AlphaFold-guided redesign of a plant pectin methylesterase inhibitor for broad-spectrum disease resistance

Plant cell walls are a critical site where plants and pathogens continuously struggle for physiological domi-nance.Here we show that dynamic remodeling of pectin methylesterification of plant cell walls is a compo-nent of the physiological and co-evolutionary struggles between hosts and pathogens.A pectin methyles-terase(PsPME1)secreted by Phytophthora sojae decreases the degree of pectin methylesterification,thus synergizing with an endo-polygalacturonase(PsPG1)to weaken plant cell walls.To counter PsPME1-mediated susceptibility,a plant-derived pectin methylesterase inhibitor protein,GmPMl1,protects pectin to maintain a high methylesterification status.GmPMl1 protects plant cell walls from enzymatic degrada-tion by inhibiting both soybean and P.sojae pectin methylesterases during infection.However,constitutive expression of GmPMl1 disrupted the trade-off between host growth and defense responses.We therefore used AlphaFold structure tools to design a modified form of GmPMI1(GmPMI1R)that specifically targets and inhibits pectin methylesterases secreted from pathogens but notfrom plants.Transient expression of GmPMi1R enhanced plant resistance to oomycete and fungal pathogens.In summary,our work highlights the biochemical modification of the cell wall as an important focal point in the physiological and co-evolutionary conflict between hosts and microbes,providing an important proof of concept that Al-driven structure-based tools can accelerate the development of new strategies for plant protection.

An introductory review on the common brown leafhopper(Orosius orientalis):A new soybean pest

Soybean pests are one of the major factors limiting yield improvement.With the expansion of area and changes in cropping patterns,a number of new pests have been identified in the main soybean production areas of China.The common brown leafhopper,Orosius orientalis,is a new pest associated with soybean stay-green virus that has been discovered on cultivated soybean crop in the Yellow-Huai-hai region of China in recent years.The polyphagous insect has a wide feeding range and infests a variety of important grain and cash crops.This paper presents the basic information,geographical distribution,hosts,damage characteristics,plant virus transmission,occurrence patterns,and prevention and control measures O.orientalis.This review also provides insights into integrated prevention and control of the genus Orosius as an insect vector.

Host niche, genotype, and field location shape the diversity and composition of the soybean microbiome

Plant-associated microbes represent a key determinant of plant fitness through acquiring nutrients,promoting growth,and resisting to abiotic and biotic stresses.However,an extensive characterization of the bacterial and fungal microbiomes present in different plant compartments of soybean in field conditions has remained elusive.In this study,we investigated the effects of four niches(roots,stems,leaves,and pods),four genotypes(Andou 203,Hedou 12,Sanning 16,and Zhonghuang 13),and three field locations(Jining,Suzhou,and Xuzhou)on the diversity and composition of bacterial and fungal communities in soybean using 16S and internal transcribed spacer rRNA amplicon sequencing,respectively.The soybean microbiome significantly differed across organs.Host genotypes explained more variation in stem bacterial community composition and leaf fungal community composition.Field location significantly affected the composition of bacterial communities in all compartments and the effects were stronger in the root and stem than in the leaf and pod,whereas field location explained more variation in stem and leaf fungal community composition than in the root and pod.The relative abundances of potential soybean fungal pathogens also differed among host organs and genotypes,reflecting the niches of these microbes in the host and probably their compatibility to the host genotypes.Systematic profiling of the microbiome composition and diversity will aid the development of plant protection technologies to benefit soybean health.

Genome sequencing reveals the evolution and pathogenic mechanisms of the wheat sharp eyespot pathogen Rhizoctonia cerealis

The necrotrophic fungus Rhizoctonia cerealis is the causal agent of devastating diseases of cereal crops including wheat(Triticum aestivum).We present a high-quality genome assembly of R.cerealis Rc207,a virulent strain causing wheat sharp eyespot.The assembly(56.36 Mb)is composed of 17.87%repeat sequences and 14,433 predicted protein-encoding genes.The Rc207 genome encodes a large and diverse set of genes involved in pathogenicity,especially rich in those encoding secreted proteins,carbohydrateactive enzymes(CAZymes),peptidases,nucleases,cytochrome P450,and secondary metabolismassociated enzymes.Most secretory protein-encoding genes,including CAZymes,peroxygenases,dehydrogenases,and cytochrome P450,were up-regulated during fungal infection of wheat.We identified 831 candidate secretory effectors and validated the functions of 10 up-regulated candidate effector proteins.Of them,nine were confirmed as necrotrophic pathogen’s effectors promoting fungal infection.Abundant potential mobile or plastic genomic regions rich in repeat sequences suggest their roles in fungal adaption and virulence-associated genomic evolution.This study provides valuable resources for further comparative and functional genomics on important fungal pathogens,and provides essential tools for development of effective disease control strategies.

Fusarium-produced vitamin B6 promotes the evasion of soybean resistance by Phytophthora sojae

Plants can be infected by multiple pathogens concurrently in natural systems. However,pathogen–pathogen interactions have rarely been studied. In addition to the oomycete Phytophthora sojae, fungi such as Fusarium spp. also cause soybean root rot. In a 3-year field investigation, we discovered that P. sojae and Fusarium spp. frequently coexisted in diseased soybean roots. Out of 336 P. sojae–soybean–Fusarium combinations,more than 80% aggravated disease. Different Fusarium species all enhanced P. sojae infection when co-inoculated on soybean. Treatment with Fusarium secreted non-proteinaceous metabolites had an effect equal to the direct pathogen coinoculation. By screening a Fusarium graminearum mutant library, we identified Fusarium promoting factor of Phytophthora sojae infection 1(Fpp1),encoding a zinc alcohol dehydrogenase. Fpp1 is functionally conserved in Fusarium and contributes to metabolite-mediated infection promotion, in which vitamin B6(VB6) produced by Fusarium is key. Transcriptional and functional analyses revealed that Fpp1 regulates two VB6 metabolism genes, and VB6 suppresses expression of soybean disease resistance-related genes. These results reveal that co-infection with Fusarium promotes loss of P. sojae resistance in soybean, information that will inform the sustainable use of diseaseresistant crop varieties and provide new strategies to control soybean root rot.

A new distinct geminivirus causes soybean stay-green disease

Dear Editor,Plant viruses make up almost half of the plant disease-causing pathogens,affecting crop yields and the global economy(Savary et al.,2019).Soybean(Glycine max)is one of the most valuable legume crops in the world,supplying 25%of the global edible oil and two-thirds of the global concentrated protein for livestock feeding.Recently,the outbreak of soybean stay-green syndrome with delayed leaf senescence(stay-green),flat pods,and increased number of abnormal seeds has swept the soybean production in the Huang-Huai-Hai region of China,resulting in huge yield losses(Xu et al.,2019).This disease has become an epidemic and prominent problem in soybean production and is still expanding its geography,including North America,posing a serious threat to soybean production(Harbach et al.,2016;Zhang et al.,2016;Li et al.,2019).However,the cause of soybean stay-green syndrome remains obscure.

Decoding the biochemical dialogue:metabolomic insights into soybean defense strategies against diverse pathogens

Soybean,a crucial global leguminous crop,confronts persistent threats from diverse pathogens,exerting a profound impact on global yields.While genetic dimensions of soybean-pathogen interactions have garnered attention,the intricate biochemical responses remain poorly elucidated.In this study,we applied targeted and untargeted liquid chromatography coupled to mass spectrometry(LC-MS)metabolite profiling to dissect the complex interplay between soybeans and five distinct pathogens.Our analysis uncovered 627 idMS/MS spectra,leading to the identification of four main modules,encompassing flavonoids,isoflavonoids,triterpenoids,and amino acids and peptides,alongside other compounds such as phenolics.Profound shifts were observed in both primary and secondary metabolism in response to pathogenic infections.Particularly notable were the bidirectional changes in total flavonoids across diverse pathogenic inoculations,while triterpenoids exhibited a general declining trend.Noteworthy among the highly inducible total flavonoids were known representative antipathogen compounds(glyceollin I),backbone forms of isoflavonoids(daidzein,genistein,glycitein,formononetin),and newly purified compounds in this study(prunin).Subsequently,we delved into the biological roles of these five compounds,validating their diverse functions against pathogens:prunin significantly inhibited the vegetative growth and virulence of Phytophthora sojae;genistein exhibited a pronounced inhibitory effect on the vegetative growth and virulence of Phomopsis longicolla;daidzein and formononetin displayed significant repressive effects on the virulence of P.longicolla.This study underscores the potent utility of metabolomic tools,providing in-depth insights into plant-pathogen interactions from a biochemical perspective.The findings not only contribute to plant pathology but also offer strategic pathways for bolstering plant resistance against diseases on a broader scale.

Microbe-derived non-necrotic glycoside hydrolase family 12 proteins act as immunogenic signatures triggering plant defenses

Plant pattern recognition receptors(PRRs)are sentinels at the cell surface sensing microbial invasion and activating innate immune responses.During infection,certain microbial apoplastic effectors can be recognized by plant PRRs,culminating in immune responses accompanied by cell death.However,the intricated relationships between the activation of immune responses and cell death are unclear.Here,we studied the glycoside hydrolase family12(GH12)protein,Ps109281,secreted by Phytophthora sojae into the plant apoplast during infection.Ps109281 exhibits xyloglucanase activity,and promotes P.sojae infection in a manner dependent on the enzyme activity.Ps109281 is recognized by the membranelocalized receptor-like protein RXEG1 and triggers immune responses in various plant species.Unlike other characterized GH12 members,Ps109281 fails to trigger cell death in plants.The loss of cell death induction activity is closely linked to a sequence polymorphism at the Nterminus.This sequence polymorphism does not affect the in planta interaction of Ps109281 with the recognition receptor RXEG1,indicating that cell death and immune response activation are determined using different regions of the GH12 proteins.Such GH12 protein also exists in other Phytophthora and fungal pathogens.Taken together,these results unravel the evolution of effector sequences underpinning different immune outputs.