Molecular Plant最新文献

Cyclic nucleotide-gated ion channels (CNGCs) are key components in pattern-triggered immunity (PTI) signaling. Tight control of CNGC homeostasis is crucial for maintaining a balance between plant growth and immunity. Nevertheless, the mechanisms for fine-tuning CNGC homeostasis remain largely unknown. Here, we report that Arabidopsis thaliana CNGC3 is a functional calcium channel to mediate pattern-induced Ca²⁺ influx, PTI, and resistance to Sclerotinia sclerotiorum. We identified a CNGC interactor, Skp1-interacting protein 31 (SKIP31). In the absence of a pathogen, SKIP31 ubiquitinates CNGC3 at Lys8 and Lys33 of the K-X-V-R motif for degradation to repress plant immunity. When a pathogen attacks, activated receptor-like cytoplasmic kinase (RLCK) BOTRYTIS-INDUCED KINASE1 (BIK1) phosphorylates SKIP31 to inhibit its ubiquitin ligase activity and interaction with the CNGC3 N-terminal region, thereby suppressing CNGC3 protein degradation to promote immunity. Phosphorylation within the F box of SKIP31 at Ser88 and Ser93 and at the C-terminal Ser261 prevents its interaction with Skp1 and CNGC3, respectively. These phosphorylation sites are conserved in SKIP31 of different plant species, and SKIP31 interacts with all examined CNGCs, suggesting a pivotal role of SKIP31 phosphorylation in regulating CNGC stability and plant immunity. Moreover, biochemical assays revealed that BIK1 directly phosphorylates the CNGC3 cytoplasmic C-terminal region at four Ser residues to enhance its Ca²⁺ channel activity, demonstrating dual roles of BIK1 in both promoting CNGC channel activity and stabilizing the channel protein. Collectively, our work unveils an SCF ubiquitin ligase-RLCK control system that fine-tunes the homeostasis of CNGCs for orchestrating plant immunity.

Plants can cope with stresses via the "cry-for-help" strategy, but how aboveground insect herbivores induce alterations in the rhizosphere microbiota through eliciting this plant-driven response remains unexplored. In this study, we exposed cabbage plants to aboveground insect herbivory for five sequential planting rounds in the same soil. New cabbage plants, growing in the soils conditioned for five rounds, showed a significant increase in resistance to aboveground insect herbivory. Analyses of microbial communities in the rhizosphere of cabbage plants revealed that this effect was attributed to the accumulation of Pseudomonas in herbivore-conditioned soils. Rhizophere metabolic profiling further identified that some amino acids were present at higher concentrations in the rhizosphere of cabbage plants suffering from insect herbivory. Beneficial Pseudomonas species could be enriched by applying these amino acids. Notably, cabbage plants exhibited the highest resistance to insect herbivory following the application of a synbiotic, a combination of amino acids (prebiotics) and Pseudomonas spp. (probiotics). Moreover, we showed that Pseudomonas activates the jasmonate signaling pathway in the plant, which occurred in salicylic acid-deficient, but not in jasmonic acid-deficient, Arabidopsis thaliana mutants and led to the induction of glucosinolate-based defenses against insect herbivory. Collectively, this work reveals a belowground cry-for-help response in plants induced by aboveground herbivory, enabling the development of a novel synbiotic for plant health maintenance.

Strigolactones (SLs) are not only phytohormones that influence multiple aspects of plant growth and development but also signaling molecules for interactions between plants and certain fungi or bacteria. In plants, the SL receptor is an α/β-hydrolase (ABH) encoded by the DWARF14 (D14)/KARRIKIN INSENSITIVE2 (KAI2) gene family, which is known to be derived from proteobacterial RsbQ through horizontal gene transfer (HGT). In the phytopathogenic fungus Cryphonectria parasitica, another ABH named CpD14 was found to possess SL binding and hydrolytic activities and mediate SL responses, exhibiting potential SL perception functions. Here, we demonstrate that CpD14 and its homologs in Leotiomyceta fungi were derived from Actinobacteria through an independent HGT event, forming a distinct CpD14-like (CDL) family across fungi and bacteria. X-ray crystallography and structural analyses reveal that actinobacterial and fungal CDL proteins share a conserved core "α/β fold" domain with D14/KAI2/RsbQ but possess a unique lid domain. Biochemical assays show that both actinobacterial CDL and proteobacterial RsbQ can recognize and hydrolyze SLs, suggesting that they are pre-adapted for SL responses and potential perception. Both plant D14/KAI2 and fungal CDL proteins retained these functional activities, whereas they evolved distinct ligand specificities for SL structural variants. Collectively, this work reveals that independent HGT events from two bacterial groups provided plants and their interacting fungi with pre-adapted ABH proteins, which were deployed for SL perception or responses.

Plants have developed a multi-layered immune system to cope with pathogens. The receptors on the plasma membrane are controlled by endocytosis to modulate immune signaling, but the regulatory mechanisms of endocytosis in this process remain largely unclear. Here, we uncover that reversible S-acylation of BONZAI1 (BON1), a conserved copine-family protein that regulates development-immunity balance in Arabidopsis, contributes to the accurate control of endocytosis. BON1 is targeted by S-acylation, a type of protein lipidation, for its localization on the plasma membrane and its function in development and immunity. Furthermore, the S-acylation status of BON1 affects its association with the light-chain clathrin subunit CLC3 and regulates endocytosis. Specifically, PAT14 facilitates the S-acylation of BON1, while ABAPT11 mediates its de-S-acylation. Physiological levels of reversible S-acylation of BON1 are essential for endocytosis and the internalization of immune receptors. Interestingly, salicylic acid enhances ABAPT11-dependent de-S-acylation of BON1 to amplify immune signaling. Collectively, our study reveals that reversible S-acylation of BON1 precisely regulates immune receptor internalization for balancing plant development and immunity, providing potential targets that may be used to improve crop yields and disease resistance.

This study introduces multi-dimensional environment (MDE) zoning to enhance maize resilience and improve stagnant yields in China amid climate change. Utilizing comprehensive environmental and yield data, MDE zoning accurately identifies areas for targeted, climate-adaptive breeding. The tool provides a flexible framework for updates using annual variety testing and daily environmental data, optimizing maize production and resource allocation.

Reactive oxygen species play a crucial role in various stages of the legume-rhizobia symbiosis, from initial nodulation signaling to nodule senescence. However, how rhizobial redox-related proteins regulate symbiotic nodulation in legumes remains largely unknown. By combining transcriptomics, proteomics, and biochemical and molecular genetics, we investigated the role of the Sinorhizobium fredii Q8 enzyme 3-mercaptopyruvate sulfurtransferase (3MST). Although 3MST was not the primary enzyme responsible for hydrogen sulfide (H₂S) production under our conditions, its absence significantly impaired symbiotic nodule development, redox homeostasis, infection capacity, and nitrogen-fixation efficiency in soybean. We identified a host plasma membrane-localized NADPH oxidase, respiratory burst oxidase homolog B (RbohB), as a key regulator of immune activation during nodule development. Notably, 3MST was secreted during nodulation and localized in the nucleoid and cytoplasmic membrane, where it interacts with and persulfidates RbohB at Cys791, thereby suppressing the NADPH oxidase activity of RbohB. We observed that 3MST-mediated persulfidation of RbohB maintains symbiotic redox balance and promotes nodule development. Genetic analyses in soybean, including RbohB overexpression, RNA interference, and site-directed mutagenesis at Cys791, further supported this observation, linking the 3MST-RbohB interaction to effective rhizobial colonization and improved plant growth. Taken together, these findings uncover a rhizobia-initiated symbiotic regulatory mechanism by which a rhizobial sulfurtransferase modulates soybean RbohB via persulfidation to limit NADPH oxidase activity and promote nodulation.

Plant architecture is a critical agronomic trait directly affecting planting density and crop yield. Phosphate (Pi) starvation in rice (Oryza sativa) leads to a significant reduction in tiller number and a more upright leaf angle. Insensitivity to brassinosteroid (BR) signaling can lead to similar phenotypes. However, the molecular mechanisms underlying how Pi affects plant architecture through brassinosteroid signaling remain obscure. In this study, we demonstrate that the Pi starvation-induced E3 ligase OsPUB77 regulates rice shoot architecture by affecting leaf angle and tiller number. We further revealed that the Pi-signaling-related transcription factor RLI1a releases its repression of the expression of OsPUB77 under Pi deficiency. Subsequently, the accumulated OsPUB77 influences shoot architecture by ubiquitinating OsBZR3 to inhibit BR signaling. Furthermore, we found that natural variation in two single-nucleotide polymorphisms within the OsPUB77 U-box domain coding OsPUB77^R530 results in higher ubiquitin transfer activity than OsPUB77^I530 due to a stronger interaction with E2. Introducing the OsPUB77pro::OsPUB77^R530I transgene into the ospub77-1 background confirmed that OsPUB77^R530 results in more upright leaves. Collectively, our work identifies an RLI1a-OsPUB77-OsBZR3 module that mediates the crosstalk between Pi and BR signaling to shape shoot architecture in response to Pi starvation in rice.