Search Results (196)

The FAR-RED IMPAIRED RESPONSE 1 (FAR1) and FAR-RED ELONGATED HYPOCOTYL 3 (FHY3) transcription factors, together with other members of the FAR1-RELATED SEQUENCE (FRS) and FRS-RELATED FACTOR (FRF) families, represent a striking example of transposable element domestication in plants. Derived from ancient Mutator-like element (MULE) transposases, these proteins have been repurposed as transcriptional regulators throughout the plant kingdom. FHY3 and FAR1 were first identified in Arabidopsis thaliana as positive regulators of phytochrome A (phyA) signaling. They participate in the coordination of light signaling with the circadian clock, chlorophyll biosynthesis, hormone pathways, stress responses, flowering time, shoot branching, leaf senescence, seed dormancy, and phosphate homeostasis. At the molecular level, FHY3 and FAR1 regulate gene expression mainly by binding to the conserved FHY3/FAR1-binding site, FBS, with the sequence CACGCGC, in the promoters of target genes. They also act through protein interactions with key signaling regulators, including HY5, PIFs, EIN3, TOC1, and SPL transcription factors. In this review, we summarize the molecular basis of FHY3/FAR1 gene family function, discuss the roles and mutant phenotypes of characterized family members, and highlight recent advances from other plant species beyond Arabidopsis. Collectively, this gene family illustrates how domesticated transposase-derived proteins have evolved into key regulators of plant development and environmental adaptation. Full article

Light intensity and spectral composition regulate plant physiological processes and productivity, particularly under low-light greenhouse conditions. This study was designed to address two main objectives in aeroponically grown potato (Solanum tuberosum L. cv. Agria). First, we evaluated the effects of supplemental light quality, focusing on different red (R), blue (B), and white (W) combinations at a constant intensity of 100 μmol m⁻² s⁻¹. Second, we assessed the specific effects of far-red (FR) light on plant performance and biomass allocation patterns. Potato plants were grown under greenhouse conditions in a completely randomized design consisting of eight supplemental LED spectral treatments and a natural-light control. Supplemental lighting increased net photosynthesis, stomatal conductance, chlorophyll content, and biomass compared to the control, demonstrating that moderate increases in light intensity improved plant performance under low-light conditions. Among the spectral treatments, W light and balanced R–B combinations increased net photosynthetic rate by 93.7–198.7% and total biomass by 23.8–132.1% relative to the control, suggesting improved coordination of stomatal activity, electron transport, and chlorophyll biosynthesis under the experimental light environment. In contrast, FR inclusion reduced the net photosynthetic rate and mini-tuber biomass by 15.0–38.6% relative to the corresponding FR-free treatments, particularly under treatments with lower red proportions, suggesting that FR effects are more likely associated with phytochrome-mediated regulation of photosynthetic efficiency and assimilate partitioning under modified red to far-red spectral balance rather than classical shade-avoidance responses. Mini-tuber yield was strongly affected by light treatments. White light and balanced R:B spectra produced the highest tuber number and biomass, increasing mini-tuber number and biomass by 26.6–62.5% and 15.4–87.7%, respectively, compared with the control, whereas FR reduced yield. Although FR appeared to increase the relative allocation of biomass to tubers, overall photosynthetic performance and biomass accumulation remained lower, resulting in lower productivity. Overall, mini-tuber production appeared to be associated with source–sink relationships, where light intensity enhanced photosynthetic performance and biomass production, light quality optimized photosynthetic performance, and FR light appeared to modify biomass allocation patterns. These findings highlight the importance of optimizing spectral composition and FR management in aeroponic seed potato production under low-light greenhouse conditions. Full article

Phytochrome-interacting factors (PIFs) were initially recognized as pivotal regulators of plant light signaling pathways. However, mounting evidence suggests that PIFs also exert significant influences on plant development and responses to stress. Here, we identified seven PIF genes in the potato genome and conducted comprehensive characterizations through phylogenetics, gene structure, conserved motif, synteny, chromosomal location analyses and cis-regulatory element. Transcriptome data and gene expression analysis showed that the StPIF4 gene was markedly induced by mannitol-induced water deficit. Additionally, the StPIF4 protein was primarily localized in the nucleus and plasma membrane. In order to explore the function of the StPIF4 gene under mannitol-induced water deficit, the StPIF4 gene was cloned, and several StPIF4 overexpression (OE) lines (OE-8, OE-10, and OE-11) and three RNA interference (RNAi) transgenic lines (RNAi-5, RNAi-9, and RNAi-11) were obtained. The OE lines displayed notable enhancements in various growth parameters such as plant height, leaf number, branch number, fresh weight, dry weight, total root length, root surface area, number of root forks, and number of root tips under mannitol-induced water deficit compared to the wild-type (WT) lines, whereas these parameters were significantly decreased in the RNAi lines. The activities of antioxidant enzymes (SOD, POD, CAT) and the accumulation of proline and soluble sugars were also significantly increased under mannitol-induced water deficit, whereas the levels of thiobarbituric acid reactive substances (TBARSs) and reactive oxygen species (ROS), including hydrogen peroxide (H₂O₂) and O₂⁻, were significantly reduced in the OE lines compared to WT plants under mannitol-induced water deficit. Moreover, the stomatal aperture of the leaves and the water loss rate in the leaves of the OE lines were significantly reduced under mannitol-induced water deficit compared to the WT plants, whereas for the RNAi lines they were significantly increased. In addition, the overexpression of StPIF4 also upregulated expression of drought-responsive genes and ABA content under mannitol-induced water deficit. Collectively, these results highlight the positive role of the StPIF4 gene in enhancing potato tolerance to mannitol-induced water deficit by decreasing stomatal aperture, enhancing ROS scavenging and mitigating oxidative damage. Full article

Medicinal plants grown outside their native forest habitat may produce phytochemical profiles that differ from wild-harvested material, yet the ecological mechanisms underlying these differences remain poorly synthesized across disciplines. This review proposes that the forest understory functions as a multi-signal elicitation system in which canopy light filtering, arbuscular mycorrhizal fungi (AMF), and above-ground biotic interactions collectively shape secondary metabolite profiles. AMF-mediated induced systemic resistance and above-ground biotic interactions operate through confirmed jasmonate-mediated pathways. Sunfleck-driven reactive oxygen species signaling is hypothesized but untested, and the red-to-far-red ratio modulated phytochrome B pathway characterized in Arabidopsis remains unconfirmed in shade-tolerant species. Using three saponin-rich medicinal plants (Panax vietnamensis, Panex quinquefolius, and Paris polyphylla) as case studies, we formalize this as a testable chemical terroir hypothesis with three falsifiable predictions. We also translate it into an ecological co-cultivation design principle with three production levels and a two-step operational framework, and identify priority experiments, analytical methods, and implementation challenges needed for validation. These contributions bridge forest ecology and medicinal plant science while identifying critical evidence gaps requiring resolution before field implementation. Full article

The expression of two genes, Fum1 and Fum2, encoding the mitochondrial and cytosolic forms of fumarase (EC 4.2.1.2); the methylation of individual CpGs of their promoters; and fumarase activity were studied in sunflower (Helianthus annuus L.) leaves depending on irradiation and salinity. Fumarase activity was twice as high in darkness compared to irradiation by white light and red light, while far-red light applied after darkness or after red light reverted the activity to the values in darkness, which indicates the involvement of phytochrome. Using qRT-PCR, it was demonstrated that this corresponded to the pattern of expression of the Fum1 gene, while the expression of the Fum2 gene was higher upon irradiation by white and red light, and lower in darkness and under far-red light. Under the application of 150 mM NaCl for 1, 3, 6, 12, and 24 h, fumarase activity increased fivefold from the start of incubation to 6 h, and then decreased after 12 h. These changes were associated with the transcriptional regulation of the Fum1 and Fum2 genes. Changes in the methylation status of the analyzed CpGs in their gene promoters, detected via semi-quantitative methylation-specific PCR, were associated with differences in their expression. The higher methylation levels of the analyzed CpGs in the Fum1 gene promoter under different light conditions and in the Fum2 gene promoter under salinity corresponded to low levels of their transcripts in sunflower leaves. It is suggested that the mitochondrial and cytosolic forms of fumarase are regulated by light and salinity at the gene expression level, presumably through changes in the methylation status of individual CpGs in their promoters. Full article

Perennial groundcover (PGC) systems integrate perennial grasses with annual crops such as corn (Zea mays L.) to provide continuous soil cover and enhance soil health. However, the proximity to groundcover vegetation can alter light quality perceived by developing seedlings, inducing shade avoidance response (SAR), a phytochrome-mediated developmental response that modifies plant architecture and may compromise yield. Identifying the distance at which SAR is initiated and the extent to which management practices modulate this response is critical for optimizing PGC systems. This growth chamber study aimed to (1) identify the distance at which SAR occurs in corn seedlings, (2) determine whether the thiamethoxam seed treatment mitigates SAR expression, and (3) compare hybrid physiological responses to PGC-induced SAR. The experiment was arranged in a randomized complete block design with four replications across three periods and included two corn hybrids (P1185, P1197), two seed treatments (untreated and thiamethoxam at 0.25 mg seed⁻¹), and four perennial ryegrass (Lolium perenne L.) distances [0, 6, 25 cm, and a control (no-grass)]. Reduced red to far-red light ratios associated with closer proximity to ryegrass induced SAR responses. Corn plants at 6 cm from PGC exhibited significant stem and height elongation beginning at 8 days after planting (DAP), followed by reduced growth by 14 DAP, confirming an early SAR response. Plants grown at 0 cm exhibited reduced height and growth compared to other distances at all growth stages. Hybrid responses differed, and Hybrid P1197 showed enhanced stem elongation, a characteristic SAR response. The thiamethoxam seed treatment did not mitigate SAR. These results indicate that SAR causes stem elongation without altering root or shoot biomass. Full article

Far-red phosphors featuring high quantum efficiency and emission bands that strongly overlap with the absorption spectra of plant pigments are crucial for advancing plant cultivation lighting technology. Restricted by the large Stokes shift, far-red phosphors typically exhibit low energy efficiency. Moreover, many far-red phosphors suffer from low quantum efficiency, which has emerged as a critical issue in the research of these materials. To address the issue, conventional strategies—including crystal field engineering, defect engineering, and sensitizer doping—have been widely adopted to enhance their emission intensity. In this work, we propose a novel and effective strategy to improve the emission performance of far-red phosphors: low-melting-point magnesium chloride has been introduced as a flux to regulate the reaction pathway of the composite oxide phosphor Ca₁₄Mg_5.94Li_0.03In_0.03Ga_9.95O₃₅:0.05Mn⁴⁺ (CMLIGO:0.05Mn⁴⁺). The cubic intermediate product with a structure analogous to the target product has been designed to form a compact lattice structure and reduce crystal defects, thereby enhancing the luminescence intensity and quantum efficiency of the phosphor. The Ca₁₄Mg_5.94Li_0.03In_0.03Ga_9.95O₃₅:0.05Mn⁴⁺@3 wt% MgCl₂ (CMLIGO:0.05Mn⁴⁺@3 wt% MgCl₂) shows a broad excitation band (250–600 nm) and far-red emission centered at 720 nm (650–800 nm). Under 365 nm excitation, the CMLIGO:0.05Mn⁴⁺@3 wt% MgCl₂ exhibits an internal quantum efficiency of 91.4%. Benefiting from its high internal quantum efficiency and the emission band that matches well with the absorption spectrum of phytochrome in the far-red absorbing form (phytochrome P_fr), CMLIGO:0.05Mn⁴⁺@3 wt% MgCl₂ demonstrates promising potential for applications in plant cultivation lighting. This work offers a new direction for synthesizing and modification of composite oxide phosphors. Full article

Early and recent studies have demonstrated that exposure to moonlight influences the entire life cycle of plants from seed germination to vegetative growth and reproduction. Exposure to moonlight was found to induce genome reorganization in plants and significant changes in gene expression, protein, and metabolite profiles. However, the specific factors that facilitate moonlight perception are unknown. To uncover the photoreceptors responsible for moonlight perception, we analyzed Arabidopsis phototropin mutants (phot1, phot2, and phot1phot2) as well as the phytochrome mutants phyA and phyB for their response to full moonlight (FML). De-etiolation assays revealed that plants do perceive and respond to FML within 5 h of exposure. Thus, among the photoreceptor mutants analyzed, only phot1 and phot1phot2 were impaired in apical hook opening and cotyledon unfolding under FML. Interestingly, under high light intensity, all examined mutants underwent proper de-etiolation. Further analysis showed that phot1 as well as phyB mutants were impaired in response to moonlight, displaying no changes in nuclear size and in protein profiles following exposure to FML and were comparable to plants exposed to dark. The FML (5 h exposure) did not induce the formation of fewer, large nuclear photobodies, as occurred following 5 h exposure to growth-room light. Our findings highlighted phot1 and phyB as photoreceptors necessary for plants to perceive and respond to FML. It is proposed that the initial perception of moonlight is facilitated by the blue-light receptor phot1 and is subsequently interpreted into a functional state by the R/FR receptor phyB. Full article

Fructokinase (FRK) initiates fructose phosphorylation, channeling carbon into central metabolic pathways, yet its functional diversity and regulatory networks in C₄ cereals remain poorly understood. Here, we performed a comprehensive pan-genome analysis of the FRK gene family in foxtail millet (Setaria italica), identifying 697 SiFRKs across 110 accessions and revealing extensive presence–absence variation shaped by evolution and domestication. Among nine characterized members in the reference genome, SiFRK4 exhibited broad and high expression, a diurnal rhythm, and substantial natural variation. Biochemical assays confirmed its fructokinase activity in vitro. We discovered a novel physical interaction between SiFRK4 and the key photoreceptor Phytochrome C (SiPhyC), which co-localized in the cytoplasm. Functional analysis of SiPhyC mutants demonstrated that loss of SiPhyC disrupted carbohydrate homeostasis, elevating fructose while depleting sucrose and starch. Our findings reveal a physical and genetic link between the light-signaling component SiPhyC and the metabolic enzyme SiFRK4, suggesting their interaction influences carbon partitioning. This study provides foundational insights into the sugar metabolism network of a resilient C₄ model crop and identifies potential targets for metabolic engineering and breeding. Full article

Aspergillus flavus (A. flavus) is a common contaminant of food and feed due to the production of aflatoxin B₁, which is susceptible to environmental signals. Nevertheless, how red light plays a role in A. flavus remains unclear. Here, we identified the uncharacterized hypothetical protein G4B84_010091 as a red-light sensor, defined as fungal phytochrome A (FphA), in A. flavus. The fphA knockout strain (ΔfphA) and complementary strain (fphA-com) were successfully constructed to characterize the function of FphA. Our results indicated that aflatoxin B₁ biosynthesis was promoted, while the development of conidia and sclerotia as well as the infection of peanuts were impaired in ΔfphA when compared with WT or fphA-com. The FphA^ΔRR domain deletion mutant exhibited all the phenotypes observed in the ΔfphA strain, indicating that the RR domain is indispensable for the function of FphA. In summary, FphA is involved not only in the formation of spores and sclerotia, but also in aflatoxin B₁ biosynthesis and the pathogenicity of A. flavus, which offers a potential target for novel approaches to controlling the dispersal and toxin production of this fungus. Full article

Light-emitting diode (LED) technology allows for precise spectral tailoring in controlled-environment agriculture, with red light (R; 600–700 nm) acting as a central regulator of plant photophysiology through phytochrome (PHY)-mediated control of photosynthesis, morphology, and metabolic adjustment. This review synthesizes the current knowledge of the benefits and limitations of monochromatic and multichromatic R-containing LED systems under both optimal and saline conditions. Monochromatic R light enhances chlorophyll biosynthesis, carbon assimilation, and biomass accumulation; however, its exclusive application can restrict stomatal regulation, photoprotection, and secondary metabolism due to the absence of blue (B)- and green (G)-light-dependent signaling pathways. In contrast, multichromatic spectra incorporating R—particularly R-B, R-far-red (R-FR), and R-centered multi-spectral combinations with white (W) or G wavelengths—provide broader physiological advantages. These include improved photosystem II efficiency, pigment stability, ion homeostasis, antioxidant defense, and metabolic quality, while also optimizing canopy light distribution and energy use efficiency. Under salinity stress, R-containing spectral combinations consistently outperform monochromatic R by enhancing osmotic adjustment, reducing oxidative damage, and maintaining photosynthetic integrity. Nevertheless, species-specific sensitivity, ratio-dependent responses, and potential risks such as excessive elongation under FR enrichment highlight the need for careful spectral optimization. Despite substantial progress, the mechanisms underlying the integration of PHY signaling with salinity-responsive networks remain insufficiently resolved. Advances in multi-omics approaches and dynamic spectral management will be critical for the development of R-based LED strategies that sustainably enhance crop performance and stress resilience in controlled environments. Full article

Stem mustard (Brassica juncea var. tumida Tsen et Lee) is an important economic vegetable in China. Premature bolting induced by temperature fluctuations has become a major cultivation constraint. Photoreceptors (PHRs) serve as critical photosensor proteins that interpret light signals and regulate physiological responses in plants. In this study, five core PHR families, namely F-box-containing flavin binding proteins (ZTL/FKF1/LKP2), phytochrome (PHY), cryptochrome (CRY), phototropin (PHOT) and UV RESISTANCE LOCUS 8 (UVR8) were identified in Brassica species. RNA-seq analysis revealed their expression patterns during organogenesis in B. juncea. Seven candidate PHRs were validated by qRT-PCR in B. juncea early-bolting (‘YA-1’) and late-bolting (‘ZT-1’) cultivars. Agrobacterium-mediated BjuFKF1_1 overexpression (OE) lines resulted in significantly earlier flowering under field conditions. Histochemical GUS staining indicated that BjuFKF1_1 was expressed in seedlings, leaves, flower buds and siliques. Transcript analysis revealed that the expression level of BjuFKF1_1 was up-regulated in all tissues at both the vegetative and reproductive stages, whereas the expression of BjuFKF1_1 interacting protein-encoding genes were down-regulated in flowers. Under blue light, genes encoding interacting proteins (BjuCOL5, BjuSKP1, BjuCOL3, BjuAP2, BjuAP2-1 and BjuLKP2) were up-regulated in flower buds, whereas BjuCOL and BjuPP2C52 were down-regulated in flowers. Developmental stage analysis revealed the up-regulation of five (BjuAP2, BjuCOL3, BjuCOL5, BjuAP2-1 and BjuLKP2) and four (BjuCOL, BjuCOL5, BjuAP2 and BjuLKP2) interaction protein-encoding genes during the reproductive stage under white and blue light, respectively. These findings elucidate the role of BjuFKF1_1 in flowering regulation and provide molecular targets for B. juncea bolting-resistant variety breeding. Full article

Phytochrome-interacting factors (PIFs) are key transcriptional regulators of phytochrome signalling that coordinate photomorphogenesis and photosynthesis under different environmental conditions. PIFs play an important role in this regulation and act mainly as negative regulators of photomorphogenesis, but under high-intensity light (HIL), their functions can also include adaptive roles. We investigated the contribution of individual PIFs to the adaptation of the photosynthetic apparatus in wild-type A. thaliana and pif4, pif5, pif4pif5, and pif1pif3pif4pif5 mutants exposed to HIL for 0, 16, 32, or 48 h. Chlorophyll fluorescence parameters (Y(II), F_v/F_m, NPQ), net photosynthesis (Pn), transpiration rates, stomatal conductance (g_S), pigment contents and the expression of key genes were evaluated. The response of plants to HIL varied depending on the duration of exposure. After 16 h of irradiation, the greatest reductions in Pn and g_S were observed in the pif4pif5 and pif1pif3pif4pif5 mutants, whereas after 48 h, the decreases were most pronounced in the pif4, pif5, and pif4pif5 mutants. After 16 h of HIL exposure, the absence of pif4 and pif5 did not substantially alter the chlorophyll fluorescence parameters. However, after 48 h, both Y(II) and Fv/Fm were lower in these mutants than in the wild type, indicating changes in PSII functional status rather than direct reductions in photochemical quantum efficiency. At 16 h, chlorophyll levels were the highest in pif5 and WT, whereas anthocyanin and UV-absorbing pigment (UAP) levels were the highest in pif4, pif5 and WT. After 48 h, the highest levels of any pigments were detected in the WT and the pif1pif3pif4pif5 mutant. These results suggest that the accumulation of anthocyanins and UAPs under HIL is likely associated with the regulation of transcription factors, such as PIFs, de-etiolated 1 (DET1), constitutive photomorphogenic 1 (COP1), and elongated hypocotyl 5 (HY5). During prolonged HIL exposure, the absence of PIF4 and PIF5 has a critical impact on photosynthesis and the accumulation of photosynthetic pigments, whereas the simultaneous loss of PIF1, PIF3, PIF4, and PIF5 is less detrimental. This finding likely indicates opposite roles of PIF1 and PIF3 in the above-described processes, on the one hand, and PIF4 and PIF5, on the other hand, under HIL conditions. Full article

The coordinated development of stems and branches, together with optimal strip spacing, is crucial for improving soybean yield in the soybean–maize relay strip intercropping system. Shading during the seedling stage often causes excessive stem elongation and reduced branching; however, the physiological mechanisms underlying stem–branch responses to changing light environments remain unclear. This study aimed to clarify how early-stage shading and subsequent light recovery regulate stem and branch development through changes in canopy light environment, phytohormones, and the expression of related genes. Shade-tolerant Nandou12 and shade-sensitive Nannong99-6 were used as experimental soybean cultivars. Six treatments were implemented: a non-shaded control with uniform strip spacing (T0: 40 cm); seedling shading (40% PAR-transmission nets for 35 days after emergence) combined with variable strip spacing (T1: 40 cm; T2: 70 cm; T3: 100 cm; T4: 130 cm; T5: 160 cm). Canopy light environment, main stem and branch traits, photosynthetic characteristics, phytohormones, related gene expression, and yield components were measured. The results indicated that shade at the seedling stage significantly upregulated auxin (IAA) biosynthesis gene GmYUCC and downregulated phytochrome gene GmPhyB in the main stem tips, corresponding to increased IAA and cytokinins (CKs). In branch tips, shading significantly downregulated GmYUCC and GmPhyB while upregulated GmMAX3B, which is consistent with reduced levels of IAA, CKs, and brassinosteroid (BR), and increased strigolactones (SLs). After light recovery, GmPhyB and GmYUCC were upregulated whereas GmMAX3B was downregulated, accompanied by higher IAA, GA, CKs, and BRs, lower SLs, and improved chlorophyll content, Rubisco content, photosynthesis, and the accumulation of soluble sugar and starch in branches. Nandou12 achieved up to 10% higher yield under shading, and a 100 cm strip spacing maintained 74–111% yield of the non-shaded soybean. These findings demonstrate that cultivars with strong shade tolerance and high branching potential, combined with a 100-cm strip spacing, effectively sustain yield in relay-intercropped soybean by enabling favorable physiological responses to early shading and subsequent light recovery. Full article

Confronted with increasing global food demands, diminishing arable land, and climate volatility, controlled-environment agriculture with advanced red and far-red LED lighting can enhance photosynthesis and optimize plant growth. This investigation reports the generation of a Mn⁴⁺/Nd³⁺ co-doped Y₂SiO₅ phosphor with a Nd³⁺ concentration ranging from 0.1 to 2.5 mol% via a solid-state synthesis method, aiming to enhance red and far-red emission for plant cultivation LEDs. For the Y₂SiO₅:Mn⁴⁺ (1 mol%), Nd³⁺ (2 mol%) phosphor, the phase integrity, nanostructured morphology, elemental mapping, and vibrational characteristics were examined using XRD, Rietveld analysis, FTIR, SEM, and EDX. Nd³⁺ ions act as near-infrared excitation mediators, ensuring efficient Nd³⁺ → Mn⁴⁺ energy transfer upon 808 nm excitation, and this leads to pronounced red photoluminescence from Mn⁴⁺ ions that covers the range of 640–710 nm, exhibiting strong emission peaks centered at 650nm, 663nm, and 685nm, coinciding with the absorption band of phytochromes and chlorophyll. The optimal emission intensity was accomplished for a Nd³⁺ doping concentration of 2 mol%, beyond which concentration quenching occurred. The material produced a strong, concentrated deep red emission with CIE coordinates near (0.73, 0.27) and a high color purity of 98.96%, making it well-suited for photosynthetic activation. A phosphor-integrated red pc-LED was fabricated, and Tulsi plants were grown under this LED during the winter in Meghalaya, a period critical for plant growth due to the low ambient light. Over a 30-day period, the plants exhibited enhanced height and leaf development, demonstrating the practical potential of Mn⁴⁺/Nd³⁺ co-doped Y₂SiO₅ for energy-efficient, wavelength-optimized horticultural lighting. Full article