Physiologia plantarum最新文献

Valsa canker, a disease caused by necrotrophic fungi belonging to the genus Valsa, ranks among the most destructive pathogens jeopardizing the sustainable development of the pear and apple industries. The identification of resistance-related genes is therefore of great significance for advancing resistance breeding efforts and formulating effective disease control strategies. Receptor-like proteins (RLPs) are crucial membrane-localized sensors that play significant roles in diverse plant immunological processes. Still, the regulatory roles of RLPs in the Valsa canker resistance remain elusive. In this study, we found that a leucine-rich repeat receptor-like protein (LRR-RLP) gene, PbeRLP3, was highly induced by Valsa pyri in 'Duli-G03' (Pyrus betulifolia, a rootstock of pear) suspension cells. Overexpression of PbeRLP3 in 'Huangguan' pear (P. bretschneideri), 'Fuji' apple (Malus domestica) fruits, and 'Duli-G03' suspension cells significantly improved resistance to Valsa canker. However, the resistance contributed by PbeRLP3 was largely compromised by removing its Transmembrane (TM) region. RNA-seq and qRT-PCR analyses demonstrated that the expression of multiple genes associated with salicylic acid (SA), pattern-triggered immunity (PTI), and abscisic acid (ABA) pathways were induced in PbeRLP3-OE cells. Furthermore, Weighted Gene Co-Expression Network Analysis (WGCNA) displays that PbeRLP3 is co-expressed with 3 RLP genes and 17 Receptor-like kinase genes (RLKs). The results presented herein provide fresh insights into the effective screening of RLP genes related to resistance using specific molecular approaches, along with their application in follow-up molecular breeding strategies for boosting plant resistance.

SnRK1 protein kinases play a pivotal role in regulating plant development, growth signaling, and stress responses by managing cellular responses to energy fluctuations. SnRK1 activation was thought to depend mainly on the phosphorylation of threonine at position 175 (Thr175) within the activation loop. However, recent phosphoproteomic studies have identified additional phosphorylation sites. We explored the functional significance of these modifications, focusing on serine at position 176 (Ser176), adjacent to Thr175 in SnRK1α1. Our results reveal that dual phosphorylation of Ser176 and Thr175 is vital for optimal SnRK1 activity. Structural modeling and thermodynamic analyses highlight the critical role of these modifications in optimising substrate positioning and enzymatic efficiency. Furthermore, only the wild-type SnRK1α1, which can be phosphorylated at both sites, retains full functionality in in vivo experiments with yeast and Arabidopsis. Interestingly, pSer176 exhibits greater stability than pThr175 at various times throughout the day. Mutant proteins with substitutions at these sites (T175A/S176A mutants) accumulate in cytoplasmic aggregates after heat shock, suggesting a strong link between phosphorylation status, protein stability, and SnRK1 degradation pathways.

Atractylodes macrocephala Koidz., a perennial medicinal herb of the Asteraceae family, holds significant therapeutic value in traditional medicine. It is primarily recognized for its ability to strengthen spleen and stomach functions and modulate gastrointestinal activity. In this study, the molecular mechanisms governing sesquiterpenoid biosynthesis in A. macrocephala were investigated through an integrated sequencing strategy combining next-generation sequencing (NGS) and single-molecule real-time (SMRT) sequencing. Transcriptomic analysis identified 17,846 differentially expressed genes (DEGs) in rhizomes from three geographical origins, including 5196 upregulated and 12,650 downregulated genes. Nine full-length terpene synthase (TPS) genes were successfully retrieved. Comprehensive functional characterization of these AmTPS genes was performed using amino acid sequence analysis, multiple sequence alignment, phylogenetic reconstruction, quantitative real-time PCR (qRT-PCR), and heterologous expression assays. AmTPS8 and AmTPS9 were assigned to the TPS-a subfamily. Notably, AmTPS8 displayed the highest transcript abundance in samples from the Yuexi region, whereas AmTPS9 was most highly expressed in rhizomes from the Bozhou region. Enzymatic assays demonstrated that AmTPS8 catalyzes the formation of bulnesol, while AmTPS9 exhibits juniper camphor synthase activity. Overall, this study provides important insights into terpenoid biosynthesis in A. macrocephala and establishes a molecular basis for future research aimed at enhancing sesquiterpenoid production and elucidating regulatory mechanisms within this medicinally important species.

Understanding how plant roots manage co-occurring environmental stressors like nanoplastics (NPs) and arsenic (As) is critical, yet conventional methods often overlook their distinct strategic responses. Here, we developed and validated the Spatially-Dependent Interaction Framework (SDIF), a unified statistical model designed to deconstruct complex multi-stressor interactions across biological compartments. Applied to a high-resolution transcriptomic dataset from rice (Oryza sativa) co-exposed to environmentally relevant levels of NPs (1 mg L^-1) and As (1 mg L^-1 As(III)), our analysis revealed that roots employ a predominantly additive defense strategy, with virtually no significant nonadditive molecular interactions (1 gene). This contrasts sharply with the systemic response in leaves, where complex antagonistic interactions were prevalent (40 genes), indicating a distinct role in systemic damage control. Crucially, the SDIF's direct test for three-way interactions (Stressor A × Stressor B × Tissue) pinpointed the iron homeostasis protein Ferritin 1 (OsFer1) as a key regulator of this divergent strategy. OsFer1 exhibited synergistic amplification in roots (interaction log₂-fold change [LFC] = +1.27), consistent with a fortified frontline defense, which is reversed to an antagonistic suppression in leaves (LFC = -0.85). This critical finding, obscured by traditional analyses, highlights SDIF's utility in uncovering nuanced, organ-specific toxicodynamic strategies. It underscores the importance of a root-centric perspective for the risk assessment of contaminant mixtures in food crops.

Drought and insect herbivory constantly threaten yield and productivity of crops like soybean (Glycine max). Recent advances in crop science have examined these stressors either individually or sequentially, but concurrent interactions have not been well understood. Therefore, using two soybean cultivars (Blackhawk- drought susceptible and Magellan- drought tolerant), we investigated how concurrent drought and herbivory by the fall armyworm (Spodoptera frugiperda, FAW) affect soybean and FAW traits. Four treatments drought-D, herbivory-H, drought × herbivory-DH, and well-watered-WW were imposed at the third-trifoliate stage (V3) for a week. During the treatment period, daily measurements of net photosynthesis rate, stomatal conductance, transpiration rate, and soil moisture were taken, whereas plant height and chlorophyll content were recorded during alternate days throughout the treatment period. In addition, FAW mass gain was also measured daily. Leaf trichomes, a major physical defense system in plants, were estimated immediately post treatment and six days after. Our results showed that concurrent DH significantly impaired physiological traits, reduced the soil water content, and affected plant growth. Trichomes were significantly higher under DH compared to WW and the effect persisted after treatment. Although FAW performed similarly in both drought-stressed and well-watered plants, strong cultivar effects were observed for larval mass gain and FAW seemed to perform better on the drought susceptible cultivar. This study established a clear trend showing drought is the dominant stressor on soybeans, compared to herbivory alone and hence informs the growers for prioritization of stress management. Overall, this study presents novel insights into the effects of concurrent drought and herbivory, with implications for resistance breeding using tolerant cultivars against stressors like herbivory and drought.

The epidermal and inner tissues of stem organs adhere via the cell wall, and the adhesion of both tissues is involved in the structural integrity of the stem. We have developed a method to quantitatively measure adhesive strength between these tissues. In this study we examined the effects of white light on adhesive strength between epidermal and inner tissues of pea epicotyls, as well as the chemical properties of cell walls in both tissues. The irradiation of white light to etiolated seedlings resulted in significantly higher adhesive strength between epidermal and inner tissues, as well as inhibition of elongation growth of the epicotyls. Further observation of epicotyl cross-sections revealed that white light substantially increased the intensity of autofluorescence emitted from the cell wall in epidermal tissue and the outermost layer of inner tissue, accompanied by color alteration. Overall, the spectrum of the autofluorescence emitted from light-irradiated epicotyl sections matched that of reference standard p-coumaric acid, a phenolic acid. Further chemical analysis of cell wall constituents revealed that cell wall-bound p-coumaric acid was predominantly accumulated in epidermal tissue in response to light irradiation. Taken together, these results suggest that light-induced accumulation of cell wall-bound p-coumaric acid in epidermal tissue may enhance the adhesive strength between epidermal and inner tissues. Moreover, increased adhesive strength between these tissues may contribute to light-induced inhibition of pea epicotyl elongation.

Pepper root rot, caused by Fusarium solani, is a destructive disease that leads to significant yield losses in pepper crops. In this study, strain Yao was isolated from pepper rhizospheric soil and identified as Bacillus velezensis based on morphological, physiological, biochemical, and molecular characteristics. Strain Yao exhibited strong antagonistic activity against F. solani in dual culture, causing fungal hyphae to be fractured, wrinkled, and shrivelled. In greenhouse pot experiments, strain Yao significantly decreased the incidence of pepper root rot, achieving a controlled efficacy of 73.79%, which was associated with increased activities of the defence-related enzymes (CAT and POD) and enhanced levels of osmotic adjustment substances (free proline, soluble protein, and soluble sugar). Additionally, strain Yao promoted pepper seedling growth by increasing plant height, stem thickness, and both fresh and dry weight, while also improving photosynthetic parameters (Pn, Tr, and Gs) and fluorescence parameters (qP, ETR). Lipopeptides produced by strain Yao, identified through high-performance liquid chromatography (HPLC) and MALDI-TOF MS, revealed fengycin as the main antagonistic metabolite inhibiting fungal hyphae growth. Transcriptome sequencing revealed that differentially expressed genes were primarily enriched in plant hormone signal transduction and the MAPK signaling pathway. Strain Yao induced resistance-related genes, eliciting pepper PTI and ETI defence systems, subsequently challenging F. solani. Overall, B. velezensis Yao shows great potential as a biological control agent (BCA) for managing pepper root rot and as a plant growth-promoting bacterium (PGPB).

Drought stress is one of the important abiotic constraints that limit plant growth and crop productivity. This paper shows that the expression of an O-methyltransferase gene from Peucedanum praeruptorum Dunn improved the drought tolerance of Arabidopsis. Transgenic lines exhibited superior physiological phenotypes compared to wild-type (WT) plants under drought stress, as evidenced by increased root length, biomass, leaf water content, and reduced water loss. Enzyme activity assays revealed that transgenic lines exhibited stronger antioxidant responses than WT seedlings under drought stress. Significantly improved activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were observed. Concurrently, increased total glutathione (T-GSH) content and reduced malondialdehyde (MDA) levels indicated alleviated oxidative damage. Furthermore, compared to WT plants, the transgenic lines exhibited enhanced proline (PRO) and chlorophyll contents, which suggest improved osmotic regulation capacity and photosystem integrity under drought stress. Quantitative PCR experiments demonstrated that overexpression of PpCOMT-S induced the timely expression of drought-responsive genes, including AtNHX1, AtAVP1, AtKT1, AtMnSOD, AtPOD, AtAPX1, and AtP5CS2. Surprisingly, PpCOMT-S overexpression reprogrammed coumarin metabolic flux in Arabidopsis, which enhanced the accumulation of scopoletin and the tolerance of seedlings to drought stress. Our findings suggest that PpCOMT-S is a multi-functional regulator that increases drought tolerance through improved water retention, antioxidant capacity, osmotic adjustments, expression of stress-related genes, and coumarin-mediated reprogramming of metabolism.

In legumes, flowering time is regulated by genes responsive to temperature and photoperiod, presenting challenges for high-latitude lentil producers who must adapt cultivars to short growing seasons and extended daylight hours. Therefore, prolonged vegetative periods are favored in those areas. To address this, we studied a recombinant inbred line (RIL) population, derived from a cross between the adapted cultivar CDC-Milestone and the non-adapted line ILL8006, to investigate phenology-related traits under long-day conditions in western Canada. Significant variation in days to emergence (DTE), days to flowering (DTF), and days to pod maturity (DTM) enabled analysis of the vegetative (VegP) and reproductive (RepP) periods within the population. We constructed a high-density genetic linkage map using molecular markers linked to genes in the Lcu.2RBY reference genome, identifying quantitative trait loci (QTLs) for those traits across four site-years in Saskatchewan. Differential expression analysis of known flowering time genes enhanced interpretation of the QTL results for flowering time. Three major DTE QTLs (qDTE2/3.II, qDTE2/3.III, and qDTE2/3.IV) on chromosome 2 explained 16%-28% phenotypic variability, depending on the environment, with in silico analysis identifying six curated genes as putative candidates within that region. A key DTF QTL (qDTF6.I) on chromosome 6 accounted for 23%-56% of phenotypic variability, harboring a homolog of the FLOWERING LOCUS T gene, whose role was explored alongside other candidate genes. Dissecting the vegetative period into DTE and DTF revealed distinct genetic controls for each trait, enabling breeders to combine early or late emergence and flowering to optimize adaptation and yield in diverse agroclimatic conditions.

Drought and salinity are significant challenges to tomato production under climate change. A 2-year experiment (2023-2024) with Solanum lycopersicum cv. Resi evaluated the effects of drought (25%, 12.5%, and 6.25% of soil weight) and salinity (0.5% and 1.0% NaCl), applied individually and in combination, on yield, mineral uptake, and secondary metabolism. Drought reduced yield by 28%, salinity by 17%, and their combination by 27%. Moderate drought and salinity increased potassium (K⁺) uptake, whereas severe stress reduced calcium (Ca²⁺) concentration and disrupted overall ionic homeostasis. Lycopene and β-carotene decreased under combined stress, whereas chlorogenic acid and naringenin chalcone increased, indicating enhanced antioxidant metabolism. Antioxidant activities (TEAC, DPPH, and TPC) rose under moderate stress, particularly in the warmer 2024 season. Correlation analysis showed that magnesium (Mg²⁺) accumulation was positively associated with antioxidants and carotenoids, supporting redox balance under stress conditions. Overall, these findings indicate that tomato adaptation to drought and salinity relies on coordinated ionic regulation and antioxidant adjustments, both influenced by environmental conditions.