Physiologia plantarum最新文献

Brassinosteroids (BRs), a class of essential plant steroid hormones, have emerged as central regulators in optimizing crop architecture, yield potential, and nutrient use efficiency (NUE). Through crosstalk with gibberellin (GA), auxin (IAA), strigolactone (SL), and nitrogen (N) signaling pathways, BRs coordinate cell elongation, tillering, and nutrient assimilation to optimize growth-resource balance. Allelic variations affecting BR biosynthesis or perception often generate compact, erect-leaf plant types suited for dense planting and enhanced lodging resistance-key traits for high-yield ideotypes. This review outlines BR signaling networks and crosstalk with GA, IAA, SL, and N pathways in cereals. Two principal regulatory hubs are emphasized: the Zinc Finger protein (ZnF)-BRASSINOSTEROID INSENSITIVE1 KINASE INHIBITOR1 (BKI1)-BRASSINOSTEROID INSENSITIVE1 (BRI1) receptor module, which fine-tunes BR perception and determines architectural traits, and the GLYCOGEN SYNTHASE KINASE 2 (GSK2)-BRASSINAZOLE-RESISTANT1 (BZR1)-DWARF AND LOW-TILLERING (DLT)-SMALL ORGAN SIZE1 (SMOS1)-GROWTH-REGULATING FACTOR4 (GRF4)-DELLA regulatory module, which integrates BR signaling with GA responsiveness and nitrogen metabolism. Moreover, deletion of the "r-e-z" haploblock, encompassing Rht-B1b, EamA-B, and ZnF-B, elicits a semi-dwarf phenotype with 6.48%-15.25% yield increases. These interconnected networks establish a molecular framework for engineering BR-driven cereal ideotypes. Future breeding could improve resource efficiency by fine-tuning BR activity in shoots for compact growth and promoting it in roots for enhanced nutrient uptake. Integrating genomics and precision gene editing will enable fine-tuning of BR signaling intensity and its crosstalk with other hormonal and nutrient pathways. By prioritizing growth optimization over mere growth maximization, BR-based strategies offer a sustainable path toward high-yield, nitrogen-efficient cereal production.

Soil contamination by bisphenol A (BPA) has raised considerable ecological and environmental concerns, particularly due to its potential impact on plant growth. However, the interactive effects of BPA and different soil types on soil-plant systems remain poorly understood. Capsicum annuum L., a widely cultivated vegetable crop, was used as a model to systematically investigate the mechanisms of BPA uptake, translocation, and metabolic disruption in roots under varying soil types and BPA dose. Greenhouse experiments showed that BPA accumulation in pepper roots was highest in viscous soil, significantly greater than in sandy or loamy soils. When BPA dose exceeded 10 mg kg^-1, root elongation and vitality were markedly suppressed, accompanied by enhanced antioxidant enzyme activity and elevated malondialdehyde content, indicating phytotoxicity was linked to increased oxidative stress. Integrated transcriptomic and metabolomic analyses identified 995 differentially expressed genes and revealed significant disruptions in root metabolic processes. BPA exposure altered the expression of genes related to the biosynthesis of phytohormone precursors and branched metabolites. Key pathways, including indole-3-acetic acid biosynthesis and phytohormone signal transduction, were significantly affected. These findings clarify the soil-dependent uptake and translocation patterns of BPA in pepper roots and provide important molecular insights into the plant's adaptive and defense responses to BPA-induced stress.

Strigolactones (SLs) are phytohormones derived from carotenoids that influence various aspects of plant growth, development, and the ability of plants to respond to environmental changes and microbial interactions. Initially categorized as shoot branching inhibitors, SLs are now recognized as crucial rhizospheric signaling molecules that govern nutrient availability, hormonal control, and microbial interactions. Despite significant progress in SL biology, a cohesive synthesis connecting SL molecular signaling, rhizosphere communication, and stress tolerance remains fragmented, hindering their practical use in sustainable agriculture. A more comprehensive understanding of their synthesis process (D27-CCD7/8-MAX1-CLA cascade), their perception (D14-MAX2-SMXL module), and the impact of SMXL7 on chromatin has revealed significant implications on physiology. To enhance plant development under stress conditions, SLs drive auxin transport, regulate ABA-dependent stress signaling, influence the antagonistic effects of cytokinins, and coordinate gibberellin activity with the circadian rhythm. SLs augment arbuscular mycorrhizal colonization, stimulate nodulation, and attract plant growth-promoting rhizobacteria through chemotactic and metabolic interactions. Using GR24 and SL-conjugated nanomaterials enhances plant resistance to drought, salt, and metal stress. Modifying SL-transporters with CRISPR improves SL signaling and fosters beneficial symbiotic associations. The study is crucial because it underscores the importance of SLs in recruiting beneficial microorganisms and facilitating microbial-hormonal interactions. This review proposes a cohesive conceptual framework that integrates receptor specificity, rhizospheric sensing, and microbial response, beyond mere descriptive synthesis. It sets distinct research targets, such as receptor-specific SL-analogues, in situ sensing techniques, and tailored SL-responsive microbial consortia, to make biostimulation more precise and assist crops in withstanding climatic stress more effectively.

Tetrastigma hemsleyanum Diels et Gilg (T. hemsleyanum) is a plant of considerable medicinal and economic value. However, the molecular mechanisms underlying its tuberous root formation remain poorly understood. To investigate the molecular basis of tuberous root formation, we analyzed hormonal metabolic levels, transcriptomic profiles, and root anatomical changes during this process. Using ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry, we quantitatively assessed the levels of eight plant hormones and their derivatives in the early stages of tuberous root formation and in adventitious roots. The results revealed significant fluctuations in hormone levels, with a marked upregulation of cytokinins (tZ, DZ, and IP) and the complete absence of gibberellin GA₁ post-tuberous root formation. Jasmonic acid content decreased, while methyl jasmonate (MeJA) increased substantially. Exogenous application of MeJA further confirmed the role of the jasmonic acid pathway in tuberous root formation, underscoring the pivotal role of these hormones in root differentiation and expansion. Additionally, transcriptomic analysis identified significant alterations in biological processes associated with the cytoskeleton and cell wall during tuberous root formation. Anatomical observations indicated reduced lignification and a notable increase in vascular cambium and xylem parenchyma cells. In conclusion, this study provides valuable insights into the molecular mechanisms of tuberous root formation in T. hemsleyanum, emphasizing the critical role of plant hormones and offering new strategies for enhancing tuber growth and yield through hormonal regulation.

The ubiquitin-proteasomal protein degradation system is a key regulatory process mediating the dehydration stress response in plants, and RGLG proteins, a subfamily of the RING E3 ligases, are well known to modulate this response. In this study, we isolated four SlRGLG proteins (Solanum lycopersicum RING domain ligase) from tomato plants and characterized their functions at the molecular and biological levels. We found that these four SlRGLGs have the conserved VWA and RING domains and high amino acid sequence identities with RGLGs from Arabidopsis thaliana and pepper plants. The transcript levels of SlRGLGs were found to be responsive to several environmental stimuli, including dehydration, mannitol, and abscisic acid, which are believed to be associated with the presence of different stress-associated cis-regulatory elements in the respective promoter regions. Subcellular localization studies of SlRGLGs-GFP fusion proteins revealed distinct subcellular distribution patterns, and all four MBP-SlRGLGs recombinant proteins exhibited robust E3 ligase activities in vitro. To elucidate their biological roles in the dehydration stress response, we generated SlRGLGs-silenced tomato plants and SlRGLGs-overexpressing (OE) Arabidopsis plants. Notably, all SlRGLGs-silenced tomato plants were found to have dehydration-sensitive phenotypes with increased transpirational water loss and lipid peroxidation of cell membranes and decreased expression of dehydration stress-responsive genes. However, all SlRGLGs-OE Arabidopsis plants showed the dehydration-tolerant phenotypes, compared to control plants. Collectively, these findings indicate a positive role for all four SlRGLGs in the dehydration stress response of tomato.

Moso bamboo (Phyllostachys pubescens), a fast-growing and potentially invasive species, exhibits culm-age heterogeneity in structure and physiology; however, its water-use strategies in relation to aging remain unclear. Thus, we aimed to examine age-related variations in hydraulic performance, vessel integrity, and nutrient allocation in bamboo culms aged 1-5 years. Sap flux density peaked in 2-year-old culms, possibly reflecting the maturation of conductive tissues. However, daily sap flow rates showed no significant age-dependent differences. Dye tracing and cryo-scanning electron microscopy revealed consistent axial and radial vessel continuity and low embolism frequency across all age groups, with a relative loss of potential conductivity of approximately 10%. Elemental analysis showed reduced K concentration and delayed Si accumulation in the vessel sap with age, suggesting a physiological shift from osmotic regulation to structural reinforcement. Starch began accumulating in the third year and peaked at age four, indicating a physiological transition from resource consumption to energy storage. These coordinated transitions support sustained water transport across ages and may enhance resilience under drought and interspecific competition. Our findings revealed functional plasticity in water use and resource allocation during culm development, highlighting the physiological mechanisms that may underlie the ecological success and invasive potential of Moso bamboo.

Phosphorus (P) deficiency and water deficit are major constraints to soybean yield worldwide. While their individual impacts are well established, little is known about how P deficiency modulates soybean recovery from recurrent water stress. This study evaluated the effects of P deficiency on the recovery capacity of two soybean cultivars, contrasting in drought sensitivity, during the grain-filling stage. Plants were grown under either high P availability or P deficiency and subjected to different irrigation regimes: well-watered (WW), severe water deficit at R5 (WS-R5), and moderate deficit at V5 followed by severe deficit at R5 (WS-V5 + R5). The experiment followed a randomized complete block design in a 2 × 3 factorial scheme. Under water stress, P deficiency delayed stomatal resistance, extending photosynthetic decline in both cultivars. However, recovery of photosynthetic rate and stomatal conductance was faster under P deficiency than under high P supply. In the sensitive cultivar, P deficiency enhanced memory-mediated recovery of photosynthesis only after two stress cycles, with compensatory increases in mesophyll conductance, decreasing mesophyll limitations and favoring recovery. In contrast, the tolerant cultivar showed stable photosynthetic responses regardless of P level, with similar recovery in light saturation and photorespiration. Grain composition was affected by P deficiency in both cultivars, with lower protein concentration and increased oil content, particularly of unsaturated fatty acids. These results indicate that P deficiency alters physiological adjustments in soybean genotypes sensitive to water deficit, influencing their capacity to recover from recurrent drought stress and affecting grain quality.

Powdery mildew (PM) is one of the major diseases in pumpkin cultivation. However, the molecular mechanism of epigenetic regulation in pumpkin defense against PM is still unclear. This study integrated physiological, methylome, and transcriptome analyses of Cucurbita moschata leaves infected with Phytophthora xanthii. PM infection significantly increased the MDA content and CAT, POD, and SOD activities in pumpkin leaves, while reducing protein and chlorophyll content. Global DNA methylation decreased in P. xanthii-infected plants, with prominent hypomethylation at CHH contexts in promoter regions. The analysis of methylome and transcriptome identified 2668 differentially methylated genes (DMGs) and 2356 differentially expressed genes (DEGs), respectively. GO functional annotation and KEGG pathway enrichment analyses revealed that DMGs and DEGs were primarily involved in antioxidant, photosynthesis, and metabolism. A correlation analysis between promoter DNA methylation level and gene expression identified 160 negatively correlated genes, which included members involved in photosynthesis, lipid metabolism, antioxidant responses, transcription factors, and methyltransferases. We further confirmed the function of CmERF098 as a nuclear transcription factor. RT-qPCR analysis revealed that the CmERF098 gene responds to both PM stress and MeJA treatment. In C. moschata, overexpression of CmERF098 conferred resistance to PM by reducing MDA content while enhancing POD activity as well as chlorophyll and protein content. Additionally, overexpression of CmERF098 suppressed the JA signaling pathway via downregulation of CmMYC2 and CmJAR1. These findings provide novel insights into the molecular mechanisms underlying epigenetic regulation and provide new candidates to incorporate in breeding for disease-resistant pumpkins.

Chicory roots produce inulin, a dietary fiber, as well as large quantities of bitter sesquiterpene lactones (STLs), which have valuable biological activities. In an effort to understand the compartmentalization of metabolism within chicory roots and the molecular basis of the development of laticifers that produce the chicory latex, we performed metabolomics and transcriptomics profiling of different tissues of chicory roots. Gas chromatography coupled to mass spectrometry (GC-MS) and liquid chromatography coupled to mass spectrometry (LC-MS) identified a total of 21,437 features, of which 135 were differentially abundant between cell types. Further analysis indicated that the major STLs accumulated primarily in the latex. Gene expression of known STL pathway genes indicates a compartmentalization of the biosynthesis across multiple tissues, with implications regarding the trafficking of pathway intermediates. Phytohormone measurements and gene expression analysis point to a major role for jasmonate signaling in the development and differentiation of laticifers. Furthermore, inulin accumulates mostly outside the laticifers, but expression of inulin metabolic genes also points to a complex distribution and trafficking of inulin or inulin precursors across different root compartments. Altogether, the data presented here constitute a unique resource to investigate several biological processes in chicory roots, including laticifer development, STL biosynthesis and transport, and inulin biosynthesis regulation.