Molecular plant pathology最新文献

MicroRNAs (miRNAs) are pivotal regulators of plant immunity. While our prior work implicated zma-miR169s in maize defence against Bipolaris maydis, its upstream regulation and downstream signalling mechanisms remained elusive. Here, we decipher a complete signalling pathway that confers resistance to B. maydis. We show that the transcription factor ZmWRKY92 directly binds to the promoter of zma-miR169s to suppress its transcription. Consistent with its role as a positive regulator, loss of ZmWRKY92 function increased maize susceptibility to the pathogen. We further delineate downstream of this pathway, demonstrating that ZmNF-YA13, a nuclear-localised target of zma-miR169s induced upon infection, is a positive defence regulator. Overexpression of ZmNF-YA13 enhanced resistance, whereas knockout mutants were more susceptible. Integrated multi-omics analysis further revealed that ZmNF-YA13 activates the flavonoid biosynthesis pathway, promoting the accumulation of antimicrobial compounds like gallocatechin, quercetin and chalcone. Collectively, our work establishes the ZmWRKY92-miR169s-ZmNF-YA13-flavonoid module as a key signalling pathway in maize antifungal immunity, providing novel targets for maize disease resistance improvement.

Arthrinium phaeospermum is the primary pathogen responsible for shoot blight disease in Bambusa pervariabilis × Dendrocalamopsis grandis. Previous research identified ApCtf1β, a key gene involved in pathogenicity encoding a cutinase transcription factor involved in pathogenicity, as essential for infecting hybrid bamboo. However, the interacting target proteins and functions of ApCtf1β within the fungus remain unclear, limiting the comprehensive understanding of A. phaeospermum's pathogenic pathways. Therefore, this study employed yeast two-hybrid, luciferase protein complementation, and GST pull-down assays to detect and confirm ApCtf1β-interacting proteins BDPH1 and BDEUL12. Further bioinformatics analyses of these proteins were conducted. Using Agrobacterium-mediated fungal genetic transformation, we generated BDPH1 and BDEUL12 overexpression transformants, gene-silenced transformants, as well as Apctf1β-BDPH1 and Apctf1β-BDEUL12 co-expression transformants. Functional studies of these interacting proteins were performed at different developmental stages, examining gene expression, hyphal growth rate, spore production, chemical susceptibility, pathogenicity and ubiquitination function. The results indicated that BDPH1 and BDEUL12 are closely associated with the virulence of A. phaeospermum, with the BDEUL12 gene exerting a more potent effect on virulence. This study provides a foundation for further elucidating the molecular mechanisms underlying the pathogenicity of A. phaeospermum.

Sugarcane mosaic virus (SCMV) causes substantial yield losses worldwide, yet the molecular basis underlying resistance and susceptibility in sugarcane remains incompletely understood. Here, we performed time-resolved transcriptome profiling of two contrasting sugarcane genotypes, the SCMV-susceptible cultivar Badila and its resistant somatic mutant FG1, across five infection stages. Absolute quantification revealed rapid viral RNA replication in Badila, whereas FG1 showed early suppression followed by SCMV clearance. Comparative transcriptomic analyses showed that FG1 mounted a rapid and sustained defence-associated transcriptional response, whereas Badila displayed delayed, predominantly repressive gene expression changes. Weighted gene co-expression network analysis identified gene modules strongly correlated with viral RNA levels and highlighted the small heat shock protein gene ScHSP17.5 as a central hub associated with susceptibility. Protein-protein interaction assays demonstrated that ScHSP17.5 and ScHSP17.9A specifically interact with the SCMV movement protein P3N-PIPO, but not with P3 or the coat protein. Functional assays in Nicotiana benthamiana further showed that overexpression of either ScHSP enhanced SCMV RNA replication, with co-expression producing a synergistic effect. Together, these results support a model in which SCMV exploits host small heat shock proteins via P3N-PIPO to promote viral accumulation, whereas early redox- and signalling-associated responses restrict infection in resistant sugarcane. This study provides mechanistic insight into SCMV-host interactions and identifies candidate targets for resistance breeding.

Begomoviruses transmitted by whiteflies cause severe crop losses worldwide. Individual strains or isolates have a narrower host range, but collectively begomoviruses infect a wide range of plants. Begomovirus genomes undergo frequent recombination and mutations that confer a selective advantage in interactions with specific host factors facilitating host range adaptation, resulting in the rapid emergence of new strains with adapted host range. In this study, we examined the processes by which the begomoviruses can acquire and lose hosts by exchanging fragments of the viral genomes between a variant of tomato leaf curl New Delhi virus only infecting cucumber (ToLCNDV-C), tomato leaf curl Karnataka virus only infecting tomato (ToLCKV-T), and a ToLCNDV strain infecting both tomato and cucumber (ToLCNDV-T&C). We mapped the region responsible for tomato host loss to a 63 nucleotide (nt) region in the C-terminal of the transcriptional activator/replication enhancer protein (TrAP/REn) regions of ToLCNDV. We tested known host proteins reported to interact with this region using the yeast two-hybrid approach and found divergence in interactions with host proteins PCNA and AGO1. Finally, we found that the TrAP/REn region of DNA-A in conjunction with DNA-B can confer ToLCKV-T the ability to weakly infect its non-host, cucumber, and ToLCNDV-C to infect its non-host, tomato. Our studies reveal that multiple complex intra-virus interactions between viral proteins and virus-host interactions govern infectivity, virus accumulation and symptom severity.

Mating-type (MAT) loci are traditionally considered vestigial remnants in asexual fungi, yet their widespread retention suggests additional, yet unrecognised functions. Here we show that in the asexual plant pathogen Fusarium oxysporum f.sp. lycopersici the two MAT loci function as master regulators of developmental processes through autocrine pheromone signalling. MAT1-1 and MAT1-2 exhibit opposing regulatory roles in density-dependent conidial germination, creating a bistable switch for population-level behavioural coordination. MAT1-1 promotes vegetative hyphal fusion and multicellular aggregation, whereas MAT1-2 inhibits these processes. These opposing effects are mediated in part by enhanced expression of the protease Bar1 in MAT1-2 isolates, which specifically cleaves α-pheromone thereby modulating signalling responses. Unexpectedly, MAT1-1 enhances virulence of F. oxysporum on tomato plants in a background-dependent manner, whereas MAT1-2 exhibits only a slight influence on pathogenicity. Together, our findings establish that MAT loci have undergone evolutionary repurposing to control essential developmental processes through autocrine communication networks, revealing novel targets for sustainable disease management approaches.

The WRKY transcription factor is a key regulatory protein involved in defence hormone signalling and plays a pivotal role in plant hormone-mediated disease resistance. However, the specific mechanism by which WRKY transcription factors regulate the jasmonic acid (JA) pathway to confer resistance against Verticillium wilt in cotton remains poorly understood. In this study, we demonstrated that GbWRKY11 expression in Gossypium barbadense was induced by both Verticillium dahliae and methyl jasmonate (MeJA), and its encoded protein functioned as a nuclear transcription activator. Functional analyses revealed that GbWRKY11 enhances Verticillium wilt resistance by modulating JA pathway-related gene expression in both cotton and Arabidopsis. Exogenous MeJA application restored resistance in GbWRKY11-silenced plants, further supporting its role in JA-mediated immunity. Mechanistically, GbWRKY11 directly binds to the W-box motif in the promoter of GbLOX5, a key JA biosynthesis gene, and activates its transcription. Silencing GbLOX5 compromised cotton resistance to Verticillium wilt, confirming the importance of JA synthesis in this defence response. Our findings elucidate the molecular mechanism by which GbWRKY11 mediates immune responses against Verticillium wilt, providing novel insights into the genetic resources associated with disease resistance in G. barbadense.

Sclerotinia sclerotiorum is a destructive pathogen with a broad host range, long-term soil survival, and is difficult to control. Silencing virulence-related genes is a strategy for controlling Sclerotinia disease. In this study, we identified and characterised Sspdhx, which encodes pyruvate dehydrogenase complex component X in S. sclerotiorum. Sspdhx deletion exhibited significant impairments in growth, sclerotia development, infection cushion formation, and virulence, indicating that Sspdhx plays important biological functions in S. sclerotiorum. Sspdhx deletion also resulted in reducing acetyl-CoA and ATP levels, and increased sensitivity to multiple environmental stresses. Exogenous supplementation with acetyl-L-carnitine partially restored the virulence of the ΔSspdhx mutants. Transcriptomic analyses revealed that deletion of Sspdhx disrupts central carbon metabolic homeostasis, leading to broad transcriptional reprogramming that affects genes involved in vegetative growth, stress adaptation, and virulence-associated processes. Application of exogenous Sspdhx-targeting dsRNA and host-induced gene silencing in plants effectively silenced Sspdhx and attenuated the virulence of S. sclerotiorum. These findings potentially establish Sspdhx as a promising target for RNA-based control strategies against Sclerotinia disease.

Enterobacter species occur across diverse habitats and are best known for causing opportunistic and nosocomial infections in humans. The taxonomy of this genus is complex, with many species reassigned to and from this genus. Their interaction with plants is multifaceted. Strains of certain species cause opportunistic plant diseases.

Host range: Enterobacter species affect a wide range of plant hosts.

Disease symptoms: They cause a range of symptoms including leaf spots and blight, wilt and root diseases, decay and soft rot and cankers.

Plant-beneficial traits: Some Enterobacter species include strains that are plant growth promoters and occur either in the rhizosphere or as endophytes. Additionally, some strains can protect their hosts from pathogen attack and are regarded as promising biological control agents. Some strains also have potential for the bioremediation of various compounds.

Genomic features: Information on the pathogenicity and virulence mechanisms of plant-pathogenic Enterobacter species is limited. Comparison of diverse genomic features revealed no overall differences between plant-pathogenic and plant-beneficial strains.

Conclusion: While often reported as a plant pathogen, there is currently no evidence that Enterobacter is the primary cause of any of the reported diseases. In many cases, they would rather act opportunistically. This remains a significant concern, as a wide range of hosts are affected, and problems may intensify due to global warming. It is crucial to investigate these strains for plant pathogenicity and evaluate the risks to human health.

The oomycete Phytophthora capsici causes Phytophthora blight, a major constraint on global pepper production. Our previous observations indicated that pretreating plants with thiamethoxam (TMX) and imidacloprid (IMI) could reduce the incidence of pepper blight, but the underlying mechanisms remained unclear. Here, we investigated how TMX and IMI induced resistance in pepper (Capsicum frutescens) against P. capsici. Both in vitro and in vivo assays demonstrated that TMX and IMI suppressed disease, not by directly impairing pathogen virulence but by inducing systemic resistance in susceptible (Cusheng L09) and resistant (Cusheng 356) pepper cultivars. Split-plant systemic resistance assays showed that TMX/IMI-primed plants developed smaller lesions in both treated and untreated leaves following P. capsici infection. Foliar application of TMX and IMI effectively alleviated disease severity, with IMI showing superior efficacy in attenuating reactive oxygen species (ROS) accumulation, and TMX/IMI priming concomitantly altering the activities of ROS-scavenging enzymes under pathogen challenge. Reverse transcription-quantitative PCR analysis revealed time-dependent changes in defence gene expression, and whole-genome transcriptome profiling highlighted temporal reprogramming of pathogenesis-related genes. Further functional validation identified CaNEN4 as a susceptibility factor. Collectively, our findings reveal that IMI/TMX primes pepper plants with systemic resistance by modulating ROS homeostasis, defence gene expression, and susceptibility gene function, offering novel insights into chemical-induced plant immunity and genetic targets for durable blight resistance in crops.

Food security remains a pressing global challenge, particularly for staple crops like rice. The traditional Yunnan landrace rice variety Mowanggu (MWG) exhibits broad-spectrum and durable resistance to Magnaporthe oryzae, the causal agent of destructive rice blast disease, making it a valuable germplasm resource for breeding. However, the molecular mechanisms underlying this resistance remain unclear due to the lack of a high-quality genome. Here, we present a chromosome-scale draft genome assembly of MWG, combining Nanopore long-read and Illumina short-read sequencing. Through comparative genomic analyses, we identified structural variations, gene family expansions and divergence events. We identified nine RLK genes within the Pi49 resistance locus, among which overexpression of OSAmwg_038136 enhanced the expression of pathogenesis-related genes and increased resistance to rice blast. OSAmwg_038136 was shown to interact with OsDIP1, a member of the R3H protein family, which positively regulates blast resistance. Our findings provide critical insights into the molecular basis of MWG durable blast resistance and offer a foundation for engineering broad-spectrum disease resistance in rice.