Physiologia plantarum最新文献

Polyploid plants often present a variety of agriculturally advantageous traits, such as larger organs. Plant cell expansion is ultimately constrained by the cell wall, yet the impact of polyploidization on the cell wall architecture of orchids remains unexplored. Here, we employed Dendrobium catenatum (syn. D. officinale) as a model to dissect the impacts of polyploidization on phenotypic traits, cell size and cell wall composition. Compared with diploids, tetraploids of D. catenatum have larger organs underpinned by larger cells. The analysis of gene expression revealed that the differentially expressed genes (DEGs) were significantly enriched in the cell wall metabolism and DNA packaging pathways. The cell wall component lignin- and xylan-related transcripts were upregulated, whereas histone-variant genes were repressed. Compositional assays revealed that the contents of many cell wall components, such as lignin, are increased in tetraploids. Despite cell wall reinforcement, tetraploids remained colonized by the symbiotic fungus Serendipita indica, although fungal biomass was moderately reduced. Thus, polyploidization enlarges D. catenatum by reprogramming cell wall construction, while preserving the plant's ability to maintain fungal symbiosis.

Receptor-like kinases (RLKs) detect external and internal signals, triggering responses essential for growth and adaptation. Among internal cues, cell wall integrity (CWI) sensing plays a key role, as changes in cell wall structure activate responses critical for development and defense. While RLKs are well-studied in vascular plants, their diversity and function remain largely unknown in green algae belonging to the Chlorophyta phylum, a group that is relevant for global oxygen production and carbon cycling. Due to their varied cell wall structures, Chlorophyta offer a useful system to study the origins of CWI sensing. In this study, we used advanced bioinformatics and AI-based tools to analyze RLKs in 34 Chlorophyta species, mapping their distribution, structural features, and similarity to plant RLKs. We identified 736 putative RLKs, expanding the known repertoire in green algae. Structural analyses showed a wide range of extracellular domains, including motifs related to plant CWI sensors: domains mediating protein interactions (e.g., Leucine Rich Repeats-LRR, Plasminogen Apple Nematod e-PAN, Armadillo repeat-ARM), cell wall remodeling (e.g., glycosyl hydrolases, lyases), and mechanosensing (e.g., Leucine-Proline-X-Threonine-Glycine motifs-LPXTG, Fibronectin). This diversity suggests that mechanisms for extracellular sensing and CWI monitoring emerged early in evolution. The results provide a basis for future studies on the function of RLKs in algae and their evolutionary links to vascular plant signaling.

Fruit quality in wampee is strongly influenced by the accumulation of key metabolites, including anthocyanins, sugars, and organic acids, yet their metabolic dynamics during fruit development remain poorly understood. In this study, we analyzed metabolite profiles and the expression of metabolism-related genes in the pulps of two wampee cultivars, "Jixin" (JX) and "Zirou" (ZR), across multiple fruit developmental stages. Two anthocyanins, 17 sugars, and 32 organic acids were identified. Total phenolics, flavonoids, starch, and soluble sugars accumulated mainly during early fruit development. "JX" wampee exhibited higher ascorbic acid levels than "ZR" wampee. Sucrose and citric acid were the predominant sugars and organic acids in both cultivars. Transcriptomic analysis revealed 37 anthocyanin-related, 29 sugar-related, and 18 organic acid-related genes. Strong correlations between candidate gene expression and metabolite levels suggest that these genes play key roles in regulating the biosynthesis and accumulation of anthocyanins, sugars, and organic acids in wampee.

Rose represents the most traded cut flowers worldwide with enormous diversity in floral organs, especially petal number, a target trait during modern rose breeding. With a detailed phenome analysis, we here report the high variation pattern in floral organ number among 132 rose lines, including wild species, traditional Chinese varieties, and modern lines. Seven wild species are single- or five-petaled flowers. Intriguingly, compared to traditional Chinese roses, modern lines feature more floral organs in the inner three whorls simultaneously (about 36% more total floral organs), a pattern that has not been identified previously. More floral organs correlate with the increase of flower meristem size, a pattern tightly controlled by the CLAVATA3 (CLV3) and its related molecular module in known model species. Within the vicinity of a known petal number QTL, in which polymorphism in APETALA2 (AP2) has been hypothesized to regulate the rose double flower trait, we identified the presence of CLV3, whose expression domain conversely correlates with total floral organ numbers in roses. Genetic alteration of CLV3 expression in both rose and Arabidopsis significantly altered the meristem size and the floral organ development and number. Exogenous application of rose CLV3-encoded CLAVATA3/EMBRYO SURROUNDING REGION-related (CLE) peptide led to reduced meristem size, accompanied by reduced root length in both rose and Arabidopsis plants. Collectively, our data suggest that, either alone or working potentially together with the AP2 variation, expression diversity in CLV3 may serve as an important factor regulating floral organ number diversity in roses. These findings thus provide fresh insights into the molecular mechanisms underlying the floral organ number trait in both roses and other ornamental plants.

Blockage of xylem vessels can compromise water flow in trees, eventually leading to reduced gas exchange and productivity. The extent of these impairments also depends on how effectively blocked vessels can be bypassed through lateral pathways. We hypothesize that the ability to bypass can vary crucially between different species of the same clade, leading to differences in the hydraulic limitations after a defined loss of conducting vessels. Here, we test this hypothesis on 1-year-old seedlings of two Mediterranean angiosperm tree species, carob (Ceratonia siliqua) and oak (Quercus calliprinos). We consecutively notched stems to artificially block water flow through vessels in one half of the cross-section. We measured the effect of notching on leaf gas exchange and visualized altered water flow pathways using microscopy and μCT imaging. In carobs, stomatal conductance (g_s) of leaves on the notched side decreased by more than 90%. Water transport in the notched side of the stem had ceased. In oaks, leaves on the notched side maintained more than 50% of their g_s with no signs of dehydration. Microscopy and μCT imaging revealed that water supply to these leaves occurred through lateral pathways outside vessels. This can be explained by the presence of tangentially oriented arrays of tracheids with bordered pits, which we found in oaks but not carobs. Our study emphasizes the importance of non-vessel water flow in angiosperm trees when the xylem becomes partially blocked.

The carob tree (Ceratonia siliqua L.), an evergreen legume native to West Asia and long cultivated throughout the Mediterranean basin, is valued for its drought tolerance, nutritious pods, and ecological value. Despite its economic and environmental importance, genomic resources for this species have been limited. Here, we present a high-quality, chromosome-scale genome assembly of C. siliqua, generated using PacBio HiFi long-read and Hi-C sequencing technologies. The final assembly spans 501.39 Mb, organized into 12 pseudomolecules, with a scaffold N50 of 39.58 Mb. Genome annotation identified 30,295 protein-coding gene models, with 99.5% completeness according to conserved single-copy orthologs. Repetitive elements account for 52.2% of the genome, primarily long terminal repeat (LTR) retrotransposons of the Gypsy and Copia families. Comparative orthology analysis with 24 other plant genomes revealed conserved gene content and a substantial number of species-specific genes in C. siliqua. Demographic inference using the PSMC model indicated historical population size fluctuations, with convergence in effective population size between Cretan and Moroccan populations approximately 50,000 years ago. Notably, we investigated the potential for symbiotic nitrogen fixation, a trait ancestral to legumes. Genomic evidence suggests pseudogenization of key nodulation genes (NIN and RPG), consistent with ecological observations of the absence of root nodules. These results support the hypothesis of a secondary loss of nodulation in C. siliqua. This genome provides a valuable resource for evolutionary, ecological, and agricultural studies, particularly for understanding legume adaptation to Mediterranean climates and the molecular basis of symbiotic regression.

Verticillium wilt (VW) is a soil-borne fungal plant disease. Gossypium hirsutum varieties with the widest planting area are highly susceptible to VW pathogens, because their narrow genetic background of germplasm resources causes difficulties in cultivating VW-resistant varieties through intraspecific breeding. Therefore, G. barbadense cultivars, harboring a natural VW resistance, become ideal donor materials to cultivate high-yield and multi-resistance chromosome segment substitution lines (CSSLs) through hybridization and backcrossing with G. hirsutum receptor and recurrent parent. In order to investigate the molecular mechanism of cotton response to VW infection, a BC₅F_3:5 CSSL MBI9626 and its parents, CCRI36 (G. hirsutum) and Hai1 (G. barbadense), were chosen to perform transcriptome and metabolome sequencing on their root samples at 0, 7, and 15 days after inoculation (DAI) of V. dahliae V991. In total, 36,564 differentially expressed genes (DEGs) and 102 differentially accumulated metabolites (DAMs) were separately identified from 12 pairwise comparison groups among the 27 samples. Of those, 125 common DEGs were found to participate in the biological processes of oxylipin metabolism, jasmonic acid (JA) biosynthesis/metabolism, and response to wounding in Gene Ontology (GO) enrichment analyses, while most of the DAMs were significantly enriched in tyrosine, purine, and phenylalanine metabolism pathways in enrichment analyses of Kyoto Encyclopedia of Genes and Genomes (KEGG). Having performed a conjoint KEGG analysis of all the DEGs and DAMs, we found two commonly enriched pathways, namely plant hormone signal transduction and flavonoid biosynthesis, which were consistent with the enrichment annotations of the significant model in weighted gene co-expression network analysis on the 2091 DEGs identified by an intersection of the genes in 40 previous QTLs and the total DEGs of this RNA-seq data. Among the ABA signaling pathway, the gene GH_D12G0236 (GHABF3) was selected to be used to perform virus-induced gene silencing (VIGS) verification in CCRI36 and MBI9626, and GHABF3-silenced plants showed a more serious wilting phenotype, an increased disease index (DI), and higher accumulation of fungal biomass compared to their empty-vector plants. These results provide a high-efficiency strategy for screening vital genes affecting cotton VW resistance, and lay a solid foundation for further cotton molecular breeding.

Mulberry bacterial wilt disease is devastating to the sericulture industry, and understanding its causal agent and pathogenic mechanisms is essential for effective mulberry disease control. In this study, the strain MSG-1, which was isolated from mulberry branches with typical bacterial wilt symptoms, was identified and designated as Ralstonia pseudosolanacearum MSG-1 according to the pathogenic, morphological, physiological, biochemical, and molecular features. Furthermore, R. pseudosolanacearum MSG-1 was classified as race 5, biovar I, phylotype I, and sequevar 12, and was capable of infecting mulberry but infected ginger, banana, and other Solanaceae weakly or not at all. The complete R. pseudosolanacearum MSG-1 genome is 5.8 Mbp (66.85% GC), and a total of 1991 genes of R. pseudosolanacearum MSG-1 were found to be significantly differentially expressed during the infection of mulberry seedlings, with 1324 genes significantly up-regulated and 667 genes significantly down-regulated. Seven pathogenicity-associated candidate genes were identified, and R. pseudosolanacearum MSG-1 pathogenicity on mulberry was significantly reduced after knocking out six of these genes. This study integrates genomic insights with the pathogenicity mechanisms of R. pseudosolanacearum MSG-1, shedding light on the breeding of resistant mulberry varieties and precision-based wilt control in sericulture.

Leaf margin morphology, encompassing entire, serrated, and lobed forms, is a key feature of leaf architecture with profound developmental, ecological, and evolutionary significance. This review synthesizes recent advances in understanding the regulation of leaf margin development, highlighting the integration of genetic, hormonal, and environmental cues. Central gene families such as cup-shaped cotyledon (CUC), Knotted1-like homeobox (KNOX), TCP, WOX, and LMI1/RCO are discussed in the context of their roles in promoting or restricting marginal growth. Hormonal regulators, particularly auxin, cytokinin, and gibberellin, interact through complex spatial feedback loops to fine-tune margin patterning, often mediated by key transporters, transcription factors, and miRNA modules. Age-dependent transitions, primarily regulated by the miR156-SPL pathway, modulate leaf margin complexity in both herbaceous and woody species. In addition to intrinsic genetic programs, extrinsic factors such as light intensity, temperature, nutrient availability, herbivory, and pathogen attack significantly influence margin development, demonstrating the plasticity of leaf morphology in response to environmental conditions. The integration of environmental signals into hormonal and gene regulatory networks enables plants to optimize leaf structure for photosynthesis, thermoregulation, and defense. This review also identifies emerging tools, such as spatial transcriptomics and genome editing, that promise to unravel the dynamic regulation of margin morphogenesis. By unifying developmental and environmental perspectives, we provide a conceptual framework for future studies on leaf form diversification and offer insights for potential applications in plant adaptation and crop improvement.

Kale (Brassica oleracea var. acephala) is a natural product rich in bioactive substances and a good source of functional compounds. This study evaluated the individual and combined effects of exogenous brassinolide (BR, 0.1 mg L^-1) and sucrose (Suc, 34.2 mg L^-1) on photosynthesis, sugar metabolism, the AsA-GSH cycle, nitrite accumulation, phytochemical composition, and nutritional quality of kale sprouts. Compared with the control and single treatments, combined BR and Suc application markedly increased chlorophyll and carotenoid levels, chlorophyll fluorescence parameters (qL, Y(II), F_v/F_m), sugar metabolism components (fructose, INVA, INVN, SSc, SSs), AsA-GSH cycle indicators (GSH, AsA/DHA), antioxidant enzyme activities (SOD, POD), and beneficial phytochemicals and nutrients (PAL, flavonoids, riboflavin, soluble sugars, cellulose, soluble protein, free amino acids). Conversely, it decreased levels of APX, DHAR, SPS, sucrose, glucose, AsA, DHA, and anthocyanins. Correlation analysis further identified key interactions between sugar metabolism and the AsA-GSH cycle, including sucrose with GSH and GSH/GSSG, GSSG with MDHAR, and fructose and INVA with AsA/DHA. These results indicate that BR and Suc co-treatment improves kale sprout growth and quality by elevating photosynthetic performance, antioxidant capacity, and the accumulation of health-promoting compounds. This studyprovides guidance for the combined application evaluation of plant hormones and carbon sources.