Plant, Cell & Environment最新文献

Anthocyanins are protective pigments synthesised by plants to cope with several stressful situations. Anthocyanin synthesis is tightly controlled by multiple transcriptional mechanisms involving the action of activators and repressors. In this work, we report that the class I TCP transcription factor TCP15 and the Phytochrome interacting factor PIF4 negatively affect anthocyanin synthesis by directly inducing the expression of the gene encoding the sulfopeptide GOLVEN1/CLE-LIKE6 (GLV1/CLEL6), a recently identified repressor of anthocyanin synthesis in Arabidopsis thaliana. These transcription factors bind to a region of the GLV1/CLEL6 promoter containing nearby TCP-box and G-box motifs and are able to activate the expression of a reporter gene located under the control of the GLV1/CLEL6 promoter, supporting a direct regulation. Moreover, PIF4 binding to the GLV1/CLEL6 promoter is compromised in a double mutant of TCP15 and the related TCP gene TCP14, whereas TCP15 activation of the GLV1/CLEL6 promoter depends on PIF function, revealing a functional interdependence between these transcription factors. Furthermore, we found that TCP15 and PIF4 also participate in gibberellin-dependent repression of anthocyanin biosynthesis, acting at different levels but independently of GLV1/CLEL6. Altogether, our results add new information on the molecular mechanisms involved in the regulation of anthocyanin accumulation in plants.

Epigenetic modifications play pivotal roles in regulating plant adaptive responses to viral infection and various other stresses. However, how viral infection rewires and shapes chromatin-based epigenetic regulatory networks in crops with contrasting resistance remains unclear. To this end, we investigated the consequences of epigenetic variations in resistant and susceptible soybean cultivars following soybean mosaic virus (SMV) infection. SMV infection mediates the depletion of 24-nucleotide small interfering RNAs (24-nt siRNAs) in susceptible cultivars and induces the accumulation of 24-nt siRNAs in resistant cultivars. Twenty-four-nucleotide siRNA-dependent DNA methylation variable regions are preferentially enriched in euchromatic CHH contexts, and highly variable DNA methylation regions in heterochromatic long terminal repeat (LTR) retrotransposons are independent of 24-nt siRNAs. Moreover, SMV infection triggers extensive chromatin remodelling in susceptible cultivar, where the depletion of 24-nt siRNAs is related to reduced chromatin accessibility. Conversely, SMV infection mildly remodels chromatin accessibility at heterochromatic LTR retrotransposons in the resistant cultivar. Variations in 24-nt siRNA levels and DNA methylation in upstream regions of autophagy-related genes in susceptible cultivars may influence their expression. Our work provides insights into SMV-triggered divergent epigenetic regulatory networks in soybeans with contrasting resistance and provides a valuable foundation for investigating gene regulatory programmes based on epigenetic variations.

Fruit softening critically impacts postharvest quality and storage of peach (Prunus persica L.). To explore the molecular mechanism regulating postharvest peach softening and identify key genes for maintaining fruit quality, this study focused on investigating the function and regulatory network of S-adenosine-L-homocysteine hydrolase 1 (SAHH1). Postharvest peach fruits showed continuous firmness decline and significant anthocyanin accumulation after day 10, indicating a rapid softening initiation. qRT-PCR confirmed PpSAHH1 was strongly positively correlated with firmness (r = 0.648). PpSAHH1 overexpression in peach delayed senescence by maintaining firmness, retarding color change, and preserving cell membrane integrity, while heterologous expression in tomato regulated ripening. Bioinformatics revealed PpSAHH1 is a cytoplasmic acidic soluble protein with conserved structures, evolutionarily close to Prunus dulcis SAHH, and its promoter contains abscisic acid (ABA)-responsive elements. Stable overexpression in apple callus altered cell wall metabolism: reduced pectin and increased cellulose, hemicellulose, and lignin. Transcriptome analysis showed differentially expressed genes enriched in phenylpropanoid biosynthesis, calcium/auxin/ABA signaling, and plant-pathogen interaction. Yeast one-hybrid, dual-luciferase, and GUS assays verified myeloblastosis transcription factor 14 (PpMYB14) directly binds the PpSAHH1 promoter and activates its transcription. Silencing of MdMYB14 in apple significantly reduced the accumulation of total phenols and cell wall metabolic components, particularly lignin content. Collectively, the PpMYB14-SAHH1 module inhibits peach softening by coordinately regulating multiple signaling pathways and phenylpropanoid biosynthesis to promote lignin accumulation, offering new insights and potential targets for postharvest quality improvement.

Protein ubiquitination is a central regulatory mechanism governing plant growth, development and environmental adaptation. Ubiquitylomic studies have revealed that many enzymes in phenylpropanoid biosynthetic pathways are subject to ubiquitination. Increasing evidence indicates that specific F-box proteins target key enzymes in these pathways, including PAL, CCR, CAD, COMT and peroxidases in the lignin biosynthetic branch, and CHS in the flavonoid biosynthetic branch, thereby promoting their ubiquitination and selective degradation. These F-box proteins act in response to diverse developmental and environmental cues, including cellular carbon status, light quality and intensity, and biotic stresses (e.g., pathogen and insect attack). By regulating the stability and activity of both enzymes and regulatory proteins involved in phenylpropanoid biosynthesis, F-box proteins modulate the accumulation of simple phenolics and lignin polymers, ultimately contributing to plant resilience. This review summarizes recent advances in the characterization of F-box proteins involved in phenylpropanoid metabolism and their regulatory roles in response to biotic and abiotic stresses and identifies key knowledge gaps that limit mechanistic understanding of F-box protein-mediated proteolytic regulation of phenylpropanoid metabolism. Insights into ubiquitin-mediated proteolytic control of phenylpropanoid metabolism offer promising avenues for enhancing bioactive phenolic production, advancing biofuel feedstock engineering and improving crop stress tolerance.

Sustainable agriculture urgently requires innovative, pesticide-free strategies to mitigate herbivory and safeguard food security. Ultraviolet-B (UV-B) irradiation, with tunable intensity and cost-effectiveness, has emerged as a promising non-chemical method to enhance plant resistance, yet its underlying mechanisms remain elusive. Here, using tea plant (Camellia sinensis) and its major pest Ectropis obliqua as a model, we developed a multimodal framework that integrates AI-enhanced electronic nose technology for real-time volatile profiling with in situ hyperspectral stimulated Raman scattering (SRS) microscopy to characterize defense responses under precisely controlled UV-B treatments. This approach identified herbivore-induced volatiles-hexanal, (Z)-3-hexenol, octanal, and (Z)-3-hexenyl acetate-optimally induced at 1.2 kJ·m^-2 UV-B and linked to insect deterrence. SRS imaging further revealed elevated jasmonic acid derivatives and L-phenylalanine, coupled with reduced protein levels and altered stomatal dynamics, all correlating with enhanced resistance. Transcriptomic and molecular analyses confirmed transcriptional regulation of these pathways. By bridging volatile detection, metabolic imaging, and molecular validation, this study pioneers a multimodal strategy that provides mechanistic insights into UV-B-mediated plant defense and highlights the potential of multimodal methodologies as powerful tools for developing sustainable, pesticide-free pest management solutions in precision agriculture.

High nighttime temperatures (HNT) tend to diminish rice quality by disrupting assimilate translocation and grain filling process in rice (Oryza sativa L.). However, there is controversy remains regarding whether source or sink limitation are the primary driver under HNT during grain filling period. Additionally, the physiological mechanisms underlying the genotypic variation in the response of grain protein content to HNT and its effect on rice quality have been less explored. To address whether nitrogen remobilization from leaves to grains during grain filling determines genotypic differences in grain quality under high night temperature, two cultivars - HHZ (Huanghuazhan, an indica inbred line) and YY4949 (Yongyou4949, an indica-japonica hybrid) - were treated with 30/22°C (day/night, CK) and 30/27°C (HNT) over two consecutive years. Significant genotypic variation in the response of grain storage substances to HNT was observed between the two cultivars. Under HNT, YY4949 exhibited a significant increase in grain protein content and glutelin/prolamin ratio, and this shift negatively impacted rice eating and cooking quality. Notably, the protein/amylose ratio exhibited a stronger correlation with chalkiness degree and pasting characteristics of rice flour. Under HNT, accelerated nitrogen remobilization from leaves to grains in YY4949 - driven by enhanced chloroplast degradation and upregulated expression of nitrogen metabolism-related enzymes and transporters exacerbated source limitation to rice quality and disrupted the balance between starch and protein in grains. Collectively, these findings suggest that genetic modulation of nitrogen remobilization could facilitate the breeding of climate-resilient rice cultivars with superior grain quality.

In the North East Hill Region (NEHR) of India, acidic soils cause aluminum (Al³⁺) toxicity and phosphorus (Pi) deficiency, severely limiting crop productivity. Linseed offers potential for enhancing cropping intensity and diversification in this region. Contrasting oilseed-type linseed genotypes identified for yield traits under acidic soils were further validated for root and shoot traits through hydroponic screening. Using an orthology-based approach, eight gene families-MATE, ALMT1, MGT1, PT6, PAP15, WD40-38, SPL4, and ACA3-known to confer Al³⁺ toxicity and P deficiency tolerance in other plant species were targeted. Thirty-one genic regions were identified. In roots of four genotypes (Lus 37, Lus 237, Lus 4, and Lus 49) exposed to Al³⁺ toxicity, UGT74, MATE1365, MGT1272, and MGT1577 were upregulated in tolerant genotypes, indicating their probable roles in detoxification, transport, and ion homeostasis. Under low Pi conditions, eleven genes exhibited differential expression in shoots and roots of Lus 37, Lus 29, and Lus 4, with PT6826 and PT6635 upregulated in roots of tolerant Lus 37. Overall, LusMATE1365, LusUGT74, and LusPT6635 were identified as key candidate genes that could potentially confer tolerance to Al³⁺ toxicity and P deficiency. These insights will aid molecular breeding for linseed adaptation to acidic soils of NEHR.

Alnus glutinosa is one of only three lineages within the order Fagales capable of establishing root nodule symbiosis (RNS). Although a fragmented genome assembly of A. glutinosa was previously available, its limited quality, combined with the lack of comprehensive transcriptomic resources, has constrained in-depth comparative and functional genomic analyses. In this study, we present a 505 Mb chromosome-level genome assembly of A. glutinosa, anchored to 14 pseudochromosomes, representing the most complete and high-quality genomic resource for this species to date. Whole-genome alignment and synonymous substitution rate (Ks) analysis confirm Alnus and Betula as sister genera with shared genomic architectures and evolutionary histories. Functional enrichment analyses of nodule-enhanced genes reveal significant associations with photosynthesis and sugar metabolism, while expanded gene families are enriched in terpenoid biosynthesis and malate transport pathways, likely critical to RNS in A. glutinosa. Phylogenetic analysis indicated that Alnus has retained non-symbiotic class 1 haemoglobin (nsHB1), but lost nsHB2 haemoglobin, suggesting a lineage-specific adaptation in symbiotic oxygen regulation. Further comparative analysis of nsHB1 protein sequences across nodulating taxa highlights evolutionary patterns within the Alnus lineage. Through a targeted phylogenetic survey of known RNS-related genes, we identified PAV in RPG and copy number variation in AGO5, both of which may underlie Alnus-specific RNS adaptations. Weighted gene co-expression network analysis identified a nodule-specific module comprising 231 genes significantly enriched in sugar-related metabolic pathways. Notably, the bZIP ortholog shows conserved nodule-specific expression across species from Cucurbitales, Rosales and Fabales, suggesting deep evolutionary conservation within the nitrogen-fixing clade. Together, these findings provide a high-resolution view of Alnus-specific RNS adaptations and uncover conserved regulatory modules potentially critical for RNS. These works establish a foundational genomic framework for future efforts aimed at engineering RNS capacity into non-nodulating crops.