Plant signaling & behavior最新文献

To increase yield and productivity, plants are treated with chemicals; however, these interventions have inadvertently contributed to a decline in food security. To mitigate these challenges, plant growth-promoting rhizobacteria (PGPRs), which increase yield, have been widely used to modulate plant immunity. Some PGPRs have recently been reported to exhibit opportunistic pathogenicity in humans, raising safety concerns regarding their widespread application. Membrane vesicles (MVs) derived from PGPR may retain similar plant growth-promoting (PGP) traits and thus could aid in plant protection. This research tests the hypothesis that MVs derived from the PGPR Priestia megaterium VIT-2021 as an effective and sustainable alternative for combating bacterial infection. MVs were successfully isolated and characterized, and the results ensured that these MVs are efficient antimicrobial agents against Pseudomonas syringae. Proteomic analysis of the MVs revealed the presence of four antimicrobial peptides AMP underlying their antimicrobial effects. Furthermore, in vitro treatment with these MVs downregulated P. syringae virulence genes, including avrE, hrpS, and mgrA. In planta experiments conducted on Oryza sativa demonstrated that P. megaterium MVs effectively reduced P. syringae pathogenicity through immune modulation, as evidenced by the upregulation of WRKY13, IPA1, WKRY45, NPR1 and PR1, with fold increase of approximately 2.98, 3.55, 1.73, 2.44, and 5.51, respectively, at 4.2 × 10⁸ particle concentration. WRKY13 is involved in SA-mediated secondary cell wall synthesis, which resists pathogen ingress. Increased IPA1 promoted the upregulation of WRKY45, which could contribute to SA-mediated antimicrobial secondary metabolite synthesis. Increased expression of NPR1 and PR1 mediate cell wall rigidification and antimicrobial activity, ultimately contribute to robust immunity. Additionally, increased IPA1 is associated with multiple tiller outgrowths, panicle branching, and grain size development. Thus, P. megaterium MVs demonstrated dual functionality of immunomodulation and growth promotion in O. sativa. Therefore, the current research highlights a pioneering strategy for sustainable crop protection and yield enhancement.

CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1), originally identified in Arabidopsis thaliana, encodes a pattern recognition receptor that perceives the fungal cell wall component called chitin to activate immune responses, including the production of reactive oxygen species (ROS) against fungal pathogens. Functional CERK1 orthologs have been identified in plants, such as tomato, rice, and wheat. However, the knowledge of chitin-triggered immunity in Cucurbitaceae plants is currently limited. This study revealed that chitin triggers ROS generation in melon (Cucumis melo) and cucumber (Cucumis sativus), indicating that chitin is recognized by cucurbits. A subsequent homology search using the Arabidopsis CERK1 sequence identified CERK1 ortholog candidates of melon (CmCERK1) and cucumber (CsCERK1). Virus-induced gene silencing of CmCERK1 severely reduced chitin-triggered ROS generation in melon, indicating that CmCERK1 is essential for chitin recognition and the subsequent immune response. Genomic PCR of CmCERK1 and ROS assay upon chitin treatment in multiple melon commercial cultivars also showed that functional CmCERK1 is conserved in all the tested cultivars. Further analysis of the available genomes of various cucurbit plants suggested that CERK1 is broadly conserved in cucurbit plants.

Kin selection theory predicts that closely related organisms may exhibit cooperative behaviors that enhance group fitness despite individual costs. In contrast, the resource partitioning hypothesis posits stronger competition among close relatives due to shared resources and niche overlap. In this study, we tested whether quinoa (Chenopodium quinoa Willd) genotypes differ in performance when grown with kin versus non-kin under different soil fertility and heavy metal toxicity conditions. A two-level, three-factorial experimental design was conducted, including kinship, fertility, and toxicity. Biomass accumulation, allocation patterns, resource acquisition traits, and photosynthetic parameters were measured at the end of the experiment. Kinship and fertility effects were common, but toxicity effects were rare. Biomass accumulation was greater in more fertile soils, and kinship marginally increased biomass. Root allocation was affected by toxicity interactions: kin plants showed greater root allocation under no-toxicity conditions, but this difference was suppressed under metal toxicity. Resource acquisition traits reflected these patterns, with specific taproot length and average leaf mass being higher for kin combinations, while specific stem length and specific leaf area were higher for non-kin combinations. The net assimilation rate, stomatal conductance, transpiration rate, and WUEi were generally higher in non-kin than in kin plants, regardless of soil fertility. These results suggest that quinoa plants may benefit from kin interactions through increased root growth and overall biomass accumulation, but metal toxicity suppresses these benefits, showing that kinship advantages are context dependent and reduced in contaminated soils.

Fibrillins (FBNs) are conserved plastid lipid-associated proteins involved in lipid storage, stress adaptation and plastid ultrastructure. While several Arabidopsis thaliana FBNs have been functionally characterized, the biochemical properties of the thylakoid-associated FBN3a remain poorly understood. AlphaFold modeling revealed that AtFBN3a adopts an eight-stranded β-barrel fold typical of the lipocalin family, with high-confidence predictions for the core β-strands and conservation of the structurally conserved region 1 (SCR1) motif that stabilizes the barrel and defines the ligand-binding cavity. This structural topology is also shared with AlphaFold models of the other members of the family in A. thaliana. Consistent with the lipocalin-like structural and sequence features, protein-lipid overlay assays showed that AtFBN3a bound the anionic plastid lipids phosphatidic acid and sulfoquinovosyl diacylglycerol, but not phosphatidylcholine. Additional assays revealed a clear preference for saturated fatty acids, with stronger binding to long-chain saturated species. Together, these findings identify AtFBN3a as a lipocalin-like domain-containing protein with selective affinity for saturated fatty acids, suggesting a conserved role for FBNs in plastid lipid metabolism and stress adaptation.

Starch metabolism in plants involves a complex network of interacting proteins that work together to ensure the efficient synthesis and degradation of starch. These interactions are crucial for regulating the balance between energy storage and release, adapting to the plant's developmental stage and environmental conditions. Several studies have been performed to investigate protein-protein interactions (PPIs) in starch metabolism complexes, yet it remains impossible to unveil all of the PPIs in this highly regulated process. This study uses yeast-two-hybrid (Y2H) screening against the Arabidopsis leaf cDNA library to explore PPIs, focusing on the starch-granule-initiating protein named Protein Targeting to Starch 2 (PTST2, At1g27070) and the protein involved in starch and maltodextrin metabolism, namely, plastidial phosphorylase 1 (PHS1, EC 2.4.1.1). More than 100 positive interactions were sequenced, and we found chloroplastidial proteins to be putative interacting partners of PTST2 and PHS1. Among them, photosynthetic proteins were discovered. These novel interactions could reveal new roles of PTST2 and PHS1 in the connection between starch metabolism and photosynthesis. This dynamic interplay between starch metabolism and other chloroplast functions highlights the importance of starch as both an energy reservoir and a regulatory component in the broader context of plant physiology and adaptation.

Drought-induced osmotic stress is a significant constraint to soybean growth and yield, necessitating the development of effective mitigation strategies. Silicon acts as an important strategy to mitigate the negative stress effects of drought stress. The study was aimed to evaluate the potential of soil-applied silicon in alleviating drought stress in soybean. Two field capacities were tested: control (85% FC) and drought (50% FC), with four silicon application rates (0, 100, 200, and 300 kg ha^-1) applied at sowing. Drought stress significantly affected the morphological parameters in soybean as plant height, leaf area, and water potential were reduced by 25%, 20%, and 36%, respectively, while root length increased as compared to control-85% FC. However, drought stress reduced root density, surface area, and biomass as compared to control-85% FC. Additionally, drought reduced photosynthetic rates, chlorophyll a and b levels, and stomatal conductance, while increasing malondialdehyde and hydrogen peroxide. The natural plant defense system was upregulated, with increased activity of phenolics, soluble proteins, and antioxidant enzymes like catalase, superoxide dismutase, and peroxidase. However, silicon applications, especially at 200 kg ha^-1, significantly alleviated the negative effects of drought stress by improving morphophysiological and biochemical traits in soybeans. Compared to the control, Si₂₀₀ increased plant height, root length, photosynthetic rate, and water potential by 22%, 39%, 23%, and 17%, respectively, as compared to control. Furthermore, silicon reduced malondialdehyde and hydrogen peroxide levels by 21% and 10%, enhancing plant resilience. Silicon supplementation also boosted biochemical attributes, with total soluble proteins, phenolics, and antioxidant enzyme activities increasing by 30%, 55%, 19%, 24%, and 31%, respectively, under drought conditions. In crux, silicon at 200 kg ha^-1 effectively mitigated the effects of drought stress in soybean, becoming a more sustainable approach to sustain crop yield and food security.

Bupleurum chinense DC. a medicinal plant valued for saikosaponins (SSs) with antipyretic and hepatoprotective properties, faces constrained SS biosynthesis mediated by abscisic acid (ABA) during growth. Basic helix-loop-helix (bHLH) transcription factors (TFs) are hypothesized to participate in ABA signaling cascades, but their mechanistic role in SS regulation remains undefined. In this study, 20 differentially expressed BcbHLH genes were identified by transcriptomic profiling of ABA-induced hairy roots, with four MYC-family candidates (BcbHLH1-BcbHLH4) demonstrating ABA-responsive regulatory potential. ABA exposure (100 or 200 μmol/L, 24-72 h) induced dose-dependent SS reduction, while correlation analyses revealed coordinated expression between BcbHLH1-BcHMGR (r = 0.62) and BcbHLH4-BcBAS (r = 0.78), pinpointing these TFs as critical nodes in SS pathway modulation. Tissue-specific profiling showed predominant BcbHLH expression in stems and young leaves, with nuclear localization confirming their transcriptional regulatory organelles. BcbHLH3/4 exhibited transcriptional activation activity in the MYC_N domain, while molecular docking predicted 11th Arginine in the HLH domain as essential for G-box DNA binding. Collectively, our findings suggest that BcbHLH1-BcbHLH4 may serve as potential switches for fine-tuning ABA responsiveness in SS biosynthesis. Strategic manipulation of BcbHLH activity through genetic engineering approaches such as CRISPR-based editing or overexpression could alleviate ABA-mediated biosynthetic repression. Furthermore, precision engineering of the critical functional domain in BcbHLH could enhance promoter-binding activity to target genes and improve SS biosynthesis efficiency. These findings provide a reference framework for harnessing transcriptional regulators to optimize SS production in Bupleurum chinense DC.

TiO₂ nanomaterials can promote plant growth and enhance disease resistance. However, the underlying mechanism remains unclear. This study applied TiO₂ to promote the growth of wheat, soybean, tobacco, cucumber, and corn. Genetic analysis using macro-element transporter rice mutants in rice revealed that growth promotion induced by TiO₂ was dependent on potassium transporter (AKT1), nitrate transporter 1.1B (NRT1.1B), ammonium transporter 1 (AMT1), and phosphate transporter 8 (PT8). TiO₂ also enhanced chlorophyll accumulation, and growth promotion was inhibited in the chlorophyll biosynthesis rice mutants, yellow-green leaf 8 (ygl8) and divinyl reductase (dvr), indicating that TiO₂ promoted growth through chlorophyll biosynthesis. In addition to photosynthesis, TiO₂ affected light signaling by inhibiting the translocation of Phytochrome B (PhyB) from the cytosol to the nucleus, thereby improving resistance to rice sheath blight (ShB). TiO₂ application also enhanced resistance to wheat stem rust, tobacco wildfire, angular spot disease, and rice ShB by inhibiting the growth of bacterial and fungal pathogens, suggesting that TiO₂ regulates plant defense signaling and has antibacterial and antifungal effects. Field experiments with wheat, soybeans, and rice confirmed that TiO₂ treatment significantly increased the crop yield. These findings suggest that TiO₂ is a promising nanomaterial for the simultaneous enhancement of plant growth and disease resistance.

Cadmium (Cd), a non-essential heavy metal, induces severe phytotoxicity through oxidative stress and cellular homeostasis disruption. Chronic Cd exposure inhibits plant growth via leaf chlorosis, stunted stem elongation, and impaired root architecture, while disrupting physiological functions through chlorophyll degradation, membrane peroxidation, and antioxidant system collapse. This review systematically investigates plant adaptive responses to Cd stress. It examines the processes of Cd uptake pathways, translocation dynamics, physiological toxicity, and molecular defense mechanisms. Key findings highlight two main protective strategies: avoidance mechanisms involving root secretion regulation, cellular compartmentalization, efflux transport, and the other through chelation, antioxidant systems, and phytohormonal regulation in tolerance mechanisms. A particular emphasis is placed on the coordinated actions between metal-chelating compounds (including PCs, MTs, and MTPs) and both enzymatic (SOD, CAT) and non-enzymatic antioxidants. These insights advance the theoretical framework for plant Cd resistance and inform innovative implications for developing effective remediation approaches.

To investigate the biological functions of Tiller Angle Control 2 (TAC2) in Salix psammophila. In this study, TAC2 was cloned from Salix psammophila, and an overexpression and subcellular localization expression vector for the SpsTAC2 gene was constructed. The SpsTAC2 gene was overexpressed in Arabidopsis and analyzed for phenotypic changes. The subcellular localization of SpsTAC2 was analyzed via Agrobacterium-mediated transient expression in onion (Allium cepa L.) epidermal cells. Phenotypic characterization of SpsTAC2 overexpressing Arabidopsis strains revealed that the branching angle of the transgenic strains was significantly greater than that of the wild type, and the anatomical structures of the stems and hypocotyls of the transgenic strains indicated that the vascular system of the transgenic strains developed more slowly than did that of the wild type. The subcellular localization of the SpsTAC2 gene revealed that the localization signals of the SpsTAC2 gene were mainly in the nucleus, and weak signals also appeared in the cell membrane, suggesting that the SpsTAC2 gene was mainly expressed mainly in the nucleus, with a small amount of expression in the cell membrane. This findings suggest that the SpsTAC2 gene influences the development of the branching angle of plants and xylem, and exerts its effects mainly in the nucleus and membrane. This study can help to characterize the regulatory effect of the TAC gene on the branching angle and explore its effect on the branching angle and vascular system development, and also help to explore the possible molecular regulatory mechanism, which can provide a theoretical basis for further elucidation of the mechanism of action of the IGT gene family.