].

2.2. Temperature

Temperature regulation of anthocyanin biosynthesis in fruits exhibits complex patterns. Generally, low temperatures enhance anthocyanin accumulation, while high temperatures inhibit it [46,47]. Moreover, fruit anthocyanin content is affected by the dynamic balance between the degradation and biosynthesis of glucosamine. In plum trees exposed to high temperatures, enhanced respiration and ethylene biosynthesis are known to lead to increased expression of anthocyanin structural genes. However, a concomitant rise in hydrogen peroxide production catalyzes the enzymatic degradation of anthocyanin via vacuolar peroxidase activity [48]. Transcriptomic analyses across various fruits, including grape, apple, and pear, have identified several transcription factor families (e.g., WRKY, bZIP, and NAC) as potential regulators of high-temperature-mediated anthocyanin biosynthesis [49,50]. For example, VviPrx31 in grape peel and MdLBD37 in apple peel, both of which exhibit significant differential expression in response to high-temperature stress, have also been shown to negatively regulate both anthocyanin structural genes and biosynthesis [51,52] (Figure 2).
Postharvest low-temperature storage is a strategy used to delay fruit senescence while simultaneously inhibiting anthocyanin degradation and promoting anthocyanin accumulation [53,54]. Under cold stress, plants usually produce anthocyanin to scavenge ROS, thereby protecting fruit. In apple peel, the RRD-DME domain of MdROS1 directly binds to the promoters of both MdF3’H and MdUFGT, enhancing their methylation status and promoting anthocyanin biosynthesis [55]. Under low-temperature conditions, specific low-temperature cis-responsive elements present in MYB and bHLH transcription factors are activated, which also promotes anthocyanin accumulation. For example, consider the C-repeat binding factor/drought response element binding protein (CBF/DREB)-mediated cold signaling pathway, which has been extensively characterized. In litchi, LcDREB2C directly binds to the promoters of LcMYB1, LcCHI, and LcF3H. This finding establishes a molecular link between low-temperature stress and anthocyanin biosynthesis [56]. Similarly, in blood orange, CsERF054 and CsERF061 respond to low temperature by binding to the DRE/CRT cis-element of the CsRuby1 promoter, which upregulates anthocyanin-related gene expression [57]. Further upstream regulatory mechanisms have been elucidated by Huang et al. [58], who found that low temperatures induce the expression of PpZAT5 and PpBBX32. These subsequently activate the PpMYB10.1 promoter and lead to the formation of the PpZAT5-PpBBX32-PpMYB10.1 complex, which positively regulates anthocyanin biosynthesis. As demonstrated by Zhang et al. [59] in a study of red pear, the ZAT5 transcription factor exhibits light-dependent regulatory functions, with light-induced PpZAT5 causing repression of PpBBX18 expression, ultimately inhibiting anthocyanin biosynthesis.
Unlike other fruits, low temperatures are known to inhibit anthocyanin accumulation in strawberry [60]. This species-specific response is mediated by the MAPK3-ICE1-CBFs signaling pathway, in which low-temperature perception leads to the phosphorylation and activation of MAPK3 by SnRK2.6 and MKK4. Next, the MKK4-MAPK3 module catalyzes the phosphorylation of chalcone synthase 1 (CHS1), a rate-limiting enzyme in anthocyanin biosynthesis. It simultaneously upregulates the expression of the ubiquitination-related gene KFB1, thereby accelerating CHS1 degradation. In addition, both the MKK4-MAPK3 and SnRK2.6-MAPK3 modules phosphorylate the central anthocyanin regulator MYB10, thereby reducing its transcriptional activity. This dual regulatory mechanism, which involves both enzyme degradation and transcription factor inactivation, provides a molecular explanation for the unique temperature-dependent regulation of anthocyanin biosynthesis in strawberry. CRISPR-mediated knockout of FvMAPK3 reduces anthocyanin content in strawberry fruits under normal conditions while maintaining coloration under low-temperature stress, a finding with potential breeding value.

2.3. Mineral Nutrients

Mineral nutrients—especially nitrogen (N), phosphorus (P), and potassium (K)—play crucial roles in regulating plant growth and fruit pigmentation, with nitrogen being the most determinative element. Specific proteins are responsible for the absorption and transport of nitrate (NO3−) and ammonium (NH4+); these include RT1/2, NAR2, and AMT1/2. Compared with nitrate-N treatment, strawberry fruit anthocyanin increased under organic- and ammoniacal-N fertilization [61]. In apple peel, MdATG18a enhances nitrate absorption and assimilation by upregulating the nitrate reductase MdNIA2 and the high-affinity nitrate transporters MdNRT2.1/2.4/2.5. These effects cause improved tolerance of nitrogen deficiency and increasing anthocyanin accumulation via the upregulation of MdATG gene expression [62]. Furthermore, apple flesh exposed to low-nitrogen conditions induces the expression of MdMKK9, which subsequently upregulates both anthocyanin structural genes (i.e., MdCHI, MdF3H, MdANS, and MdUFGT) and transport genes (i.e., MdNRT2.7), both of which cause increased anthocyanin biosynthesis [63] (Figure 2). In addition, low nitrogen levels can also increase fruit anthocyanin accumulation; this occurs by increasing the expression of PyNAC42 in pear and reducing the expression of the inhibitory factor VvLBD39 in grape peel [64,65]. Conversely, sufficient nitrogen availability increases expression of the nitrate-responsive gene MdBT2, which recruits and degrades the MdMYB1 protein via the 26S proteasome pathway. This prevents MdMYB1 from binding to the Myb-binding site of downstream anthocyanin structural genes and inhibits their expression, thereby reducing anthocyanin accumulation in apple peel [66]. In addition, elevated nitrogen levels increase the transcription of the negative regulators MdLOB52 and MdARF19, both of which further suppress anthocyanin biosynthesis in apple flesh [67].
Phosphorus (P) is an essential macronutrient for plant growth and development and P-starvation usually results in anthocyanin accumulation [68,69]. For example, PHO2, a ubiquitin-conjugating E2 enzyme, serves as a key negative regulator of both phosphorus absorption and transportation. In strawberry, the Fvpho2 mutant not only shows higher soluble solid and phosphorus content but also contains higher anthocyanin content [70]. The gene PHR1 plays a key role in phosphate (PI) hunger reactions and in phosphorus-deficient plant anthocyanin biosynthesis. In apple peel, MdPHR1 interacts with MdWRKY75, a positive regulator of anthocyanin biosynthesis, to enhance the MdWRKY75-activated transcription of MdMYB1, leading to anthocyanin accumulation. Moreover, the protein kinase MdBIN2 phosphorylates MdPHR1 and positively regulates MdPHR1-mediated anthocyanin accumulation by attenuating the MdSINA1-mediated ubiquitination-based degradation of MdPHR1 [71] (Figure 2).
In grapes, the red color is concentrated in the peel, not the flesh (pericarp), in contrast to many other fruits. Potassium application can promote the accumulation of anthocyanins in grape fruit peels by regulating the upregulation of GST, AT, UFGT, SPS, HT, PK, and KUP gene expressions [72]. In blueberries, potassium treatment markedly enhances the activities of key enzymes (F3H, F3′5′H, and UFGT) involved in anthocyanin biosynthesis and K transporters (AKT1 and KUP) [73]. Fertilizers with different N:P:K ratios improve anthocyanin contents in fruits. Elevated K levels coupled with reduced P and N ratios more effectively promote fruit anthocyanin accumulation [74,75].

2.4. Drought and Salt Stress

In plants exposed to drought and salt stress, the addition of synthetic anthocyanin can effectively alleviate ROS accumulation, thereby improving plant stress resistance. For example, sweet potato drought and salt stress promote the expression of the protein IbMYC2, which interacts with IbCHI and IbDFR via a G-box response element and ultimately promotes anthocyanin biosynthesis [76]. In addition, when exposed to drought stress, MdERF38 interacts with MdMYB1, thereby facilitating the binding of MdMYB1 to its target genes MdDFR and MdUF3GT, also causing anthocyanin accumulation in apple peel. However, this process is negatively regulated by MdBT2, which ubiquitinates and degrades MdERF38; therefore, MdBT2 expression suppresses MdERF38-mediated anthocyanin biosynthesis [77]. In addition, the apple flesh transcription factor MdZAT5 has been found to directly or indirectly activate the expression of specific anthocyanin-related genes. This simultaneously increases anthocyanin accumulation and downregulates the expression of salt stress-related genes [78] (Figure 2). Taken together, these findings highlight the complex regulatory networks underlying anthocyanin biosynthesis in response to abiotic stress.
In addition to the environmental factors mentioned above, others elements also influence anthocyanin levels. For example, CO2 can inhibit the peak accumulation of anthocyanins during color change, thereby delaying ripening [79]. Conversely, H2S promotes anthocyanin accumulation and color development in grape peels. The in vivo accumulation of H2S is regulated by VvWRKY30, which promotes the expression of VvSiR, a gene encoding a synthetase [80].

3. Phytohormones

3.1. Abscisic Acid

Abscisic acid (ABA) plays an important role in many parts of the plant life cycle and is known to significantly influence both fruit ripening and anthocyanin biosynthesis [81,82]. During exocarp ripening, anthocyanin accumulation was higher in ‘Hass’ avocados than in ‘Fuerte’ avocados; ABA was involved in exocarp color formation and mesocarp softening in Hass avocados [83]. Most physiological processes mediated by ABA are predominantly modulated via regulation of its bioactive concentration, with 9-cis-epoxycarotenoid dioxygenase (NCED) serving as the critical rate-limiting enzyme involved in ABA biosynthesis. In sweet cherries, the transcript abundance of ABA biosynthesis-related genes (PavPSY, PavZEP, and PavNCED1) decreased sharply during the pink–red stage in bicolored ‘Royal Rainier’ cherries but increased in ‘Lapins,’ correlating with the elevated ABA content of this dark-red cultivar. Moreover, exogenous abscisic acid promotes the transcriptional activation of NCED, thereby facilitating an increase in ABA accumulation [84]. Accumulated ABA then stimulates the transcription of the MYB-bHLH-WD40 protein complex and upregulates the expression of anthocyanin-related genes, which in turn promotes anthocyanin accumulation and fruit coloration [85,86].
Plant cells first sense ABA but then facilitate its translocation into the cell to realize ABA function. For example, receptor proteins such as PYRABACTIN RESISTANCE1 (PYR1)/PYR1-LIKE (PYL)/REGULATORY COMPONENTS OF ABA RECEPTORS (RCAR) are all known to sense bound ABA. Moreover, high concentrations of ABA cannot reverse RNA interference (RNAi)-induced downregulation of FaPYR1 and inhibit red strawberry coloration [87]. Moreover, in grape skin, overexpression of the gene VlPYL1 has been found to enhance anthocyanin accumulation [88]. In general, both up- and downregulation of PYR/PYL/RCAR affect the expression of key genes such as sucrose nonfermenting 1-related subfamily2 protein kinases (SnRK2s), abscisic acid-insensitive family members (ABIs), and abscisic acid-responsive transcription factors (ABFs) [89]. For example, in the presence of ABA, the PYR/PYL/RCAR receptor protein stops the interaction between PP2Cs and SnRKY2s, causing SnRKY2s to be activated via autophosphorylation; this affects the expression of downstream ABA-responsive genes such as ABFs/AREBs and ABI5 [90]. Another study has shown that the ABA signal-responsive gene LcABF3 controls the expression of anthocyanin-related structural genes by binding to the AREB cis-element of LcMYB1, thereby promoting anthocyanin accumulation in litchi [91] (Figure 3). In apple peel, cherry, and blueberry, ABI5 binds to bZIP transcription factors to recognize the G-box site present on the promoters of MYB and bHLH genes. This activates their expression and thereby promotes the expression of downstream anthocyanin structural genes [92,93,94] In addition, ABA-dependent transcription requires NAC family transcription factors. For example, in apple flesh, the MdNAC1 promoter promotes the expression of MdMYB10 and MdUFGT. These proteins induce anthocyanin accumulation in apple flesh by forming a complex with MdbZIP23, which plays a role in ABA signaling [95]. In strawberry, the inhibition of MADS causes the upregulation of the anthocyanin-related genes PAL, C4H, 4CL and UFGT, thereby inhibiting anthocyanin biosynthesis. This occurs in the presence of ABA, ABI, and activated TRAB transcription factors and when miRNA529 directly inhibits MADS expression [96,97].
Furthermore, 13C and 15N double isotope labeling experiments showed that exogenous ABA coordinated the accumulation of carbon and nitrogen nutrients during the late stage of apple fruit development. This caused decreased accumulation of fruit nitrogen and an increase in the accumulation of fruit carbon and sugar, consequently providing substrates for the synthesis of anthocyanin during late apple fruit development. Moreover, ABA also promoted anthocyanin biosynthesis via sugar signaling regulation [98]. Taken together, these findings indicates that carbon and nitrogen nutrients, including sugar, can regulate anthocyanin biosynthesis via ABA. Further research is required to identify mechanisms that mediate the ABA response to external conditions and maintain plant anthocyanin homeostasis.

3.2. Ethylene

Fruit coloration is accompanied by ethylene release during the ripening phase of climacteric fruits. Previous studies have shown that ethylene induces anthocyanin biosynthesis in climacteric fruits such as apple [99] and plum [100]. In contrast, ethylene reduced the anthocyanin content in ‘Red Early Crisp’ pears (also climacteric) [101]. The ethylene biosynthesis pathway involves the conversion of methionine to S-adenosylmethionine (SAM) catalyzed by SAM synthetase, followed by the transformation of SAM to 1-aminocyclopropane-1-carboxylic acid (ACC) via ACC synthase (ACS). The final step is the oxidation of ACC to ethylene by ACC oxidase (ACO) [102,103]. Enhancement of the bioactivities of ACS and ACO in response to exogenous ethylene stimulated the release of endogenous ethylene and increased the expression of anthocyanin-related genes [104]. Conversely, in blueberry, microRNA-mediated regulation of ethylene biosynthesis genes via the VcMIR156a/VcSPL12 module is a novel mechanism involved in ethylene–anthocyanin crosstalk. Here, reduced VcACS1 and VcACO6 expression leads to decreased anthocyanin accumulation [105].
The ethylene signaling pathway, which is mediated via the ethylene receptors CONSTITUTIVE TRIPLE RESPONSE 1 (CTR1) and ETHYLENE INSENSITIVE 1/2 (EIN1/2), culminates in the stabilization of specific EIN3/EIL1 transcription factors that subsequently activate downstream transcription factors such as ERFs [106] (Figure 3). In apple peel, MdEIL1 directly binds to the MdMYB1 promoter and transcriptionally activates MdMYB1 expression, thereby leading to anthocyanin accumulation. MdMYB1 positively regulates the expression of MdMYB1 by binding to the MdERF3 promoter, a key regulatory factor involved in ethylene biosynthesis. Thus, MdEIL1, MdMYB1, and MdERF3 form a regulatory loop that synergistically regulates both ethylene biosynthesis and the accumulation of anthocyanins [99]. In red-skinned pear fruit, ethylene-activated PpERF105 induces the expression of the repressor PpMYB140, which inhibits anthocyanin biosynthesis [101]. Other studies in pear have shown that PyERF4.1 and PyERF4.2 interact with PyERF3 via EAR motifs; this interaction leads to a decrease in the stability of the PybHLH3-PyMYB114-PyERF3 complex, which inhibits PyANS transcription [107] (Figure 3). Interestingly, MYB proteins containing the R2R3-MYB domain regulate anthocyanin biosynthesis and are classified into distinct subgroups (SGs) that control different biological functions. The corresponding MYB genes and their upstream regulatory factors may be the main contributors to the variation in ethylene-responsive pigmentation patterns between apple and pear. Moreover, the ethylene-induced upregulation of FcMADS9 shown in Figure 3 is positively correlated with anthocyanin accumulation [108].
Although elevated ethylene production is a characteristic of climacteric fruits, recent studies have shown that ethylene treatment promotes anthocyanin accumulation in nonclimacteric fruits [109,110]. The effect of ethylene on anthocyanin dynamics in strawberries depends on the developmental stage; ethylene-treated samples exhibited a 25% higher total anthocyanin content at the white stage than controls, with no significant differences during the green, pink, and red developmental phases [111]. Overall, the phenotypic consequences of exogenous ethylene treatment on fruit quality are cultivar- and maturity-dependent, requiring case-specific analysis to determine its promotive or inhibitory effects.

3.3. Jasmonate

MeJA is another phytohormone that is involved in many plant development processes, including leaf senescence, secondary metabolite biosynthesis, and sugar transport. Jasmonates (Jas) are synthesized from a-linolenic acid via the octadecane pathway, which involves a variety of enzymes including lipoxygenase (LOX), polypropylene synthase (AOS), and 12-oxophytodienoate reductase 3 (OPR3). In peach fruit, MeJA has been found to induce changes in the expression profiles of the genes PpLOX, PpAOS, and PpOPR3, leading to JA accumulation. Jas also increased the expression levels of the anthocyanin-related genes PpMYB, PpPAL, PpCHS, PpCHI, PpF3H, PpDFR, and PpUFGT, thereby promoting anthocyanin accumulation in peach fruit [112]. Since MeJA can promote the expression of structural genes involved in anthocyanin biosynthesis, treating peach fruits with MeJA prior to harvest can promote the accumulation of anthocyanins in peach fruits during storage [113].
MeJA mainly transmits signals downstream via a specific jasmine signal transition route; this helps to adjust anthocyanin accumulation within the fruit. Moreover, in Arabidopsis and strawberry, the JAZ protein has been shown to inhibit the formation of the MBW complex via specialized interactions with bHLH and MYB, thereby inhibiting the expression of anthocyanin-related genes. However, after receiving jasmine signals, the JAZ protein is degraded by COI-generalized degradation. This promotes bHLH and MYB transcription factors and facilitates re-formation of a stable MBW complex, thereby promoting anthocyanin accumulation [114,115]. In apple peel, MdTRB1 interacts with MdMYB9 to promote anthocyanin accumulation, but the JA signal inhibitor MdJAZ1 interacts with the protein MdTRB1 to interfere with MdTRB1′s ability to interact with MdMYB9, thereby negatively regulating anthocyanin biosynthesis [116,117] (Figure 3). In grape peel, MeJA can regulate the VvmiR156-VvSPL9 module during the early stages of color conversion to promote anthocyanin accumulation [118].
Overall, MeJA can induce ethylene production and ethylene signal transformation via EIN3/EIL1, and ethylene inhibits the expression of PpMYB10 and PpMYB114 by specifically blocking factors such as ERF, MYB, and bHLH transcription factors, ultimately causing the suppression of anthocyanin biosynthesis [119]. In apple peel, MeJAZ degrades MdJAZ5/10, whereas MdERF1B increases MdMYC2 and MdMYB1/9/11 promoter activity, thereby promoting anthocyanin accumulation [120].

3.4. Gibberellins

Gibberellin (GA or gibberellic acid) is widely present in nature and is known to promote plant growth and cell division. However, it also inhibits anthocyanin biosynthesis and degradation. In litchi, GA application can suppress anthocyanin biosynthesis and reduce pericarp browning [121]. In cells, GA homeostasis requires specific “activating enzymes” and “inactivating enzymes” to finely adjust GA biosynthesis and catabolism. GA3 oxidase (GA3oxs) and GA20-oxidase (GA20oxs) are two activating enzymes responsible for the biosynthesis of biologically active GA4, and the main degradation pathway of GA is catalyzed by the inactivation enzyme GA2-oxidase (GA2ox) [122]. In pear, PbGA2ox8 has been found to hydroxylate GA12 and GA53 into inactive Gas, thereby reducing GA4 levels and promoting the expression of PbMYB10 and PbUFGT, resulting in anthocyanin accumulation [123]. In gibberellin-mediated anthocyanin biosynthesis in apple peel, MdRGL2a promotes anthocyanin biosynthesis by facilitating specific interactions between MdTCP46 and MdMYB1 [124]. A further study on the role MdRGL2a plays in gibberellin-mediated apple anthocyanin biosynthesis found that GA induces the expression of SINA1, SINA2, and MYB308 [125]. In general, SINA1 mediates the ubiquitination and degradation of RGL2a, whereas SINA2 mediates the ubiquitination and degradation of CIPK20. In addition, MYB308 negatively regulates anthocyanin biosynthesis by competing with MYB1 for binding to bHLH3/33. However, when GA is absent, RGL2a interacts with WRKY75 to enhance the WRKY75-activated transcription of MYB1. Furthermore, RGL2a interacts with MYB308 to release bHLH3/33. The MYB1-bHLH3/33 complex then readily forms, thereby inducing the transcription of anthocyanin biosynthetic genes and promoting anthocyanin accumulation. In addition, CIPK20 expression is induced in the absence of GA, and CIPK20 phosphorylation of RGL2a can increase the stability of the RGL2a protein, which also promotes anthocyanin accumulation by interfering with the ubiquitination and degradation of RGL2a by SINA1 (Figure 3).
In addition, An et al. [126] reported that MdRGL2a can separate MdbHLH162 from the MdbHLH162-MdbHLH3/33 complex and that MdJAZ1/2 both interfere with interactions between MdRGL2a and MdbHLH162 by hindering formation of the MdRGL2a-MdbHLH162 complex. Through this pathway, JA alleviates the inhibitory effect exerted by GA on anthocyanin accumulation in apple peels. In a more in-depth study, Ji et al. [127] found that MdJAZ2 inhibits anthocyanin biosynthesis by suppressing the MdZFP7-mediated transcriptional activation of MdMYB1 and interfering in its interaction with MdWRKY6. In contrast, MdRGL3a reverses this effect by dissociating the MdJAZ2–MdZFP7 complex. Concurrently, the E3 ubiquitin ligase MdBRG3, antagonistically regulated by JA and GA, targets MdZFP7 for degradation. This mechanism shifts hormone signaling crosstalk from transcriptional regulation to post-translational modification. In sweet cherries, combined GA3 and homobrassinolide treatment improved fruit anthocyanin content [128].

3.5. Auxin

Auxin may negatively regulate anthocyanin biosynthesis in plants. For example, 2,4-D (2,4-dichlorophenoxyacetic acid) or NAA treatment has been found to inhibit anthocyanin-related gene expression and anthocyanin accumulation in raspberry [129]. To investigate the specific mechanisms by which auxin regulates anthocyanin accumulation, transcriptome sequencing and differential expression analysis were performed in wounded apple flesh tissues treated with high concentrations of NAA and 2,4-D. These tests helped to identify the repressor transcription factor MdARF2 as being significantly associated with anthocyanin inhibition [130]. Subsequent reports found that in the presence of exogenous auxin, MdIAA121 is degraded. This causes the release of MdARF13, which inhibits anthocyanin accumulation in apple flesh by binding to the MdDFR promoter [131]. Further research on the auxin-regulated anthocyanin accumulation network by Li et al. [132] found that the E3 ubiquitination ligase MdSINA4 promoted the ubiquitination and degradation of MdSINA11 and MdIAA29 as well as the release of MdARF5-1, thereby promoting transcriptional repression of MdERF3 by MdARF5-1 and reducing anthocyanin biosynthesis (Figure 3).
A recent study found that sweet cherries treated with the synthetic auxin 1-naphthylacetic acid (NAA) showed increased anthocyanin accumulation during fruit development, possibly via regulatory pathways involving ethylene and ABA metabolism [133]. Furthermore, receptor-like kinases and ubiquitin ligases responded to IAA and ABA, suggesting that they play pivotal roles in the signaling pathways of both hormones and may serve as key points of crosstalk in postharvest strawberry fruits [134]. This finding suggests that auxin may interact with other signals to regulate anthocyanin biosynthesis, and further studies should focus on mechanisms by which auxin interacts with other phytohormone signals to regulate anthocyanin homeostasis.

3.6. Cytokinin

Cytokinin affects the expression of anthocyanin structural genes and the activity of the MBW complex. For example, exogenous cytokinin treatment of apple flesh significantly increased the expression of MdDFR, MdUFGT, MdMYB10, and MdbHLH3 but inhibited the expression of MdMYBL2 and MdMYB305, two transcription factors known to inhibit anthocyanin accumulation [135]. Cytokinin response factors (CRFs) are key regulators involved in the cytokinin signaling pathway. One CRF in apple, MdCRF6, can inhibit anthocyanin biosynthesis by binding to the promoters of anthocyanin structural genes [136]. In addition, type B response regulators have also been found to play an important role in cytokinin signal transduction to regulate anthocyanin biosynthesis. In banana, analysis of PpRR transcription levels showed that B-PpRR mediated anthocyanin accumulation and that MaRR_B9 and MaRR_B12 interacted with the promoters of MaDFR and MaANS to repress their expression, thereby reducing anthocyanin accumulation [137,138] (Figure 3). These results show that cytokinin may regulate anthocyanin biosynthesis differently in different plant species.
Combined treatment with auxin and cytokinin (i.e., BAP or TDZ) has been found to significantly enhance cytokinin-induced increases in apple flesh anthocyanin content, but excessive auxin concentrations strongly inhibit anthocyanin biosynthesis, even in the presence of cytokinin [139]. In litchi fruit ripening, cytokinin and ABA have been found to have both cooperative and antagonistic effects [140]. Moreover, cytokinin may interact with other hormonal and non-hormonal signals to regulate anthocyanin biosynthesis. Further research should focus on how cytokinin interacts with these signals to regulate anthocyanin biosynthesis in response to stress conditions.

4. Interactions Between Environmental Factors and Phytohormones

Phytohormones serve as critical signaling molecules plants use to mitigate abiotic and biotic stresses, including ultraviolet (UV) radiation, low-temperature (cold) stress, high-temperature (heat) stress, and drought. Under stress conditions, phytohormones orchestrate complex physiological and molecular responses that enable plants to adapt to adverse environments. Transcriptional regulators, including transcription factors and co-regulators, function as pivotal intermediaries that integrate environmental signals with hormonal biosynthesis and signaling pathways. This regulatory nexus provides an integrated mechanistic basis for the observed regulation of anthocyanin biosynthesis in fruits exposed to stress conditions, as summarized in Table 1.

4.1. Light and Temperature

In postharvest pear fruit exposed to UV-B/visible light, high temperatures (27 °C) induced anthocyanin biosynthesis more effectively than low temperatures (17 °C). They did so by upregulating the expression of PyMYB10 and anthocyanin structural genes such as PpCHS, PpDFR, and PpUFGT [141]. In apple peel, the transcription factor MdCOL4 negatively regulates anthocyanin biosynthesis by interacting with MdHY5 to coordinate the expression of MdMYB1. Moreover, MdCOL4 directly binds to the promoters of MdANS and MdUFGT to repress their expression. High-temperature stress induces the expression of MdHSF3b and MdHSF4a; their proteins bind to heat shock elements within MdCOL4, thereby activating its expression. Conversely, in apple fruit peel, UV-B represses MdCOL4 expression, thereby mitigating the negative regulatory effect of high temperatures on anthocyanin accumulation [142].
In addition to visible light, UV-B has been found to interact with low-temperature stress and affect the regulation of anthocyanin biosynthesis [143]. For instance, MdBBX20 responds to low temperatures by becoming involved with MdbHLH3, which directly binds to low-temperature-responsive cis-elements within the MdBBX20 promoter. Once expressed, MdBBX20 subsequently interacts with MdHY5 to promote the expression of MdMYB1. It also binds to the promoters of downstream structural genes involved in anthocyanin synthesis [35].
Under the light–temperature co-regulatory mechanism governing anthocyanin accumulation in fruits, compensatory light exposure at suboptimal temperatures can effectively enhance anthocyanin biosynthesis. For instance, nocturnal LED-based illumination using blue or red light at reduced ambient temperature upregulates the expression of anthocyanin biosynthesis-associated genes, particularly accelerating pigment accumulation in grape berry skins during fruit maturation [144]. During the postharvest storage of apples, maintaining appropriate temperatures and supplementing with blue light can improve the anthocyanin content in apple peels, thereby enhancing their marketability [145].

4.2. Light and Phytohormones

Phytohormone levels are known to undergo significant changes in response to light radiation treatment. Hormonal signals then regulate anthocyanin biosynthesis via phytohormone-specific signaling networks. One study reported that visible light regulates the transport of malate from chloroplasts to mitochondria via malate dehydrogenase (MDH), and a reducing equivalent is then transported from chloroplasts to mitochondria through respiration. There, it serves as a substrate for ethylene synthesis, and the accumulated ethylene then regulates anthocyanin biosynthesis [146]. In apple peel, increased quantities of the long noncoding RNA (lncRNA) MdLNC610 under high-light conditions has been found to upregulate MdACO1 expression; this leads to ethylene biosynthesis and in turn promotes anthocyanin accumulation [147]. In addition to ethylene, ABA is another critical phytohormone involved in light-mediated anthocyanin biosynthesis. In sweet cherry exposed to specific light conditions, PavBBX6/9 activates PavNCED1 expression to promote ABA biosynthesis, and the resulting increased ABA levels enhance anthocyanin accumulation [148]. However, in strawberry, light and ABA independently regulate anthocyanin biosynthesis via activation of FaMYB10 expression [149]. Jasmonic acid is another phytohormone that integrates light signals with anthocyanin biosynthesis. During apple fruit ripening, JA production induces MdJAZ2 degradation and MdWER transcription, while light induces the expression of MdERF109. MdWER then interacts with MdERF109 to increase the transcription of MdCHS, MdUFGT, and MdbHLH3, which in turn promotes anthocyanin biosynthesis [21].
Overall, key phytohormones such as ethylene, ABA, and JA act as central mediators, and they integrate light signals with the expression of structural and regulatory genes via the anthocyanin biosynthetic pathway. Future research should focus on unraveling the molecular mechanisms that underly the crosstalk between these regulatory layers.

4.3. Temperature and Phytohormones

High temperatures induce the expression of CYP707A and AOG, whose proteins catabolize and inactivate ABA. This leads to a decrease in ABA levels and ultimately slows the rate of sweet cherry coloring [150]. Moreover, high-temperature stress directly suppresses the expression of anthocyanin biosynthesis-related genes by decreasing the stability and transcriptional activity of VvFHY3, which is further inhibited by VvARF3. Simultaneously, the reduced activity of VvFHY3 enhances its VvbZIP17 suppressive activity, triggering an excessive activation of the unfolded protein response. These dual inhibitory mechanisms synergistically diminish anthocyanin biosynthesis in grape peels [151]. In grape peels, high-temperature-induced expression of VvMYB44-1, a transcriptional repressor harboring an EAR motif, indirectly suppresses anthocyanin biosynthesis by upregulating the cytokinin biosynthesis-related gene VvLOG8 and repressing the cytokinin degradation-associated gene VvCKX4, thereby promoting cytokinin accumulation [152].
Exogenous GA3 (the active form of gibberellin) significantly reduces low-temperature-induced anthocyanin accumulation, whereas paclobutrazol, an inhibitor of gibberellin biosynthesis, conversely increases anthocyanin levels. Under low-temperature conditions, the expression of GA2ox1 increases, leading to a reduction in endogenous active gibberellins and the accumulation of DELLA proteins. This in turn enhances the transcriptional activity of HY5 and HYH on DFR expression [153]. In response to cold stress, DELLA proteins accumulate as gibberellins decrease; therefore, cold-induced anthocyanin accumulation may be explained as a decrease in gibberellin signaling. Ethylene, another key phytohormone, also responds to low-temperature stress and regulates anthocyanin biosynthesis. In postharvest plum stored either at 0 °C for 28 days or at 5 °C for 14 days, rapid anthocyanin accumulation in fruit flesh was accompanied by ethylene production. Subsequent analyses showed that PsERF1B interacted with PsMYB10.1 and PsbHLH3 to jointly promote PsUFGT, thus leading to anthocyanin accumulation [154,155]. During low-temperature storage, ethephon application can increase anthocyanin content in blood orange fruits [156]. In addition, MeJA has been found to enhance plant antioxidant capacity and thereby promote anthocyanin accumulation under cold stress [157]. Another study by Huang et al. [58] found that endogenous MeJA levels in peach are influenced by storage temperature and fruit tissue type. This suggested that JAs function upstream of the transcription factors PpBBX32 and PpZAT5 to induce anthocyanin accumulation at low temperatures.
In summary, the regulation of anthocyanin biosynthesis under temperature stress involves a complex interplay of hormonal signaling pathways, including ABA, GA, ethylene, and JA. In strawberry, the preharvest application of SA, ABA, and MeJA could be used to improve anthocyanin content in strawberry fruits during refrigerated storage [158].

4.4. Drought, Low-Nitrogen Stress, and Phytohormones

Auxin significantly inhibits anthocyanin biosynthesis by suppressing the expression of anthocyanin-regulated genes (i.e., MdMYB10 and MdbHLH3) as well as structural genes involved in the anthocyanin pathway. In contrast, nitrogen deficiency reverses the inhibitory effect of auxin on anthocyanin biosynthesis [139]. Furthermore, a recent study has shown that Repressor of GA1-3 (RGA) and GA-Insensitive can both enhance the transcriptional activity of Production of Anthocyanin Pigment 1 (PAP1) on various downstream genes. This is direct evidence that a known regulatory transcription factor is positively involved in anthocyanin biosynthesis [22]. This suggests that gibberellin (GA) signaling, via its interactions with DELLA proteins, may also play a role in integrating low-nitrogen-induced anthocyanin biosynthesis with PAP1 expression.
In grape peel, drought stress has been observed to enhance ABA levels. The ABA-signaling-regulated transcription factor VvAREB2 binds directly to the ABA-responsive element (ABRE) of the MIR156b promoter and activates miR156b expression. Furthermore, miR156b inhibits VvSBP8/13 expression, which disrupts the formation of the MBW transcriptional complex, leading to reduced anthocyanin content in grapes [159]. Therefore, spraying ABA under drought conditions may enhance the anthocyanin contents of fruits. For example, under semi-arid conditions, spraying ‘Wonderful’ pomegranate trees with 800 µg−1 mL ABA is recommended to increase aril coloration [160].
Table 1. Environmental factors associated with the regulation of fruit anthocyanin biosynthesis through phytohormones.
Table 1. Environmental factors associated with the regulation of fruit anthocyanin biosynthesis through phytohormones.
SpeciesEnvironmentPhytohormoneRegulatorsRegulated Genes/EnzymesAnthocyanin BiosynthesisReference
Apple (Malus domestica)LightEthyleneLNC610ACO1Inhibit[147]
LightJAERF109
WER		CHS, UFGT, bHLH3Promotion[21]
Light, Low TemperatureGAHY5DFRPromotion[153]
Plum (Prunus salicina Lindl.)Low TemperatureEthyleneERF1B, MYB10.1, bHLH3UFGTPromotion[155]
Peach (Prunus persica (L.) Batsch)Low TemperatureJABBX32, ZAT5MYB10.1Promotion[49]
Grapevine (Vitis vinifera)DroughtABAMYBA1, miR156b, SBP8/13MYC1, MYBA1, WD40Promotion[159]
High TemperatureABAVvARF3VvFHY3Inhibition[151]
High TemperatureCTKVvMYB44-1VvLOG8-
VvCKX4		Inhibition[152]
Sweet Cherry
(Prunus avium L.)		High TemperatureABA CYP707A, AOGPromotion[150]
Abbreviations: JA, jasmonic acid; GA, gibberellin, ABA, abscisic acid; CTK, cytokinin.

5. Conclusions and Outlook

Light supplementation, spectral modulation, low-temperature exposure, K-enriched NPK fertilization, and drought and salt stress enhance anthocyanin accumulation in fruits. The exogenous application of growth-promoting phytohormones generally inhibits anthocyanin biosynthesis, whereas senescence-associated phytohormones promote pigment production. Under adverse conditions, phytohormone supplementation can stimulate anthocyanin accumulation or maintain pigment levels. For instance, preharvest application of ABA, MeJA, and SA improves postharvest anthocyanin content in strawberry fruits. ABA treatment under semi-arid conditions induces aril coloration in pomegranates. The molecular mechanisms by which phytohormones and environmental factors regulate anthocyanin biosynthesis are being studied. On the one hand, core transcription factors associated with environmental cue-induced signaling pathways modulate anthocyanin synthesis by enhancing or disrupting the stability and function of the MBW complexes. On the other hand, phytohormones regulate anthocyanin synthesis through key transcription factors involved in signal transduction pathways, with crosstalk between various hormones. Beyond transcription regulation, recent studies have increasingly emphasized the important roles of post-translational modifications and epigenetics in the regulation of anthocyanin biosynthesis by environmental and phytohormones, such as ubiquitination, phosphorylation, long non-coding RNAs, and DNA methylation. Therefore, the molecular mechanisms of regulation among these factors, the synergistic or antagonistic regulatory relationships between transcription factors, and whether post-translational modifications exist in kinases and MBW complexes require further investigation. This is essential for refining the anthocyanin regulatory network, which holds significant implications for future applications of gene editing technology and the specific modification of transcriptional regulatory networks to enhance anthocyanin content in fruits.

Author Contributions

Writing—original draft, L.K.; Writing—review and editing, J.C., X.B., D.Z., J.L., W.W. and Y.W.; Writing—review and editing, Project administration, C.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by National Natural Science Foundation of China, grant number 32160690.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Anthocyanin synthesis via the phenylalanine pathway. Developmental and environmental factors can activate the MYB-bHLH-WD40 (MBW) complex, which regulates the transcription of structural anthocyanin biosynthesis-associated genes. Following the production of phenylalanine, the enzymes phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), flavonoid 3-hydroxylase (F3H), dihydroflavonoid 4-reductase (DFR), anthocyanin synthase (ANS), and glycosyltransferase (UFGT) catalyze anthocyanin biosynthesis.
Figure 1. Anthocyanin synthesis via the phenylalanine pathway. Developmental and environmental factors can activate the MYB-bHLH-WD40 (MBW) complex, which regulates the transcription of structural anthocyanin biosynthesis-associated genes. Following the production of phenylalanine, the enzymes phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), flavonoid 3-hydroxylase (F3H), dihydroflavonoid 4-reductase (DFR), anthocyanin synthase (ANS), and glycosyltransferase (UFGT) catalyze anthocyanin biosynthesis.
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Figure 2. Pathways by which environmental factors regulate anthocyanin biosynthesis in fruits. Light regulates anthocyanin synthesis via photoreceptors (e.g., PHY, CRY, and UVR8) involved in the COP1-HY5 pathway, as well as by a phosphorylation pathway involving the direct induction of other transcriptional regulators (e.g., WRKY, bZIP, BBX, etc.). Low temperatures regulate anthocyanin synthesis via CBF/DREB (C-Repeat/dehydration-responsive element binding factor) transcription factors as well as reactive oxygen species (ROS). Cold temperatures also inhibit anthocyanin and anthocyanin biosynthesis via phosphorylation. High-temperature conditions inhibit anthocyanin synthesis via the genes Prix and LBD. Studies of other transcription factors remain unverified. Nitrogen and phosphorus deficiencies promote anthocyanin synthesis via regulation of their uptake genes, whereas high nitrogen levels inhibit anthocyanin synthesis via specific transcription factors. Drought and salt stress are thought to promote anthocyanin synthesis via ERF and ZAT transcription factors, respectively. Black arrows indicate positive regulation and perpendicular lines indicate negative regulation.
Figure 2. Pathways by which environmental factors regulate anthocyanin biosynthesis in fruits. Light regulates anthocyanin synthesis via photoreceptors (e.g., PHY, CRY, and UVR8) involved in the COP1-HY5 pathway, as well as by a phosphorylation pathway involving the direct induction of other transcriptional regulators (e.g., WRKY, bZIP, BBX, etc.). Low temperatures regulate anthocyanin synthesis via CBF/DREB (C-Repeat/dehydration-responsive element binding factor) transcription factors as well as reactive oxygen species (ROS). Cold temperatures also inhibit anthocyanin and anthocyanin biosynthesis via phosphorylation. High-temperature conditions inhibit anthocyanin synthesis via the genes Prix and LBD. Studies of other transcription factors remain unverified. Nitrogen and phosphorus deficiencies promote anthocyanin synthesis via regulation of their uptake genes, whereas high nitrogen levels inhibit anthocyanin synthesis via specific transcription factors. Drought and salt stress are thought to promote anthocyanin synthesis via ERF and ZAT transcription factors, respectively. Black arrows indicate positive regulation and perpendicular lines indicate negative regulation.
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Figure 3. Pathways through which phytohormones regulate fruit anthocyanin biosynthesis. Phytohormones generally activate downstream response factors via specific transduction signaling pathways, which further regulate anthocyanin biosynthesis by interacting directly with anthocyanin-related genes. Black arrows indicate positive regulation and perpendicular lines indicate negative regulation.
Figure 3. Pathways through which phytohormones regulate fruit anthocyanin biosynthesis. Phytohormones generally activate downstream response factors via specific transduction signaling pathways, which further regulate anthocyanin biosynthesis by interacting directly with anthocyanin-related genes. Black arrows indicate positive regulation and perpendicular lines indicate negative regulation.
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MDPI and ACS Style

Kuang, L.; Chen, J.; Bao, X.; Zhang, D.; Liu, J.; Wang, W.; Wei, Y.; Zong, C. Environmental and Phytohormonal Factors Regulating Anthocyanin Biosynthesis in Fruits. Horticulturae 2025, 11, 681. https://doi.org/10.3390/horticulturae11060681

AMA Style

Kuang L, Chen J, Bao X, Zhang D, Liu J, Wang W, Wei Y, Zong C. Environmental and Phytohormonal Factors Regulating Anthocyanin Biosynthesis in Fruits. Horticulturae. 2025; 11(6):681. https://doi.org/10.3390/horticulturae11060681

Chicago/Turabian Style

Kuang, Luodan, Jiazhuo Chen, Xiaoyu Bao, Dong Zhang, Jiaru Liu, Wei Wang, Yi Wei, and Chengwen Zong. 2025. "Environmental and Phytohormonal Factors Regulating Anthocyanin Biosynthesis in Fruits" Horticulturae 11, no. 6: 681. https://doi.org/10.3390/horticulturae11060681

APA Style

Kuang, L., Chen, J., Bao, X., Zhang, D., Liu, J., Wang, W., Wei, Y., & Zong, C. (2025). Environmental and Phytohormonal Factors Regulating Anthocyanin Biosynthesis in Fruits. Horticulturae, 11(6), 681. https://doi.org/10.3390/horticulturae11060681

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