Search Results (54)

To explore the effects of various zinc (Zn) fertilizer application methods and concentrations on foxtail millet quality and flavonoid biosynthesis, we used Zhangzagu 13 as the experimental material. The transcriptome and metabolome were used to examine variations in flavonoid biosynthesis and metabolism in foxtail millet under different Zn application methods. The results showed that different Zn application methods significantly increased the total polyphenol, carotenoid, total flavonoid, and Zn contents in the grains of foxtail millet. Under the basal soil application (S3) and foliar spray (F2) treatments, the total flavonoid content significantly increased by 45.87% and 64.40%, respectively, compared with that of CK. Basal soil Zn fertilization increased the flavonoid content of foxtail millet by up-regulating genes related to flavonoid metabolism and biosynthesis, including flavanone-3-hydroxylase, chalcone isomerase, and leucoanthocyanidin reductase. Foliar Zn application enhanced flavonoid content by up-regulating genes involved in flavonoid metabolic and biosynthetic processes and chalcone isomerase. In conclusion, using Zn fertilizer can improve the synthesis and metabolism of foxtail millet flavonoids, effectively increase the content of functional substances in grains, and realize the biofortification of foxtail millet grains. Full article

The occurrence of anthocyanins in rice (Oryza sativa) and barley (Hordeum vulgare) varies among cultivars, with pigmented varieties (e.g., black rice and purple barley) accumulating higher concentrations due to genetic and environmental factors. The biosynthesis of anthocyanins is regulated by a complex network of structural and regulatory genes. Key enzymes in the pathway include chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), and UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT). These genes are tightly controlled by transcription factors (TFs) from the MYB, bHLH (basic helix–loop–helix), and WD40 repeat families, which form the MBW (MYB-bHLH-WD40) regulatory complex. In rice, OsMYB transcription factors such as OsMYB3, OsC1, and OsPL (Purple Leaf) interact with OsbHLH partners (e.g., OsB1, OsB2) to activate anthocyanin biosynthesis. Similarly, in barley, HvMYB genes (e.g., HvMYB10) coordinate with HvbHLH TFs to regulate pigment accumulation. Environmental cues, such as light, temperature, and nutrient availability, further modulate these TFs, influencing the production of anthocyanin. Understanding the genetic and molecular mechanisms behind the biosynthesis of anthocyanins in rice and barley provides opportunities for the development of biofortification strategies that enhance their nutritional value. Full article

Iris dichotoma Pall., renowned for its high ornamental value, is frequently cultivated in flowerbeds and courtyards, endowing garden landscapes with unique allure. Dark-hued flowers are widely regarded as more aesthetically appealing. This study utilized the petals of two distinct Iris dichotoma Pall. phenotypes as research materials to investigate the underlying mechanism of flower color formation. The purple-flowered Iris dichotoma Pall. was designated as Group P, and the white-flowered one as Group W. A comprehensive integrative analysis of the transcriptome and metabolome of the two petal types was carried out. Metabolomic analysis revealed that the contents of several anthocyanin derivatives, including delphinidin, petunidin, malvidin, peonidin, and procyanidin, were significantly higher in purple petals compared to white petals, with delphinidin exhibiting the highest content. The transcriptomic analysis detected 6731 differentially expressed genes (DEGs) between the white and purple petal types. Specifically, 3596 genes showed higher expression levels in purple petals, while 3135 genes exhibited lower expression levels in purple petals compared to white petals. Ten phenylalanine ammonia-lyase (PAL) genes, two chalcone synthase (CHS) genes, one anthocyanidin reductase (ANR) gene, one 4-coumarate-CoA ligase (4CL) gene, one dihydroflavonol 4-reductase (DFR) gene, one flavanone 3′-hydroxylase (F3′H) gene, and one flavonol synthase (FLS) gene were identified; they all had purple petals displaying higher expression levels than white petals. This research uncovers the potential formation mechanism of anthocyanins in the two Iris dichotoma Pall. types, thereby furnishing a theoretical foundation for floral breeding endeavors. Full article

The seed-coat color and seed size have an impact on both the evolutionary fitness and the grain yield of crops. Soybean is a major oil crop, and the seed-coat color and seed size exhibit natural diversity among the different soybean varieties. Here, we found an R2R3-MYB transcription factor of GmMYB62, which shows a significant increase in expression as the seed-coat color changes from yellow to black in different soybean varieties. The GmMYB62 was specifically highly expressed in reproductive organs, especially in floral organs in soybeans. The GmMYB62 encodes a nuclear protein that contains two MYB domains. In the phylogenetic analysis, the GmMYB62 was relatively conserved after the divergence of the monocots and dicots, and it also grouped with transcriptional repressors of MYBs in anthocyanin synthesis. The GmMYB62 was overexpressed in Arabidopsis and the seeds displayed a pale-brown coat in GmMYB62 overexpression lines, in contrast to the dark-brown seed coat observed in wild-type of Col-0. The anthocyanin content in the GmMYB62 overexpression lines was dramatically reduced when compared to Col-0. Additionally, the seeds in overexpression lines showed shorter lengths, larger widths, and lower thousand-seed weights than those in Col-0. Furthermore, the genes related to anthocyanin synthesis and seed size regulation were investigated, and expression of eight genes that involved in anthocyanin synthesis pathway, like chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), and anthocyanidin synthase (ANS) were severely inhibited in the GmMYB62 overexpression lines when compared to Col-0. In addition, the ARGOS-LIKE (ARL), B-Type Cyclin 1 (CYCB1), and enhancer of DA1-1 (EOD3), which govern cell expansion and proliferation, were highly expressed in GmMYB62 overexpression lines when compared to Col-0. Overall, this study sheds new light on the control of seed-coat color and seed size by GmMYB62 and provides potentially valuable targets for improving crop seed quality. Full article

Vegetative propagation of European grapevine (Vitis vinifera L.) requires grafting onto American rootstocks due to susceptibility to phylloxera. However, the grafting yield is compromised by the presence of grapevine trunk diseases (GTDs) such as Esca. This study investigates the phenolic response and enzyme activity in grapevine callus from grafts obtained by scions with different GTD status (healthy, asymptomatic, and symptomatic) treated with different disinfection methods (Beltanol, Beltanol in combination with thermotherapy, Serenade^® ASO, Remedier, BioAction ES, and sodium bicarbonate). Twenty-three phenolic compounds were identified in the graft callus, with flavanols, stilbenes, and condensed tannins predominating. Scion disinfection with BioAction ES led to a significant increase in total phenolic content in the callus, especially in symptomatic scions, for on average 510.3 µg/g fresh weight (FW) higher total phenolic content, compared to grafts where scions were treated with Beltanol. Phenolics such as epicatechin gallate, procyanidin derivatives, and resveratrol hexoside were significantly increased, indicating a strong elicitor effect of BioAction ES. Enzymatic activity analysis showed that the disinfection methods affected the activity of key enzymes involved in the phenylpropanoid metabolic pathway. In particular, BioAction ES significantly increased phenylalanine ammonia lyase (PAL) activity in callus from grafts with healthy scions by 3.4-fold and flavanone 3β-hydroxylase (FHT) activity in callus from grafts with infected scions by 4.9-fold (asymptomatic) and 6.9-fold (symptomatic) compared to callus from grafts with Beltanol-treated scions. The results highlight the potential of environmentally friendly disinfection methods, particularly BioAction ES, in influencing phenolic content and enzymatic activity in graft callus, potentially affecting the success of grapevine grafting. Full article

Drought stress significantly impairs the output of tea plants and the quality of tea products. Although Serendipita indica has demonstrated the ability to enhance drought tolerance in host plants, its impact on tea plants (Camellia sinensis) experiencing drought stress is unknown. This study assessed the response of tea plants by inoculating S. indica under drought conditions. Phenotypic and physiological analyses demonstrated that S. indica mitigated drought damage in tea plants by regulating osmotic equilibrium and antioxidant enzyme activity. Metabolome analysis showed that S. indica promoted the accumulation of flavonoid metabolites, including naringin, (-)-epiafzelechin, naringenin chalcone, and dihydromyricetin, while inhibiting the content of amino acids and derivatives, such as homoarginine, L-arginine, N6-acetyl-L-lysine, and N-palmitoylglycine, during water deficit. The expression patterns of S. indica-stimulated genes were investigated using transcriptome analysis. S. indica-induced drought-responsive genes involved in osmotic regulation, antioxidant protection, transcription factors, and signaling were identified and recognized as possibly significant in S. indica-mediated drought tolerance in tea plants. Particularly, the flavonoid biosynthesis pathway was identified from the metabolomic and transcriptomic analysis using Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Moreover, flavonoid biosynthesis-related genes were identified. S. indica-inoculation significantly upregulated the expression of cinnamate 4-hydroxylase (C4H), chalcone synthase (CHS), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanidin reductase (ANR), and leucoanthocyanidin reductase (LAR) genes compared to uninoculated plants subjected to water stress. Consequently, we concluded that S. indica inoculation primarily alleviates drought stress in tea plants by modulating the flavonoid biosynthesis pathway. These results will provide insights into the mechanisms of S. indica-enhanced drought tolerance in tea plants and establish a solid foundation for its application as a microbial agent in the management of drought in tea plants cultivation. Full article

Callus browning is a significant problem that hinders plant tissue regeneration in Paeonia ostii “Fengdan” by causing cell death and inhibiting growth. However, the molecular mechanism underlying callus browning in P. ostii remains unclear. In this study, we investigated the metabolites and potential regulatory genes involved in callus browning of P. ostii using metabolomic and transcriptomic analyses. We found a significant accumulation of phenolic compounds in the browned callus, represented by flavonoid compounds. Notably, the accumulations of luteotin and disomentin were higher in browning calli compared to non-browning calli. Transcriptomic analysis identified that candidate genes associated with flavonoid biosynthesis, including flavonoid 3-hydroxylase (PoF3H) and flavone synthase II (PoFNSII), were highly expressed in the browned callus of P. ostii “Fengdan”. Weighted gene co-expression network analysis (WGCNA) further highlighted that polyphenol oxidase (PoPPO) which encoded polyphenol oxidase, together with flavonoid biosynthesis-related genes such as flavanone 3-hydroxylase (PoF3H) and flavonone Synthase II (PoFNSII), as well as cellular totipotency-related genes wuschel-related homeobox 4 (PoWOX4), were involved in callus browning. Based on these findings, we proposed the molecular mechanism by which flavonoid accumulation, polyphenol oxidation, and cellular totipotency pathways contribute to callus browning in P. ostii. Our study provides new insights into the molecular mechanism underlying callus browning and offers the foundations to facilitate the establishment of an efficient plant tissue regeneration system in P. ostii. Full article

Pepper Phytophthora blight caused by Phytophthora capsici results in substantial losses in global pepper cultivation. The use of biocontrol agents with the dual functions of disease suppression and crop growth promotion is a green and sustainable way of managing this pathogen. In this study, six biocontrol strains of Trichoderma with high antagonistic activity against P. capsici were isolated and screened from the rhizosphere soil of healthy peppers undergoing long-term continuous cultivation. Morphological identification and molecular biological identification revealed that strains 2213 and 2221 were T. harzianum, strains 5111, 6311, and 6321 were T. brevicompactum, and strain 7111 was T. virens. The results showed that T. brevicompactum 6311 had the greatest inhibitory effect against P. capsici. The inhibition rate of 6311 on the mycelial growth of P. capsici was 82.22% in a double-culture test, whereas it reached 100% in a fermentation liquid culture test. Meanwhile, the pepper fruit tests showed that 6311 was 29% effective against P. capsici on pepper, and a potting test demonstrated that the preventive and controlling effect of 6311 on pepper epidemics triggered by P. capsici was 55.56%. The growth-promoting effect, germination potential, germination rate, radicle-embryonic axis length, germination index, and fresh weight of peppers cultured in the 6311 fermentation broth were significantly increased compared with the results for the control group. Scanning electron microscopy revealed that 6311 achieved the parasitism of P. capsici, producing siderophores and the growth hormone indoleacetic acid (IAA) to achieve disease-suppressive and growth-promoting functions. Transcriptomic results indicated that genes encoding proteins involved in plant disease resistance, namely flavanone 3-hydroxylase (F3H) and growth transcription factor (AUX22), were generally upregulated after the application of 6311. This study demonstrated that 6311 exhibits significant bioprotective and growth-promoting functions. Full article

Djulis (Chenopodium formosanum Koidz.), a member of the Amaranthaceae family plant, is noted for its vibrant appearance and significant ornamental value. However, the mechanisms underlying color variation in its spikes remain unexplored. This research initially detected the anthocyanin content at different developmental stages of the spike and subsequently utilized an integrative approach, combining targeted metabolomics, transcriptomics, and untargeted metabolomics analyses, to elucidate the mechanisms of anthocyanin biosynthesis in the spikes of djulis. The results of the combined multi-omics analysis showed that the metabolites associated with anthocyanin synthesis were mainly enriched in the flavonoid biosynthesis pathway (ko00941) and the anthocyanin biosynthesis pathway (ko00942). With the maturation of djulis spikes, a total of 28 differentially expressed genes and 17 differentially expressed metabolites were screened during the transition of spike color from green (G) to red (R) or orange (O). Twenty differentially expressed genes were selected for qRT-PCR validation, and the results are consistent with transcriptome sequencing. The upregulation of seven genes, including chalcone synthase (CfCHS3_1, CfCHS3_2, CfCHS3_3), flavanone 3-hydroxylase (CfF3H_3), flavonoid 3′5′-hydroxylase (CfCYP75A6_1), dihydroflavonol reductase (CfDFRA), and glucosyltransferase (Cf3GGT), promotes the formation and accumulation of delphinidin 3-sambubioside and peonidin 3-galactoside. The research results also showed that anthocyanins and betalains can coexist in the spike of djulis, and the reason for the change in spike color during development may be the result of the combined action of the two pigments. A possible regulatory pathway for anthocyanin biosynthesis during the spike maturation was constructed based on the analysis results. The results provide a reference and theoretical basis for further studying the molecular mechanism of anthocyanin regulation of color changes in Amaranthaceae plants. Full article

Jaboticaba is a typical tropical plant that blossoms and bears fruit on the tree trunks and branches. The fruits resemble grapes in appearance and texture and are also known as “treegrapes”. Currently, research on the genomics of jaboticaba is lacking. In this study, we constructed an integrated, telomere-to-telomere (T2T) gap-free reference genome and two nearly complete haploid genomes, thereby providing a high-quality genomic resource. Furthermore, we unveiled the evolutionary history of several species within the Myrtaceae family, highlighting significant expansions in metabolic pathways such as the citric acid cycle, glycolysis/gluconeogenesis, and phenylpropanoid biosynthesis throughout their evolutionary process. Transcriptome analysis of jaboticaba fruits of different colors revealed that the development of fruit skin color in jaboticaba is associated with the phenylpropanoid and flavonoid biosynthesis pathways, with the flavanone 3-hydroxylase (F3H) gene potentially regulating fruit skin color. Additionally, by constructing the regulatory pathway of the citric acid cycle, we found that low citric acid content is correlated with high expression levels of genes such as thiamin diphosphate (ThDP) and low expression of phosphoenolpyruvate carboxykinase (PEPCK), indicating that PEPCK positively regulates citric acid content. These T2T genomic resources will accelerate jaboticaba pepper genetic improvement and help to understand jaboticaba genome evolution. Full article

Waxy corn is a special type of maize primarily consumed as a fresh vegetable by humans. Nitrogen (N) plays an essential role in regulating the growth progression, maturation, yield, and quality of waxy maize. A reasonable N application rate is vital for boosting the accumulation of both N and carbon (C) in the grains, thereby synergistically enhancing the grain quality. However, the impact of varying N levels on the dynamic changes in N metabolism, carbohydrate formation, and anthocyanin synthesis in purple waxy corn kernels, as well as the regulatory relationships among these processes, remains unclear. To explore the effects of varying N application rates on the N metabolism, carbohydrate formation, and anthocyanin synthesis in kernels during grain filling, a two-year field experiment was carried out using the purple waxy maize variety Jinnuo20 (JN20). This study examined the different N levels, specifically 0 (N0), 120 (N1), 240 (N2), and 360 (N3) kg N ha⁻¹. The results of the analysis revealed that, for nearly all traits measured, the N application rate of N2 was the most suitable. Compared to the N0 treatment, the accumulation and content of anthocyanins, total nitrogen, soluble sugars, amylopectin, and C/N ratio in grains increased by an average of 35.62%, 11.49%, 12.84%, 23.74%, 13.00%, and 1.87% under N2 treatment over five filling stages within two years, respectively, while the harmful compound nitrite content only increased by an average of 30.2%. Correspondingly, the activities of related enzymes also significantly increased and were maintained under N2 treatment compared to N0 treatment. Regression and correlation analysis results revealed that the amount of anthocyanin accumulation was highly positively correlated with the activities of phenylalanine ammonia-lyase (PAL) and flavanone 3-hydroxylase (F3H), but negatively correlated with anthocyanidin synthase (ANS) and UDP-glycose: flavonoid-3-O-glycosyltransferase (UFGT) activity, nitrate reductase (NR), and glutamine synthetase (GS) showed significant positive correlations with the total nitrogen content and lysine content, and a significant negative correlation with nitrite, while soluble sugars were negatively with ADP-glucose pyrophosphorylase (AGPase) activity, and amylopectin content was positively correlated with the activities of soluble starch synthase (SSS), starch branching enzyme (SBE), and starch debranching enzyme (SDBE), respectively. Furthermore, there were positive or negative correlations among the detected traits. Hence, a reasonable N application rate improves purple waxy corn kernel nutritional quality by regulating N metabolism, as well as carbohydrate and anthocyanin biosynthesis. Full article

Camellia hainanica is one of the camellia plants distributed in tropical regions, and its regeneration system and genetic transformation are affected by callus browning. However, the underlying mechanism of Camellia hainanica callus browning formation remains largely unknown. To investigate the metabolic basis and molecular mechanism of the callus browning of Camellia hainanica, histological staining, high-throughput metabolomics, and transcriptomic assays were performed on calli with different browning degrees (T1, T2, and T3). The results of histological staining revealed that the brown callus cells had obvious lignification and accumulation of polyphenols. Widely targeted metabolomics revealed 1190 differentially accumulated metabolites (DAMs), with 53 DAMs annotated as phenylpropanoids and flavonoids. Comparative transcriptomics revealed differentially expressed genes (DEGs) of the T2 vs. T1 associated with the biosynthesis and regulation of flavonoids and transcription factors in Camellia hainanica. Among them, forty-four enzyme genes associated with flavonoid biosynthesis were identified, including phenylalaninase (PAL), 4-coumaroyl CoA ligase (4CL), naringenin via flavanone 3-hydroxylase (F3H), flavonol synthase (FLS), Chalcone synthase (CHS), Chalcone isomerase (CHI), hydroxycinnamoyl-CoA shikimate transferase (HCT), Dihydroflavonol reductase (DFR), anthocyanin reductase (LAR), anthocyanin synthetase (ANS), and anthocyanin reductase (ANR). Related transcription factors R2R3-MYB, basic helix-loop-helix (bHLH), and WRKY genes also presented different expression patterns in T2 vs. T1. These results indicate that the browning of calli in Camellia hainanica is regulated at both the transcriptional and metabolic levels. The oxidation of flavonoids and the regulation of related structural genes and transcription factors are crucial decisive factors. This study preliminarily revealed the molecular mechanism of the browning of the callus of Camellia hainanensis, and the results can provide a reference for the anti-browning culture of Camellia hainanica callus. Full article

To reveal the effect of sucrose concentration on the production of secondary metabolites, a metabolome and transcriptome joint analysis was carried out using callus induced from grape variety Mio Red cambial meristematic cells. We identified 559 metabolites—mainly flavonoids, phenolic acids, and stilbenoids—as differential content metabolites (fold change ≥2 or ≤0.5) in at least one pairwise comparison of treatments with 7.5, 15, or 30 g/L sucrose in the growing media for 15 or 30 days (d). Resveratrol, viniferin, and amurensin contents were highest at 15 d of subculture; piceid, ampelopsin, and pterostilbene had higher contents at 30 d. A transcriptome analysis identified 1310 and 498 (at 15 d) and 1696 and 2211 (at 30 d) differentially expressed genes (DEGs; log2(fold change) ≥ 1, p < 0.05) in 7.5 vs. 15 g/L and 15 vs. 30 g/L sucrose treatments, respectively. In phenylpropane and isoflavone pathways, DEGs encoding cinnamic acid 4-hydroxylase, chalcone synthase, chalcone isomerase, and flavanone 3-hydroxylase were more highly expressed at 15 d than at 30 d, while other DEGs showed different regulation patterns corresponding to sucrose concentrations and cultivation times. For all three sucrose concentrations, the stilbene synthase (STS) gene exhibited significantly higher expression at 15 vs. 30 d, while two resveratrol O-methyltransferase (ROMT) genes related to pterostilbene synthesis showed significantly higher expression at 30 vs. 15 d. In addition, a total of 481 DEGs were annotated as transcription factors in pairwise comparisons; an integrative analysis suggested MYB59, WRKY20, and MADS8 as potential regulators responding to sucrose levels in flavonoid and stilbene biosynthesis in grape callus. Our results provide valuable information for high-efficiency production of flavonoids and stilbenes using grape callus. Full article

Purple Pak-choi is rich in anthocyanins, which have both ornamental and edible health functions, and has been used more and more widely in facility cultivation. In order to further clarify the molecular mechanism of purple Pak-choi, two Pak-choi inbred lines (‘PQC’ and ‘HYYTC’) were selected for the determination of pigment content and transcriptome analysis, and the key genes controlling the formation of purple character in leaves of Pak-choi were discovered. The results of pigment determination showed that the anthocyanin content of ‘PQC’ was 0.29 mg/g, which was about 100 times than ‘HYYTC’; The chlorophyll content of ‘HYYTC’ was 2.25 mg/g, while ‘PQC’ only contained 1.05 mg/g. A total of 20 structural genes related to anthocyanin biosynthesis and 28 transcriptional regulatory genes were identified by transcriptome analysis. Weighted gene co-expression network analysis (WGCNA) was used to construct the weight network analysis map of 14 genes. The results showed that the cinnamate hydroxylase gene (BraA04002213, BrC4H3), flavanone-3- hydroxylase (BraA09004531, BrF3H1), and chalcone synthetase (BraA10002265, BrCHS1) were the core genes involved in the anthocyanin synthesis pathway of purple Pak-choi. The results identified the key genes controlling the formation of purple leaf traits, which laid a foundation for further analysis of the molecular mechanism of anthocyanin accumulation in purple Pak-choi and provided a theoretical basis for leaf color regulation. Full article

Sunburn stress is one of the main environmental stress factors that seriously affects the fruit development and quality of Chinese olive, a tropical and subtropical fruit in south China. Therefore, the understanding of the changes in physiological, biochemical, metabolic, and gene expression in response to sunburn stress is of great significance for the industry and breeding of Chinese olive. In this study, the different stress degrees of Chinese olive fruits, including serious sunburn injury (SSI), mild sunburn injury (MSI), and ordinary (control check, CK) samples, were used to identify the physiological and biochemical changes and explore the differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) by using transcriptomics and metabolomics. Compared with CK, the phenotypes, antioxidant capacity, and antioxidant-related enzyme activities of sunburn stress samples changed significantly. Based on DEG-based KEGG metabolic pathway analysis of transcriptomics, the polyphenol and flavonoid-related pathways, including phenylpropanoid biosynthesis, sesquiterpenoid, and triterpenoid biosynthesis, monoterpene biosynthesis, carotenoid biosynthesis, isoflavonoid biosynthesis, flavonoid biosynthesis, were enriched under sunburn stress of Chinese olive. Meanwhile, 33 differentially accumulated polyphenols and 99 differentially accumulated flavonoids were identified using metabolomics. According to the integration of transcriptome and metabolome, 15 and 8 DEGs were predicted to regulate polyphenol and flavonoid biosynthesis in Chinese olive, including 4-coumarate-CoA ligase (4CL), cinnamoyl-CoA reductase (CCR), cinnamoyl-alcohol dehydrogenase (CAD), chalcone synthase (CHS), flavanone-3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), and anthocyanidin synthase (ANS). Additionally, the content of total polyphenols and flavonoids was found to be significantly increased in MSI and SSI samples compared with CK. Our research suggested that the sunburn stress probably activates the transcription of the structural genes involved in polyphenol and flavonoid biosynthesis in Chinese olive fruits to affect the antioxidant capacity and increase the accumulation of polyphenols and flavonoids, thereby responding to this abiotic stress. Full article