Rice Blast Research Articles

Epigenetic modulation of fungal pathogens: a focus on Magnaporthe oryzae.

Epigenetics has emerged as a potent field of study for understanding the factors influencing the effectiveness of human disease treatments and for identifying alternations induced by pathogens in host plants. However, there has been a paucity of research on the epigenetic control of the proliferation and pathogenicity of fungal plant pathogens. Fungal plant pathogens such as Magnaporthe oryzae, a significant threat to global rice production, provide an important model for exploring how epigenetic mechanisms govern fungal proliferation and virulence. In M. oryzae, epigenetic alterations, such as DNA methylation, histone modification, and non-coding RNAs, regulate gene expression patterns that influence the pathogen's ability to infect its host. These modifications can enhance fungal adaptability, allowing the pathogen to survive in diverse environments and evade host immune responses. Our primary objective is to provide a comprehensive review of the existing epigenetic research on M. oryzae and shed light on how these changes influence the pathogen's lifecycle, its ability to invade host tissues, and the overall severity of the disease. We begin by examining the epigenetic alterations occurring in M. oryzae and their contributions to the virulence and proliferation of the fungus. To advance our understanding of epigenetic mechanisms in M. oryzae and similar plant diseases, we emphasize the need to address unanswered questions and explore future research directions. This information is crucial for developing new antifungal treatments that target epigenetic pathways, which could lead to improved disease management.

Active DNA Demethylation Mediated by OsGADD45a2 Regulates Growth, Development, and Blast (Magnaporthe oryzea) Resistance in Rice.

OsGADD45a1, a member of the growth arrest and DNA damage-inducible 45 (GADD45) family in rice, has a newly identified homologue, OsGADD45a2, which differs from OsGADD45a1 in only three amino acids. The role and function of the OsGADD45a2 in DNA demethylation are not well-understood and were investigated in this study. Osgadd45a2 mutants exhibited reduced height, shorter panicle length, fewer grains per panicle, and a lower seed setting rate compared with wild-type plants. Moreover, the results showed that OsGADD45a2 negatively regulates rice blast fungus resistance and exhibited high expression in various tissues. Using the 3000 Rice Genomes Project database, we identified four major haplotypes (each with over 100 cultivars) based on single-nucleotide polymorphisms in the coding sequence of OsGADD45a2. Among these, Hap4 was associated with a significantly greater plant height than Hap1-3, possibly due to a functional alteration of OsGADD45a2 linked to the SNP at position 2614993. In OsGADD45a2 overexpression lines, significant decreases in CG and CHG methylation levels were observed in protein-coding genes, leading to their upregulation. Overall, our findings indicate that OsGADD45a2 acts as a methylation regulator, mediating the expression of genes essential for plant growth and development and blast resistance.

Exploring the molecular mechanisms of rice blast resistance and advances in breeding for disease tolerance.

Rice blast, caused by the fungus Magnaporthe oryzae (syn. Pyricularia oryzae), is a major problem in rice cultivation and ranks among the most severe fungal diseases. Cloning and identifying resistance genes in rice, coupled with a comprehensive examination of the interaction between M. oryzae and rice, may provide insights into the mechanisms of rice disease resistance and facilitate the creation of new rice varieties with improved germplasm. These efforts are essential for protecting food security. This review examines the discovery of genes that confer resistance or susceptiblity to M. oryzae in rice over the last decade. It also discusses how knowledge of molecular mechanisms has been used in rice breeding and outlines key strategies for creating rice varieties resistant to this disease. The strategies discussed include gene pyramiding, molecular design breeding, editing susceptibility genes, and increasing expression of resistance genes through pathogen challenge. We address the prospects and challenges in breeding for rice blast resistance, emphasizing the need to fully exploit germplasm resources, employ cutting-edge methods to identify new resistance genes, and develop innovative breeding cultivars. Additionally, we underscore the importance of understanding the molecular basis of rice blast resistance and developing novel cultivars with broad-spectrum disease resistance.

Identification of significant SNPs and candidate loci for blast disease resistance via GWAS and population structure analysis in ARC panel of Oryza sativa

Identification of significant SNPs and candidate loci for blast disease resistance via GWAS and population structure analysis in ARC panel of Oryza sativa

Arabidopsis METHYLENETETRAHYDROFOLATE REDUCTASE 2 functions independently of PENETRATION 2 during primary immunity against rice blast.

Nonhost resistance (NHR) is the most durable and robust form of innate immunity, with a surge of interest in crop improvement. Of the NHR genes identified against rice blast, a devastating disease caused by Magnaporthe oryzae, Arabidopsis PEN2 is indispensable for pre-penetration resistance against M. oryzae, while a consortium of genes orchestrates post-penetration resistance via lesser-known mechanisms. We identified M. oryzae-susceptible mosA (mthfr2 pen2-3) from a randomly mutagenized Arabidopsis pen2-3 population using forward genetics. Analysis of T-DNA inserted mthfr2 lines and pen2-3 complemented mosA lines enunciated that MTHFR2-dependent resistance to M. oryzae is independent of PEN2. MTHFR2-defective plants exhibited higher ROS accumulation and expression of SA-dependent defense markers. MTHFR2-ligand docking revealed that A55V nonsynonymous substitution in mosA altered ligand binding efficiency. This further affected the metabolomic profile of mosA, effectively allowing in vitro germination and development of M. oryzae conidia. Moreover, the loss of function mutation in mthfr2 (involved in 1C metabolic pathway) potentiated mosA immunity against Pst DC3000. In conclusion, our findings assert MTHFR2 as a positive modulator of NHR against M. oryzae. This work documents another layer of conserved yet divergent metabolomic defense in Arabidopsis regulated by folate-mediated 1C metabolism that has the potential to revolutionize crop improvement.

Chinese Populations of Magnaporthe oryzae Serving as a Source of Human-Mediated Gene Flow to Asian Countries: A Population Genomic Analysis

Magnaporthe oryzae, a filamentous heterothallic ascomycete fungus that serves as the causative agent of rice blast disease, is globally distributed in rice-growing regions. Populations shaped by environmental factors and human intervention play important roles in the formation of genetic structure. In this study, population structures and spatiotemporal dynamics were investigated based on large-scale whole genomic sequences of rice-infecting M. oryzae around the world. By analyzing these genetic structures, we identified divergent clades that crossed geographic boundaries. While we observed associations between the isolates and their geographic origins, we also found that there were frequent migration events occurring across Asia in main rice cultivation regions. Within Asia, China was the migration origin, facilitating gene flows to Japan and South Korea. Since the 1970s, the genetic diversity of M. oryzae populations in China has also shown a steadily increasing trend, continuing through to the 2020s. Additionally, our analysis of the evolutionary history of Asian M. oryzae populations provided insights into the population expansion that has taken place in recent decades. Overall, our findings indicate that human-mediated gene flows played a pivotal role in shaping the genetic structure of M. oryzae.

Preparation of pH-Responsive Kas@ZnO Quantum Dots for Synergistic Control of Rice Blast and Enhanced Disease Resistance in Rice.

The construction of controlled-release formulations improves the sustained-release performance and utilization efficiency of pesticides, which are important aspects in plant protection and environmental chemistry. The current study employs kasugamycin (Kas), which is widely used to control Magnaporthe oryzae, conjugated with carboxyl-functionalized ZnO quantum dots via amide linkages to yield a pH-responsive pesticide delivery system (Kas@ZnO). Physicochemical characterizations indicated the successful preparation of the Kas@ZnO nanoparticles. In vitro drug release assessments indicated that Kas@ZnO exhibited a loading capacity of 21.05% and could effect the controlled release of Kas in an acidic environment, which is beneficial given the unique acidic microenvironment of M. oryzae. Bioactivity assays demonstrated that Kas@ZnO could simultaneously inhibit mycelial growth and spore germination. Additionally, bioactivity tests showed that the control efficacy of Kas@ZnO against rice blast reached 67.43% after 14 days of in vivo spray inoculation, which was higher than that obtained with Kas (55.50%), suggesting improved beneficial effects of Kas@ZnO application over a prolonged duration. Moreover, Kas@ZnO enhanced the activity of defense-related enzymes in rice and upregulated the expression of defense-related genes, such as OsPR2, OsPR3, OsPR5, OsWRKY45, OsLYP6, and OsNAC4. Ultimately, the biosafety assessments revealed that Kas@ZnO did not exert any harmful effects on rice and demonstrated slight toxicity toward zebrafish. These findings indicate that Kas@ZnO can function as a pH-sensitive pesticide delivery system, allowing for targeted release of the pesticide within plant tissues. This technology demonstrates significant potential for eco-friendly plant disease management.

Separation and purification of antimicrobial substances from Paenibacillus polymyxa KH-19 and analysis of its physicochemical characterization.

Soft rot is one of the top ten most dangerous plant pathogens in agricultural production, storage, and transport, and the use of microorganisms and their metabolites to control soft rot is a current research hotspot. In this study, we identified the antimicrobial substance in the metabolite of Paenibacillus polymyxa KH-19, and determined that the antimicrobial substance of this strain was an active protein. The protein was completely precipitated at 40-60% ammonium sulphate saturation and showed good inhibitory effects against seven pathogenic bacteria including Pectobacterium carotovorum BC2 and seven pathogenic fungi including Pyricularia oryzae. The MIC of the protein was 51.563µg/mL, temperature acid-base UV and light stability insensitive to protease, with high-temperature resistance. The antimicrobial protein was isolated and purified by DEAE-anion exchange column and Sephadex G-75 gel filtration chromatography, and the LC-MS/MS assay identified the protein as lysophosphatidyl esterase with a molecular weight of 25.255kDa. The purified antimicrobial protein increased the inhibitory effect against P. carotovorum BC2, with the diameter of the circle of inhibition being 26.50 ± 0.915mm. Bioinformatics analysis showed that the protein has the molecular formula of C1117H1732N316O338S5, encodes 224 amino acids, has an aliphatic index of 88.39, and belongs to the category of hydrophilic unstable proteins. The present study is the first report of an active protein with extreme thermoplastic and resistance to P. carotovorum BC2, which provides a reference for the preparation and application of the antimicrobial substances of P. polymyxa KH-19, as well as a theoretical basis for the study of the function of lysophosphodiesterase protein and its use as a microbial preparation.

Evaluating Alternative Fungicides for Effective Management of Rice Blast Disease: Inhibitory Effects on Pyricularia oryzae Cavara

Tricyclazole has been a successful solution for managing rice blast for over three decades. However, the continuous use of this fungicide has led to the development of resistance and the accumulation of tricyclazole residues within rice grains, prompting a ban on its usage in India. In response to this pressing issue, the present study aims to evaluate the efficacy of alternative fungicides in controlling the growth of Pyricularia oryzae, the causal agent of rice blast. The study employed a comprehensive approach, assessing the performance of various fungicides, including picoxystrobin, hexaconazole, isoprothiolane, kresoxim methyl, pyraclostrobin, tebuconazole, kitazin, and zineb, at varying dosage levels (100%, 75%, and 50% of the recommended dose). The findings of this investigation indicated that hexaconazole, isoprothiolane, kitazin, and zineb exhibited a 100% inhibition of P. oryzae growth across all tested doses. Pyraclostrobin also demonstrated a 100% inhibition at the highest dose, although its effectiveness decreased slightly at lower doses. In contrast, picoxystrobin and kresoxim methyl did not exhibit significant effectiveness in controlling the growth of the rice blast pathogen. These results provide valuable insights into the potential alternatives to tricyclazole for managing rice blast when used either alone or in combination at reduced doses.

Characterization of Endophytic Streptomyces rhizosphaericola Ahn75 and Its Potential for Biocontrol against Rice Blast.

Plant endophyte Streptomyces are excellent candidates as biocontrol agents against the rice blast fungus, Magnaporthe oryzae. In this study, a novel strain Ahn75 with antifungal activity was isolated from healthy rice stem and identified as Streptomyces rhizosphaericola by phenotypic characterization and phylogenetic analysis based on 16S rRNA, multilocus and genome sequences. Inhibition test using culture filtrate showed that Ahn75 could effectively suppress M. oryzae, with mycelia growth inhibition rate of 80.88% and spore germination inhibition rate of 78.26%. Genome sequence analysis of strain Ahn75 showed 40 gene clusters of secondary metabolites and several genes related to plant growth promotion were predicted in the genome of Ahn75. Several antimicrobial compounds including valinomycin, tetrabutylammonium, and benzalkonium chloride, were also detected in the antifungal fraction from Ahn75 culture filtrate by liquid chromatography and high resolution mass spectrometry. Meanwhile, strain Ahn75 demonstrates UV tolerance under UV irradiation for 60 min, pH tolerance between pH6 and pH9, and a high halotolerance in 7% (w/v) of NaCl. Greenhouse experiments indicated that Ahn75 is able to colonize rice stems, roots, and leaves, which help rice to reduce the rice leaf blast incidence by 59.76%. All these findings suggest that strain Ahn75 could be a potential biocontrol agent for rice blast.

Novel SDH Inhibitors as Antifungal Leads: From Azobenzene Derivatives to the 1,2,4-Oxadiazole Compounds.

Azo-incorporating was reported to be an effective strategy for increasing SDH inhibitory activity but for poor in vivo control effects. Herein, the azo-incorporated compounds were structurally optimized to retain a preferential conformation by replacing the azo bond with their bioisosteres. Interestingly, the 1,2,4-oxadiazole compound D2 displayed a broad fungicidal spectrum as well as fluxapyroxad. More excitedly, compound D2 showed excellent antifungal activities against rice sheath blight disease both in vitro (EC50 = 0.001 μg/mL) and in vivo (EC50 = 1.08 μg/mL, EC95 = 4.67 μg/mL). In addition, an extra π-π interaction was found between the 1,2,4-oxadiazole ring of compound D2 and the phenyl ring of residue D_Y586, which might interpret the enhanced potency of compound D2 against Rhizoctonia solani. Further structural optimizations of the 1,2,4-oxadiazole compounds gave several analogues that made a breakthrough in controlling rice blast disease. These 1,2,4-oxadiazole compounds, derived from azobenzene derivatives, could be antifungal leads especially against R. solani and Magnaporthe grisea, exemplifying an interesting mode of pesticide discovery and providing theoretical guidance for innovation of the SDHI fungicide.

The nucleolin MoNsr1 plays pleiotropic roles in the pathogenicity and stress adaptation in the rice blast fungus Magnaporthe oryzae.

The rice blast disease, caused by the fungus Magnaporthe oryzae, is a significant agricultural problem that adversely impacts rice production and food security. Understanding the precise molecular pathways involved in the interaction between the pathogen and its host is crucial for developing effective disease management strategies. This study examines the crucial function of the nucleolin MoNsr1 in regulating M. oryzae physiological functions. ΔMoNsr1 deletion mutants showed reduced fungal growth, asexual sporulation, and pathogenicity compared to the wild-type. Mutants exhibited impaired conidial germination and appressoria formation, reducing infection progression. Additionally, ΔMoNsr1 deletion mutant had less turgor pressure, confirming that MoNsr1 is essential for cell wall biogenesis and resistant to external stresses. Furthermore, ΔMoNsr1 deletion mutant showed enhanced sensitivity to oxidative stress, reactive oxygen species, and cold tolerance. Our results offer a thorough understanding of the function of MoNsr1 in the virulence and stress-resilient capability in M. oryzae. These findings provide insights into the novel targets and contribute to the emergence of innovative approaches for managing rice blast disease.

Phytochrome B promotes blast disease resistance and enhances yield in rice.

Phytochromes are red/far-red light receptors that regulate various aspects of plant growth, development and stress responses. The precise mechanism by which Phytochrome B (PhyB)-mediated light signaling influences plant defense and development remains unclear. In this study, we showed that PhyB enhances rice (Oryza sativa) blast disease resistance, tillering, and grain size compared to wild-type plants. Notably, PhyB interacted with and degraded grassy tiller 1 (GT1), a negative regulator of tiller development. Knockdown of GT1 in a phyB background partially rescued the diminished tillering of phyB. However, GT1 negatively regulates rice resistance to blast, suggesting that PhyB degradation of GT1 promotes tillering but not blast resistance. Previously, PhyB was found to interact with and degrade phytochrome-interacting factor 15 (PIL15), a key regulator of seed development that reduces rice resistance to blast and seed size. pil15 mutation in phyB mutants rescued phyB seed size and blast resistance, suggesting that PhyB might interact with and degrade PIL15 to negatively regulate blast resistance and seed size. PIL15 directly activated sugar will be eventually exported transporter 2a (SWEET2a). sweet2a mutants were less susceptible to blast disease compared to wild type. Collectively, these data demonstrate that PhyB promotes rice yield and blast resistance by inhibiting the transcription factors GT1 and PIL15 and downstream signaling.

Efficacy of Different Bio-agents, Botanicals, Fungicides and Nano-fungicides against Pyricularia oryzae

A study was conducted during the period 2021-2023 at, Department of Plant Pathology, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur and the field experiments at Student Instructional Farm, Chandra Shekhar Azad University of agriculture and Technology, during research period different bio-agent, botanicals, Azotrix (Azoxystrobin 16.7 % + Tricyclazole 33.3% SC) and nanofunficides are used and data were recorded regarding there efficacy in inhibition of mycelial growth of Pyricularia oryzae causing rice blast in Completely randomised design (CRD) under in-vitro condition by adopting principle of dual culture technique and food poision technique. All the selected treatments proved effective and reduce mycelial growth of pathogen, among bioagents T. viride (46.47%) were superior over T. harzianum (43.26 %) and Pseudomonas fluorescence (57.71 %) was better than Bacillus subtilis (48.54%), in botanicals bael leaf extract were found superior (86.32%) over neem leaf extract (74.43%), Fungicide (Azotrix @ 25, 50 and 100ppm) can reduce growth upto 85% over control and among nanofungicides Silver nanoparticles @10ppm was found best which can inhibit (61.87%) mycelial growth.

Exploring Distribution and Evolution of Pi-ta Haplotypes in Rice Landraces across Different Rice Cultivation Regions in Yunnan.

Background: Rice blast, caused by Magnaporthe oryzae, seriously damages the yield and quality of rice worldwide. Pi-ta is a durable resistance gene that combats M. oryzae carrying AVR-Pita1. However, the distribution of the Pi-ta gene in rice germplasms in Yunnan Province has been inadequately studied. Methods: We analyzed the potential molecular evolution pattern of Pi-ta alleles by examining the diversity in the coding sequence (CDS) among rice varieties. Results: The results revealed that 95% of 405 rice landraces collected from different ecological regions in Yunnan Province carry Pi-ta alleles. We identified 17 nucleotide variation sites in the CDS regions of the Pi-ta gene across 385 rice landraces. These variations led to the identification of 28 Pi-ta haplotypes, encoding 12 novel variants. Among these, 5 Pi-ta haplotypes (62 rice landraces) carried R alleles. The evolutionary cluster and network of the Pi-ta haplotypes suggested that the Pi-ta S alleles were the ancestral alleles, which could potentially evolve into R variants through base substitution. Conclusions: This study suggests that Pi-ta alleles are diverse in the rice landraces in Yunnan, and the Pi-ta sites resistant to blast evolved from the susceptible plants of the rice landraces. These results provide the basis for breeding resistant varieties.

Rice Blast Disease

The purpose of this document is to increase awareness of rice blast disease by describing its lifestyle, symptoms, and current disease mitigation practices. Given that the Everglades Agricultural Area (EAA) plays a vital role in rice cultivation, this publication is also intended for Florida rice growers to be used as a diagnostic field guide in the identification and management of rice blast disease. Written by Nalleli Garcia, Rachel Kalicharan, and Jessie Fernandez Garcia, and published by the UF/IFAS Department of Microbiology and Cell Science, September 2024.

Influence of cultivar selection on blast and brown spot diseases in rice: Molecular screening of blast resistance genes  

The prevalence of blast and brown spot diseases in rice is a substantial threat to national food security. This study investigated the distribution patterns of blast and brown spot, comparing their occurrence and distribution with respect to cultivar selection and conducting molecular screening for the identification of blast resistance genes. The research was conducted over five cultivating seasons from Yala 2017 to Yala 2019 in the Northern Province of Sri Lanka. Incidence percentages of the two diseases were calculated in 114 randomly selected fields across the five districts; Jaffna, Mullaitheevu, Kilinochchi, Mannar, and Vavuniya. Molecular markers were used to screen for nine major blast-resistant genes in 25 commonly cultivated rice cultivars. The results showed a significant shift in the disease over the period of study. While blast disease incidence declined after Maha 2017, brown spot incidence increased steadily from Yala 2017, peaking in Yala 2019. Interestingly, farmers’ cultivar preferences, often diverging from the Department of Agriculture recommendations, exhibited a strong correlation with disease occurrence. The cultivar Attakkari was identified as a highly susceptible cultivar, which had only three R genes and a major contributor to the progression of blast before Maha 2017. Despite higher brown spot incidence percentages observed in cultivars At362, Bw367, and Bg450, compared to Bg360, intensive post-Maha 2017 cultivation of Bg360 increased the average brown spot incidence to 43%. Cultivars grown after Maha 2017, with over five R genes, showed lower blast disease incidence, suggesting a genetic link to susceptibility. This lower incidence of blast was also observed in the disease evaluation test, where we used the same cultivars. Hence, this study highlights rice cultivar selection as a decisive factor influencing disease occurrence. Given Sri Lanka’s robust germplasm for blast-resistant genes, strategic cultivar selection has the potential for effective disease management.

Efficient gene editing with an Arg-tRNA promoter-driven CRISPR/Cas9 in the rice blast fungus Pyricularia oryzae

CRISPR/Cas9 technology has been widely adopted for genome editing in a wide range of organisms, including many fungi. Pyricularia oryzae is a filamentous fungal pathogen that causes the devastating rice blast disease. However, an efficient and cost-effective CRISPR/Cas9 system for the rice blast fungus has yet to be established. Here, we report an 84-bp arginyl (Arg)-tRNA promoter-driven CRISPR/Cas9 system, which enables efficient and cost-effective gene editing in P. oryzae. Preliminary screening of three tRNAs from the 179 predicted tRNAs in P. oryzae showed that two Arg-tRNA CRISPR/Cas9 cassettes reproducibly generated MoB56 disruption efficiently. Further, five genes located on distinct chromosomes, including two previously uncharacterized genes, were randomly picked up to test the efficiency of the Mo_tRNAArg24-gRNA-Cas9 cassette. Ppg1 is a gene essential to the pathogenicity and important for mycelial growth and conidiation of P. oryzae, which is located at chromosome 2 and exhibited a relatively low gene replacement rate (< 1/500) by the traditional gene replacement approach. By using the Mo_tRNAArg24-gRNA-Cas9 cassette, Ppg1 gene disruption rate was increased up to 75.9%. In addition, Bip2, an uncharacterized genes located close to the centromere of chromosome 4, was disrupted at 66.7%. For all the five tested genes, our Mo_tRNAArg24-gRNA-Cas9 cassette showed high gene disruption efficiency in P. oryzae, ranging from 66.7% to 100%. Importantly, it rarely induces Cas9 toxicity to P. oryzae. The Mo_tRNAArg24-gRNA-Cas9 cassette described in this study can be adopted as an alternative for functional genomics study in P. oryzae.

In Vitro Inhibition of Rhizoctonia oryzae-sativae Using Bacterial Strains as a Sustainable Alternative for Controlling Sheath Blight in Rice

In Vitro Inhibition of Rhizoctonia oryzae-sativae Using Bacterial Strains as a Sustainable Alternative for Controlling Sheath Blight in Rice

The roles of Magnaporthe oryzae avirulence effectors involved in blast resistance/susceptibility.

Phytopathogens represent an ongoing threat to crop production and a significant impediment to global food security. During the infection process, these pathogens spatiotemporally deploy a large array of effectors to sabotage host defense machinery and/or manipulate cellular pathways, thereby facilitating colonization and infection. However, besides their pivotal roles in pathogenesis, certain effectors, known as avirulence (AVR) effectors, can be directly or indirectly perceived by plant resistance (R) proteins, leading to race-specific resistance. An in-depth understanding of the intricate AVR-R interactions is instrumental for genetic improvement of crops and safeguarding them from diseases. Magnaporthe oryzae (M. oryzae), the causative agent of rice blast disease, is an exceptionally virulent and devastating fungal pathogen that induces blast disease on over 50 monocot plant species, including economically important crops. Rice-M. oryzae pathosystem serves as a prime model for functional dissection of AVR effectors and their interactions with R proteins and other target proteins in rice due to its scientific advantages and economic importance. Significant progress has been made in elucidating the potential roles of AVR effectors in the interaction between rice and M. oryzae over the past two decades. This review comprehensively discusses recent advancements in the field of M. oryzae AVR effectors, with a specific focus on their multifaceted roles through interactions with corresponding R/target proteins in rice during infection. Furthermore, we deliberated on the emerging strategies for engineering R proteins by leveraging the structural insights gained from M. oryzae AVR effectors.