DGS1 improves rice disease resistance by elevating pathogenassociated molecular pattern-triggered immunity

Rice yield and disease resistance are two crucial factors in determining the suitability of a gene for agricultural breeding.Decreased grain size1(DGS1),encoding an RING-type E3 ligase,has been found to have a positive effect on rice yield by regulating rice grain number and 1000-grain weight.However,the role of DGS1 in rice blast resistance is still unknown.In this study,we report that DGS1 enhances disease resistance by improving PTI responses,including stronger ROS burst and MAPK activation,and also increased expression of defense-related genes.Furthermore,DGS1 works in conjunction with ubiquitin conjugating enzyme OsUBC45 as an E2-E3 pair to facilitate the ubiquitin-dependent degradation of OsGSK3 and OsPIP2;1,thereby influencing rice yield and immunity,respectively.Therefore,the DGS1-OsUBC45 module has the potential in facilitating rice agricultural breeding.

Species of Botryosphaeriaceae involved in grapevine dieback in China

Botryosphaeria dieback is a serious disease problem for table and grape wine production worldwide.The disease however,has been less well-studied in China.In this study,we surveyed Botryosphaeria dieback in 72 vineyards of 20 grape-growing regions in China and found that Botryosphaeria dieback occurs in 18 out of 20 provinces.Morphological and multi-gene phylogenetic analyses confirmed that Botryosphaeria dothidea,Diplodia seriata,Lasiodiplodia theobromae and Neofusicoccum parvum are associated with different grapevine dieback symptoms.This study also revealed considerable differences in the geographical distribution of Botryosphaeriaceae species in China with Lasiodiplodia theobromae and Neofusicoccum parvum occurring only in subtropical monsoon climate regions,Diplodia seriata occurring only in temperate monsoon climate regions,and Botryosphaeria dothidea occurring in both temperate and subtropical monsoon climate regions.Analysis of 26 isolates showed that there is little genetic variation within species.Koch’s postulates were satisfied for all species,and pathogenicity testing showed that among the 25 major cultivars growing in China,none was resistant to the four taxa.The current paper represents the first detailed report on Botryosphaeria dieback of grapevines in China.

Diverse species of Colletotrichum associated with grapevine anthracnose in China

Grapevine anthracnose is an important disease,responsible for mild to severe yield losses in grape production,and is also an important post harvest disease.The disease was studied in vineyards in six provinces in China,with 34 isolates obtained from diseased grapes.Multi-gene(ACT,ITS,GAPDH,TUB2 and CHS)analysis coupled with morphology showed that Colletotrichum aenigma,C.hebeiense sp.nov.and C.viniferum were associated with grapevine anthracnose in China.Colletotrichum aenigma is reported for the first time as associated with grapevine anthracnose.Colletotrichum hebeiense is a new species introduced here.Pathogenicity testing showed that all species can infect grapes,causing anthracnose however,virulence of species and isolates showed great variation.Phylogenetic analysis showed that C.viniferum is a cryptic species and its taxonomy needs to be resolved in the future.

Structure-guided analysis of Arabidopsis JASMONATE-INDUCED OXYGENASE(JOX)2 reveals key residues for recognition of jasmonic acid substrate by plant JOXs

The jasmonic acid(JA)signaling pathway is used by plants to control wound responses.The persistent accumulation of JA inhibits plant growth,and the hydroxylation of JA to 12-hydroxy-JA by JASMONATE-INDUCED OXYGENASEs(JOXs,also named jasmonic acid oxidases)is therefore vital for plant growth,while structural details of JA recognition by JOXs are unknown.Here,we present the 2.65Åresolution X-ray crystal structure of Arabidopsis JOX2 in complex with its substrate JA and its co-substrates 2-oxoglutarate and Fe(Ⅱ).JOX2 contains a distorted double-stranded p helix(DSBH)core flanked by a helices and loops.JA is bound in the narrow substrate pocket by hydrogen bonds with the arginine triad R225,R350,and R354 and by hydrophobic interactions mainly with the phenylalanine triad F157,F317,and F346.The most critical residues for JA binding are F157 and R225,both from the DSBH core,which interact with the cyclopentane ring of JA.The spatial distribution of critical residues for JA binding and the shape of the substrate-binding pocket together define the substrate selectivity of the JOXs.Sequence alignment shows that these critical residues are conserved among JOXs from higher plants.Collectively,our study provides insights into the mechanism by which higher plants hydroxylate the hormone JA.

Comparative Secretome Analysis of Magnaporthe oryzae Identified Proteins Involved in Virulence and Cell Wall Integrity

Plant fungal pathogens secrete numerous proteins into the apoplast at the plant–fungus contact sites to facilitate colonization.However,only a few secretory proteins were functionally characterized in Magnaporthe oryzae,the fungal pathogen causing rice blast disease worldwide.Asparagine-linked glycosylation 3(Alg3)is an a-1,3-mannosyltransferase functioning in the Nglycan synthesis of N-glycosylated secretory proteins.Fungal pathogenicity and cell wall integrity are impaired inΔalg3 mutants,but the secreted proteins affected inΔalg3 mutants are largely unknown.In this study,we compared the secretomes of the wild-type strain and theΔalg3 mutant and identified 51 proteins that require Alg3 for proper secretion.These proteins were predicted to be involved in metabolic processes,interspecies interactions,cell wall organization,and response to chemicals.Nine proteins were selected for further validation.We found that these proteins were localized at the apoplastic region surrounding the fungal infection hyphae.Moreover,the Nglycosylation of these proteins was significantly changed in theΔalg3 mutant,leading to the decreased protein secretion and abnormal protein localization.Furthermore,we tested the biological functions of two genes,INV1(encoding invertase 1,a secreted invertase)and AMCase(encoding acid mammalian chinitase,a secreted chitinase).The fungal virulence was significantly reduced,and the cell wall integrity was altered in theΔinv1 andΔamcase mutant strains.Moreover,the N-glycosylation was essential for the function and secretion of AMCase.Taken together,our study provides new insight into the role of N-glycosylated secretory proteins in fungal virulence and cell wall integrity.

Natural variations of maize ZmLecRK1 determine its interaction with ZmBAK1 and resistance patterns to multiple pathogens

Maize(Zea mays)is one of the most important crops in the world,but its yield and quality are seriously affected by diverse diseases.Identifying broad-spectrum resistance genes is crucial for developing effective strategies to control the disease in maize.In a genome-wide study in maize,we identified a G-type lectin receptor kinase ZmLecRK1,as a new resistance protein against Pythium aphanidermatum,one of the causal pathogens of stalk rot in maize.Genetic analysis showed that the specific ZmLecRK1 allele can confer resistance to multiple pathogens in maize.The cell death and disease resistance phenotype mediated by the resistant variant of ZmLecRK1 requires the co-receptor ZmBAK1.A naturally occurring A404S variant in the extracellular domain of ZmLecRK1 determines the ZmLecRK1-ZmBAK1 interaction and the formation of ZmLecRK1-related protein complexes.Interestingly,the ZmLecRK1 susceptible variant was found to possess the amino acid S404 that is present in the ancestral variants of ZmLecRK1 and conserved among the majority of grass species,while the resistance variant of ZmLecRK1 with A404 is only present in a few maize inbred lines.Substitution of S by A at position 404 in ZmLecRK1-like proteins of sorghum and rice greatly enhances their ability to induce cell death.Further transcriptomic analysis reveals that ZmLecRK1 likely regulates gene expression related to the pathways in cell wall organization or biogenesis in response to pathogen infection.Taken together,these results suggest that the ZmLecRK1 resistance variant enhances its binding affinity to the co-receptor ZmBAK1,thereby enhancing the formation of active complexes for defense in maize.Our work highlights the biotechnological potential for generating disease-resistant crops by precisely modulating the activity of ZmLecRK1 and its homologs through targeted base editing.