Physiologia plantarum最新文献

Larch (Larix spp.), a key species in China's reforestation efforts, faces increasing threats from shoot blight caused by Neofusicoccum laricinum. This study characterized the biological traits, virulence mechanisms, and host interactions of this pathogen to inform disease management. Twenty-five N. laricinum strains were isolated from six regions in Northeast China and identified through morphological and molecular analysis. Comprehensive growth assessments revealed optimal development at 18°C and pH 9-11, with significant strain-specific variation in virulence (lesions 18.4-38.8 mm). Pathogenicity assays revealed that the hypervirulent TM02 strain exhibited early and robust production of cell wall-degrading enzymes, such as pectin methylgalacturonase (PMG, 208.9 U/mg) and polygalacturonase (PG, 54.9 U/mg), correlated with its aggressive infection phenotype. Biochemical analyses revealed that the pathogen actively disrupted host oxidative defenses, with superoxide dismutase (SOD) activity peaking at 3 dpi (456.7 U/g/min) before decreasing to 0.8× control levels by 7 dpi, whereas peroxidase (POD) activity exhibited a transient 4.6-fold increase followed by rapid suppression. Transcriptome analysis revealed generally downregulation of defense genes, mainly cellulose synthase (21/25 genes) and peroxidase (38/45 genes), with 10.5-fold inhibition of Ces-g8671 and 11.4-fold reduction in Pod-g18614 expression, indicating that pathogens can simultaneously damage larch cell wall synthesis and the ROS scavenging defense system. These findings establish N. laricinum's sophisticated two-phase infection strategy: initial physical breach of cell walls facilitated by CWDEs, followed by systematic suppression of host antioxidant defenses. This study identifies specific molecular targets for developing intervention strategies and provides critical insights into host-pathogen dynamics in larch plantations under climate change scenarios.

Verticillium wilt, primarily caused by Verticillium dahliae, represents a major constraint on both quality and yield in upland cotton (Gossypium hirsutum). Calcium (Ca²⁺) functions as a pivotal second messenger in plant signal transduction, regulating the expression of stress-induced genes. The Soybean gene Regulated by Cold-2 (SRC2), which encodes a protein containing C2 domains, is known to play important roles in plant development and environmental adaptation. In this study, a total of 31 SRC2 members were identified in five cotton species and classified into five distinct groups. Analyses of gene structure and conserved protein motifs revealed that SRC2 genes are evolutionarily conserved. GhSRC2 genes were widely expressed in various cotton tissues and showed responsiveness to cold, heat, drought and salt stresses. Notably, GhSRC2-3D expression was significantly induced upon V. dahliae infection. Subcellular localization assays indicated that GhSRC2-3D localizes to the cell membrane. Complementation of Arabidopsis src2 mutant with GhSRC2-3D restored resistance to V. dahliae, while a C2 domain deletion variant (ΔGhSRC2-3D) failed to confer resistance. Furthermore, down-regulation of GhSRC2-3D mediated by virus-induced gene silencing (VIGS) compromised V. dahliae resistance in upland cotton. Collectively, our findings demonstrate the conserved role of GhSRC2-3D in plant defense against V. dahliae infection and underscore the essential contribution of its C2 domain to protein function.

Abscisic acid (ABA) plays a crucial role in plants' adaptation to drought and salinity. This study used Y2H (Yeast two-hybrid system), GST pull-down, and LCI (Firefly luciferase complementation imaging assay) approaches to reveal the role of the interaction between OsAE7 (asymmetric leaves1/2 enhancer 7) and ZFP36 (zinc finger protein 36) in rice. Subcellular localization analysis revealed that OsAE7 is localized in the nucleus. After treatment with ABA, H₂O₂, osmotic stress (polyethylene glycol, PEG), and NaCl, the expression level of OsAE7 genes in leaves has increased. Experiments with H₂O₂ scavenger (DMTU) and NADPH oxidase inhibitor (DPI) indicated that ABA induces the up-regulation of OsAE7 expression through increased ROS production. The OsAE7 gene knockout mutant osae7-KO was constructed using the CRISPR/Cas9 system and Agrobacterium-mediated method, and T₁ generation homozygous lines osae7-1 and osae7-2 were obtained. Under simulated stress with PEG and NaCl, the antioxidant defense enzyme activity, relative water content, and proline content of the osae7-KO mutant were significantly lower than those of the wild type, while the malondialdehyde content and relative plasma membrane permeability were significantly higher, indicating that the osae7-KO mutant has lower stress resistance. osae7-KO plants were also much less sensitive to ABA than the wild type. qRT-PCR analysis showed that the interaction with ZFP36 affects the induction of OsAE7 by ABA. In conclusion, OsAE7 is involved in the ABA signaling pathway and plays a role in the plant's response to drought and salt stresses.

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.

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.

Plants are constantly exposed to sound vibrations (SVs) from different sources, which have a significant impact on their growth and adaptation. However, how plants perceive and respond to SVs remains largely unknown. In this study, we examined the early biochemical signaling events, like reactive oxygen species (ROS) and hormonal dynamics, in Arabidopsis after 30 and 60 min of specific single-frequency SV treatments (500 Hz, 100 dB). Our results showed that SV triggers ROS production after 30 and 60 min treatment as compared to non-SV treatment plants. To further confirm, we evaluated the transcript levels of 10 respiratory burst oxidase homologs (RBOHs) in Arabidopsis after SV treatment. Our results showed that SV treatment significantly increased the expression of RBOHA, RBOHD, and RBOHF, while SV downregulates RBOHE, RBOHG, RBOHH, and RBOHJ at both time points. However, SVs have no effect on the transcript of RBOHC and RBOHI at both time points. Further, we examine the effect of SVs on plant hormones like salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), auxin (AUX), gibberellic acid (GA), cytokinin (CY), and brassinosteroid (BR), and their marker genes. Based on the LC-MS/MS quantification assay and real-time PCR analysis, SV treatment increases SA, JA, CY, and GA levels while decreasing ABA, IAA, and BR. These results revealed that SV mechanosignals trigger early biochemical signaling events like ROS and hormones, which can regulate subsequent key signaling cascades involved in SV signal transduction.

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.