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Disease outbreaks are shaped by the 'disease triangle,' comprising a virulent pathogen, a susceptible plant, and appropriate environmental conditions. Recent advances have shed light on the intricate environment–plant–pathogen interactions. Rice resistance is manipulated by cytoplasmic and apoplastic effectors secreted by Magnaporthe oryzae. Environmental factors play a significant role in both blast disease epidemics and the regulation of host (or rice) resistance. Strategies such as protein engineering, genome editing, and host-induced gene silencing have been employed effectively to engineer blast-resistant rice plants. Rice blast is a highly destructive crop disease that requires the interplay of three essential factors: the virulent blast fungus, the susceptible rice plant, and favorable environmental conditions. Although previous studies have focused mainly on the pathogen and rice, recent research has shed light on the molecular mechanisms by which the blast fungus and environmental conditions regulate host resistance and contribute to blast disease outbreaks. This review summarizes significant achievements in understanding the sophisticated modulation of blast resistance by Magnaporthe oryzae effectors and the dual regulatory mechanisms by which environmental conditions influence rice resistance and virulence of the blast fungus. Furthermore, it emphasizes potential strategies for developing blast-resistant rice varieties to effectively control blast disease. [ABSTRACT FROM AUTHOR]

Rice blast disease is the most devastating disease constraining crop productivity. Vertical resistance to blast disease is widely studied despite its instability. Clusters of genes or QTLs conferring blast resistance that offer durable horizontal resistance are important in resistance breeding. In this study, we aimed to refine the reported QTLs and identify stable meta-QTLs (MQTLs) associated with rice blast resistance. A total of 435 QTLs were used to project 71 MQTLs across all the rice chromosomes. As many as 199 putative rice blast resistance genes were identified within 53 MQTL regions. The genes included 48 characterized resistance gene analogs and related proteins, such as NBS–LRR type, LRR receptor-like kinase, NB-ARC domain, pathogenesis-related TF/ERF domain, elicitor-induced defense and proteins involved in defense signaling. MQTL regions with clusters of RGA were also identified. Fifteen highly significant MQTLs included 29 candidate genes and genes characterized for blast resistance, such as Piz, Nbs-Pi9, pi55-1, pi55-2, Pi3/Pi5-1, Pi3/Pi5-2, Pikh, Pi54, Pik/Pikm/Pikp, Pb1 and Pb2. Furthermore, the candidate genes (42) were associated with differential expression (in silico) in compatible and incompatible reactions upon disease infection. Moreover, nearly half of the genes within the MQTL regions were orthologous to those in O. sativa indica, Z. mays and A. thaliana, which confirmed their significance. The peak markers within three significant MQTLs differentiated blast-resistant and susceptible lines and serve as potential surrogates for the selection of blast-resistant lines. These MQTLs are potential candidates for durable and broad-spectrum rice blast resistance and could be utilized in blast resistance breeding. [ABSTRACT FROM AUTHOR]

Magnaporthe oryzae is a heterotrophic plant pathogenic fungus that developed the capability to colonies of living plant cells, A lot of genes play key roles in biological function, especially during the invasion process and biotrophic growth. but the mechanisms through which they establish bio-trophic growth by modifying gene expression are still unclear, we conducted an integrated analysis involving PRC2 genes which includes this description focusing on SUZ 12, EZH2 and EED1 proteins, revealing its crucial effect in the development and infection processes of the rice blast fungus, Magnaporthe oryzae. Deletion of SUZ 12, EZH2 and EED1 in M. oryzae resulted in a modest reduction in vegetative growth and a significant decrease in conidiation. Notably, the SUZ 12, EZH2 and EED1 mutants exhibited a marked reduction in virulence towards host plants. Observation of the infection process indicated that the mutants were halted in invasive growth, leading to the accumulation of substantial host reactive oxygen species (ROS). Additionally, the SUZ 12, EZH2 and EED1 mutants displayed sensitivity to cell wall-disturbing agents, These results suggest that the PRC2 complex plays an important role in biotrophic growth, thereby facilitating invasive growth in M. oryzae. [ABSTRACT FROM AUTHOR]

Rice blast disease, caused by the fungus Magnaporthe oryzae, poses a severe threat to rice production, particularly in Asia where rice is a staple food. Concerns over fungicide resistance and environmental impact have sparked interest in exploring natural fungicides as potential alternatives. This study aimed to identify highly potent natural fungicides against M. oryzae to combat rice blast disease, using advanced molecular dynamics techniques. Four key proteins (CATALASE PEROXIDASES 2, HYBRID PKS-NRPS SYNTHETASE TAS1, MANGANESE LIPOXYGENASE, and PRE-MRNA-SPLICING FACTOR CEF1) involved in M. oryzae's infection process were identified. A list of 30 plant metabolites with documented antifungal properties was compiled for evaluation as potential fungicides. Molecular docking studies revealed that 2-Coumaroylquinic acid, Myricetin, Rosmarinic Acid, and Quercetin exhibited superior binding affinities compared to reference fungicides (Azoxystrobin and Tricyclazole). High throughput molecular dynamics simulations were performed, analyzing parameters like RMSD, RMSF, Rg, SASA, hydrogen bonds, contact analysis, Gibbs free energy, and cluster analysis. The results revealed stable interactions between the selected metabolites and the target proteins, involving important hydrogen bonds and contacts. The SwissADME server analysis indicated that the metabolites possess fungicide properties, making them effective and safe fungicides with low toxicity to the environment and living beings. Additionally, bioactivity assays confirmed their biological activity as nuclear receptor ligands and enzyme inhibitors. Overall, this study offers valuable insights into potential natural fungicides for combating rice blast disease, with 2-Coumaroylquinic acid, Myricetin, Rosmarinic Acid, and Quercetin standing out as promising and environmentally friendly alternatives to conventional fungicides. These findings have significant implications for developing crop protection strategies and enhancing global food security, particularly in rice-dependent regions. [ABSTRACT FROM AUTHOR]

Nanotechnology-enabled pesticide delivery systems have been widely studied and show great prospects in modern agriculture. Nanodelivery systems not only achieve the controlled release of agrochemicals but also possess many unique characteristics. This study presents the development of a pH-responsive pesticide nanoformulation utilizing hollow mesoporous silica nanoparticles (HMSNs) as a nanocarrier. The nanocarrier was loaded with the photosensitive pesticide prochloraz (Pro) and then combined with ZnO quantum dots (ZnO QDs) through electrostatic interactions. ZnO QDs serve as both the pH-responsive gatekeeper and the enhancer of the pesticide. The results demonstrate that the prepared nanopesticide exhibits high loading efficiency (24.96%) for Pro. Compared with Pro technical, the degradation rate of Pro loaded in HMSNs@Pro@ZnO QDs was reduced by 26.4% after 24 h ultraviolet (UV) exposure, indicating clearly improved photostability. In a weak acidic environment (pH 5.0), the accumulated release of the nanopesticide after 48 h was 2.67-fold higher than that in a neutral environment. This indicates the excellent pH-responsive characteristic of the nanopesticide. The tracking experiments revealed that HMSNs can be absorbed by rice leaves and subsequently transported to other tissues, indicating their potential for effective systemic distribution and targeted delivery. Furthermore, the bioactivity assays confirmed the fungicidal efficacy of the nanopesticide against rice blast disease. Therefore, the constructed nanopesticide holds great prospect in nanoenabled agriculture, offering a novel strategy to enhance pesticide utilization. [ABSTRACT FROM AUTHOR]

Abstract Rice blast disease is the most devastating disease constraining crop productivity. Vertical resistance to blast disease is widely studied despite its instability. Clusters of genes or QTLs conferring blast resistance that offer durable horizontal resistance are important in resistance breeding. In this study, we aimed to refine the reported QTLs and identify stable meta-QTLs (MQTLs) associated with rice blast resistance. A total of 435 QTLs were used to project 71 MQTLs across all the rice chromosomes. As many as 199 putative rice blast resistance genes were identified within 53 MQTL regions. The genes included 48 characterized resistance gene analogs and related proteins, such as NBS–LRR type, LRR receptor-like kinase, NB-ARC domain, pathogenesis-related TF/ERF domain, elicitor-induced defense and proteins involved in defense signaling. MQTL regions with clusters of RGA were also identified. Fifteen highly significant MQTLs included 29 candidate genes and genes characterized for blast resistance, such as Piz, Nbs-Pi9, pi55-1, pi55-2, Pi3/Pi5-1, Pi3/Pi5-2, Pikh, Pi54, Pik/Pikm/Pikp, Pb1 and Pb2. Furthermore, the candidate genes (42) were associated with differential expression (in silico) in compatible and incompatible reactions upon disease infection. Moreover, nearly half of the genes within the MQTL regions were orthologous to those in O. sativa indica, Z. mays and A. thaliana, which confirmed their significance. The peak markers within three significant MQTLs differentiated blast-resistant and susceptible lines and serve as potential surrogates for the selection of blast-resistant lines. These MQTLs are potential candidates for durable and broad-spectrum rice blast resistance and could be utilized in blast resistance breeding.

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.

Rice cultivation in Madurai district, Tamil Nadu, spans distinct cropping seasons: Kar (May – Jun), Semi-dry (Jul – Aug), Samba/ Late Samba (Aug – Sep), and Navarai (Dec – Jan), each with unique weather conditions and rice varieties. This study explores the correlation between weather parameters temperature, rainfall, humidity, sunshine hours, and wind speed and rice blast disease severity from 2021 to 2023. Using multiple linear regression with ordinary least squares (OLS), the analysis achieves high predictive accuracy (R² = 0.98). Results show that the maximum temperatures correlated negatively with disease severity (r = -0.869 to -0.892), while rainfall (r = 0.768 to 0.804) and wind speed (r = 0.766 to 0.938) correlated positively during the semi-dry season. Relative humidity exhibits varying impacts across seasons. These findings underscore the importance of tailored disease management strategies, such as targeted fungicidal applications during warmer seasons and optimized water management in others. By elucidating these dynamics, the study enhances understanding of weather-disease interactions, providing actionable insights to optimize disease management and enhance crop resilience in Madurai district.

Blast disease causes significant damage to millets (pearl millet, finger millet and foxtail millet) and rice in India. This study investigates strains of Pyricularia, the causal agent of blast disease, in rice and millets in India in terms of their diversity, host preferences and phylogeny. One hundred and thirty‐six Pyricularia isolates causing rice and millet blast were collected from 46 locations in India. They displayed morphological diversity irrespective of host or location. All Pyricularia isolates were separated into two major clusters by a multilocus sequence‐based phylogenetic tree, which also demonstrated that most isolates are grouped according to their host associations. In contrast, a few finger millet isolates were found to be grouped with foxtail millet isolates. We explored how Pyricularia isolates behaved when exposed to rice and millets. Finger millet isolates were shown to be pathogenic on a wide variety of millets, whereas rice isolates were only found to infect rice and wheat. The majority of the blast isolates of millets were shown to be pathogenic on common weed species of the millet ecosystem, such as Echinochloa crusgalli, Eleusina indica and Erogrotis gagantica. Our findings emphasize the importance of pathogen surveillance in both cultivated crops and weed hosts, as well as the possible risk of blast fungus infection in Indian millets due to host expansion. Blast disease control programmes in India will be greatly enhanced by the knowledge gained in this study on the diversity and host association of Pyricularia strains. [ABSTRACT FROM AUTHOR]

Rice cultivation in Madurai district, Tamil Nadu, spans distinct cropping seasons: Kar (May -- Jun), Semi-dry (Jul - Aug), Samba/ Late Samba (Aug - Sep), and Navarai (Dec - Jan), each with unique weather conditions and rice varieties. This study explores the correlation between weather parameters temperature, rainfall, humidity, sunshine hours, and wind speed and rice blast disease severity from 2021 to 2023. Using multiple linear regression with ordinary least squares (OLS), the analysis achieves high predictive accuracy (R² = 0.98). Results show that the maximum temperatures correlated negatively with disease severity (r = -0.869 to -0.892), while rainfall (r = 0.768 to 0.804) and wind speed (r = 0.766 to 0.938) correlated positively during the semi-dry season. Relative humidity exhibits varying impacts across seasons. These findings underscore the importance of tailored disease management strategies, such as targeted fungicidal applications during warmer seasons and optimized water management in others. By elucidating these dynamics, the study enhances understanding of weather-disease interactions, providing actionable insights to optimize disease management and enhance crop resilience in Madurai district. [ABSTRACT FROM AUTHOR]

The rice blast disease caused by Pyricularia oryzae Cavara is among the most severe plant diseases in the world. The utilization of natural antagonists, such as fungal endophytes, can be a good method to control the spread of this disease. In the present study, 68 fungal isolates were obtained from 160 rice samples collected in Guilan province fields, Iran. Morphological and molecular characteristics were used for the identification of these fungi. According to the results, the fungal isolates were Alternaria citri (Penz.) Mussat, Alternaria infectoria Simmons, Aspergillus fumigatus Fresen, Fusarium verticillioides (Sacc.) Nirenberg, Trichoderma harzianum Rifai, Trichoderma virens (Mill., Giddens & Foster) Arx, Trichoderma viride Pers., Ulocladium consortiale (Thum) Simmons, and Pyricularia oryzae . Eight isolates that did not cause any plant disease were selected for biocontrol studies in vitro . The dual culture, culture filtrate, slide culture, and volatile metabolites methods were used in search of natural endophytic antagonists of Pyricularia oryzae . It was found that T. harzianum, T. virens, T. viride, A. fumigatus , and A. citri isolates caused the highest percentage of mycelial growth inhibition of P. oryzae in vitro . In the greenhouse experiments, all of the studied isolates reduced the P. oryzae disease rating, with T. harzianum isolate being the most effective antagonist (27.36% reduction in the disease rating), followed by T. virens, T. viride , and A. fumigatus (20.75%, 17.92%, and 16.98%, respectively). Furthermore, in greenhouse conditions, these antagonistic fungi increased the height, fresh weight, and dry weight of plants. The results of this research showed that there are various fungi in the natural flora of rice plants that possess potential biological properties against rice blast disease that can be implemented into practice.

Rice is a vital component in the diets of many people worldwide, supplying necessary calories for subsistence. Nevertheless, the yield of this crucial agricultural crop is consistently hindered by a range of biotic stresses. Out of these, rice blast, claused mainly by the fungus Magnaporthe oryzae, poses a significant menace to worldwide rice cultivation as well as yield in recent years. The consequences are particularly crucial given the current climate change challenges. In recent decades, substantial progress has been achieved in the development of efficient ways to manage rice blast disease. These procedures entail using a variety of rice genetic resources to find, map, clone, and functionally validate individual resistance (R) genes and quantitative trait loci (QTLs) that provide long-lasting resistance to rice blast disease. Moreover, the replication and practical confirmation of homologous avirulence (Avr) genes in various M. oryzae strains have been crucial in comprehending the fundamental molecular mechanisms of host–pathogen interactions. This article offers a thorough examination of the cloning and functional verification of different R genes and QTLs linked to resistance against rice blast disease. The complex interplay between R–Avr pairings, which contributes to the development of resistance against rice blast throughout a wide range, is thoroughly explained. Finally, this study explores the most recent progress in next-generation sequencing (NGS) and genome editing technologies (GETs), examining their potential uses in improving the treatment of rice blast disease. [ABSTRACT FROM AUTHOR]

Rice blast disease, caused by the fungal pathogen Magnaporthe oryzae, is a major threat to rice production worldwide. This study investigates the role of long non-coding RNAs (lncRNAs) in rice's response to this destructive disease, with a focus on their impacts on disease resistance and yield traits. Three specific lncRNAs coded by M. oryzae infection-responsive lncRNAs (MOIRAs), MOIRA1, MOIRA2, and MOIRA3, were identified as key regulators of rice's response to M. oryzae infection. Strikingly, when MOIRA1 and MOIRA2 were overexpressed, they exhibited a dual function: they increased rice's susceptibility to blast fungus, indicating a negative role in disease resistance, while simultaneously enhancing tiller numbers and single-plant yield, with no adverse effects on other yield-related traits. This unexpected improvement in productivity suggests the possibility of overcoming the traditional trade-off between disease resistance and crop yield. These findings provide a novel perspective on crop enhancement, offering a promising solution to global food security challenges by developing rice varieties that effectively balance disease resistance and increased productivity. [ABSTRACT FROM AUTHOR]

Abstract Rice blast is a serious threat to the safe production of grain crops such as rice and wheat. Sporulation, appressorium formation, and invasive growth of Magnaporthe oryzae are the key stages of the development and spread of rice blast epidemics. M. oryzae is a hemibiotrophic fungus that undergoes changes in available carbon sources during the infection cycle. Lipid is a major storage for M. oryzae spores and a major carbon source used in glycerol synthesis and turgor pressure generation in appressoria. The formation of a dense cell wall melanin layer is necessary for an appressorium to produce turgor and to be pathogenic. The plant cell wall is an important carbon source during the infection stage of M. oryzae. Transcription factors regulate gene expression in fungi and are key intermediates between the reception of external environmental signals and the control of development and pathogenicity in M. oryzae. The disease cycle of M. oryzae is controlled by some key transcription factors, such as sporulation by Cos1 and Hox2, appressorium formation by Sfl1, Hox7, and Vrf1, invasive growth by Mst12 and Mig1, and resistance to host basal immunity by Ap1 and Atf1. This review focuses on describing the key transcription factors of M. oryzae that regulate sporulation, appressorium formation, invasive growth, lipid metabolism, carbohydrate metabolism, melanin synthesis, oxidative response, and host basal immunity, as well as the working mechanism of the transcription factors.

This paper aims to extend the spore dispersal model to the Healthy-Latent-Infectious-Removed (HLIR) epidemic model for assessing the severity of rice blast disease. The model was solved by the Finite Difference Method (FDM). The results of the model were compared to data from the Prachinburi Rice Research Center (PRRC) on the severity of rice blast disease. Because of a small error, the comparison results showed good agreement between the PRRC data and the simulation by looking at the value of Willmott's index of agreement (d). The first bed d was 0.7166, while the second bed d was 0.6421, indicating the model's performance. Furthermore, the optimal parameter, the fraction of spores deposited on the crop, was determined to be 0.173 and 0.016 for beds 1 and 2, respectively. The model can simulate and analyze rice blast outbreaks for educational purposes in future preparedness planning.

To control blast disease in the rice field under natural conditions, three antagonistic isolates of rhizospheric P. fluorescens were formulated in talc, kaolinite, PVP, and vegetable oil using an RCBD with three replications. At various phases of the rice plants' growth, all of the products markedly accelerated plant growth and yield-contributing characteristics. Pf-8, compounded in talc (5 %) and vegetable oil (2 %) among the three isolates of P. fluorescens, significantly elevated vegetative and yield parameters with higher (2.11 and 2.08) benefit-cost ratios, respectively. At 90 days after transplanting (DAT), T11 (5 % Pf-8 Talc) and T13 (2 % Pf-8 Vegetable oil) showed a significant reduction in blast incidence (76.81 %, 75.45 %) and severity (71.57 %, 69.82 %), with the largest populations of P. fluorescens (9.60 × 1010 and 9.51 × 1010) in the rhizosphere. Moreover, a significantly increased level of phenol and hydrogen peroxide (H2O2) was found in Pseudomonas-treated leaves (Pf-8) at 30, 60, and 90 DAT indicating a strong relationship with rice blast disease reduction. Further, blast incidence and severity showed a negative correlation with vegetative parameters, yield parameters, phenol, and H2O2. Thus, it may be claimed that using formulated P. fluorescens (Pf-8) to manage rice blast in the field could be an alternate strategy to using chemicals.

This study evaluated the effects of Bacillus amyloliquefaciens D203 encapsulated in alginate-bentonite coating enriched with titanium nanoparticles on rice germination and Magnaporthe oryzae infection. Seed coating was achieved using the ionic gelation/extrusion method with modifications. The study investigated various concentrations of strain D203 on biomass and bacterial release from the beads, along with its influence on detached leaves. Results showed that treatment with a strain D203 cell suspension (2 × 107 CFU/ml) significantly enhanced root and shoot lengths, despite a slightly lower germination rate (90%) compared to the control. Treatment with a concentration of 1 × 107 proved to be optimum for growth because it maintained germination at 100% and boosted biomass growth of shoot and root by 49.57% and 16.44%, respectively. Colonization by strain D203, explored through seed coating and subsequent resuspension from roots and media, peaked in roots, indicating preferential root zone inhabitation. In vitro studies demonstrated strain D203’s efficacy against M. oryzae at 21 and 40 days, with the 1 × 107 CFU/ml spray significantly reducing disease symptoms. Strain D203 exhibited a preventive effect, especially in early growth stages. The encapsulated form of strain D203 had a control effect comparable to 40% Hexaconazole but less effective than 75% Tricyclazole. Uncoated and encapsulated B. amyloliquefaciens treatments significantly improved sterile rice plant growth over 21 days, with the encapsulated bead treatment surpassing both controls and free cell treatments by days 14 and 21, despite slower initial growth. Encapsulation presents a promising alternative, potentially matching the effectiveness of chemical fungicides, emphasizing the importance of environmentally friendly alternatives in sustainable disease management strategies.

Molecular docking was done to investigate the interactions between five differentially expressed rice WRKY proteins when challenged with the rice blast disease caused by Magnaporthe oryzae and drought stresses applied either individually or overlapped, with the promoter region of two blast resistance genes (Pi2 and Pi54). Molecular docking was performed using the HDOCK server. Initially, the homology models for each of the five rice WRKY proteins were prepared using I-TASSER server, and then the secondary structure as well as the DNA-binding pockets were predicted using PSIPRED and BindUP servers, respectively. The molecular docking study revealed a differential binding pattern of the rice WRKYs with the two blast resistance genes. The WRKY proteins (OsWRKY88 and OsWRKY102), whose transcript levels decrease when drought and blast stresses are overlapped, interact with the two resistance genes mostly involving the residues of the zinc finger structure. On the other hand, the WRKY proteins (OsWRKY53-1 and OsWRKY113), whose transcript levels did not reduce significantly when challenged by drought and blast overlapped condition compared to individual treatment of blast, interact mostly involving the residues of the conserved WRKYGQK heptapeptide sequence. Interestingly, the protein OsWRKY74 whose transcript levels are unaffected in both individual and overlapped stresses, interacts with both the blast resistance genes involving few residues of both WRKYGQK heptapeptide and the zinc finger structure. The findings thus indicate that the interaction of OsWRKY proteins involving the conserved WRKYGQK heptapeptide sequence with the blast resistance genes Pi2 and Pi54 is important to mitigate the blast challenge in rice even during overlapping challenges of drought. [ABSTRACT FROM AUTHOR]

von Willebrand factor A (vWA) genes are well characterized in humans except for few BONZAI genes, but the vWA genes are least explored in plants. Considering the novelty and vital role of vWA genes, this study aimed at characterization of vWA superfamily in rice. Rice genome was found to have 40 vWA genes distributed across all the 12 chromosomes, and 20 of the 40 vWA genes were unique while the remaining shared large fragment similarities with each other, indicating gene duplication. In addition to vWA domain, vWA proteins possess other different motifs or domains, such as ubiquitin interacting motif in protein degradation pathway, and RING finger in protein-protein interaction. Expression analysis of vWA genes in available expression data suggested that they probably function in biotic and abiotic stress responses including hormonal response and signaling. The frequency of transposon elements in the entire 3K rice germplasm was negligible except for 9 vWA genes, indicating the importance of these genes in rice. Structural and functional diversities showed that the vWA genes in a blast-resistant rice variety Tetep had huge variations compared to blast-susceptible rice varieties HP2216 and Nipponbare. qRT-PCR analysis of vWA genes in Magnaporthe oryzae infected rice tissues indicated OsvWA9, OsvWA36, OsvWA37 and OsvWA18 as the optimal candidate genes for disease resistance. This is the first attempt to characterize vWA gene family in plant species.

Rice yield can be significantly impacted by rice blast disease. In this investigation, an endophytic strain of Bacillus siamensis that exhibited a potent inhibitory effect on the growth of rice blast was isolated from healthy cauliflower leaves. 16S rDNA gene sequence analysis showed that it belongs to the genus Bacillus siamensis. Using the rice OsActin gene as an internal control, we analyzed the expression levels of genes related to the defense response of rice. Analysis showed that the expression levels of genes related to the defense response in rice were significantly upregulated 48 h after treatment. In addition, peroxidase (POD) activity gradually increased after treatment with B-612 fermentation solution and peaked 48 h after inoculation. These findings clearly demonstrated that the 1-butanol crude extract of B-612 retarded and inhibited conidial germination as well as the development of appressorium. The results of field experiments showed that treatment with B-612 fermentation solution and B-612 bacterial solution significantly reduced the severity of the disease before the seedling stage of Lijiangxintuan (LTH) was infected with rice blast. Future studies will focus on exploring whether Bacillus siamensis B-612 produces new lipopeptides and will apply proteomic and transcriptomic approaches to investigate the signaling pathways involved in its antimicrobial effects. [ABSTRACT FROM AUTHOR]

Rice blast disease, caused by the fungus Magnaporthe oryzae, poses a severe threat to rice production, particularly in Asia where rice is a staple food. Concerns over fungicide resistance and environmental impact have sparked interest in exploring natural fungicides as potential alternatives. This study aimed to identify highly potent natural fungicides against M. oryzae to combat rice blast disease, using advanced molecular dynamics techniques. Four key proteins (CATALASE PEROXIDASES 2, HYBRID PKS-NRPS SYNTHETASE TAS1, MANGANESE LIPOXYGENASE, and PRE-MRNA-SPLICING FACTOR CEF1) involved in M. oryzae's infection process were identified. A list of 30 plant metabolites with documented antifungal properties was compiled for evaluation as potential fungicides. Molecular docking studies revealed that 2-Coumaroylquinic acid, Myricetin, Rosmarinic Acid, and Quercetin exhibited superior binding affinities compared to reference fungicides (Azoxystrobin and Tricyclazole). High throughput molecular dynamics simulations were performed, analyzing parameters like RMSD, RMSF, Rg, SASA, hydrogen bonds, contact analysis, Gibbs free energy, and cluster analysis. The results revealed stable interactions between the selected metabolites and the target proteins, involving important hydrogen bonds and contacts. The SwissADME server analysis indicated that the metabolites possess fungicide properties, making them effective and safe fungicides with low toxicity to the environment and living beings. Additionally, bioactivity assays confirmed their biological activity as nuclear receptor ligands and enzyme inhibitors. Overall, this study offers valuable insights into potential natural fungicides for combating rice blast disease, with 2-Coumaroylquinic acid, Myricetin, Rosmarinic Acid, and Quercetin standing out as promising and environmentally friendly alternatives to conventional fungicides. These findings have significant implications for developing crop protection strategies and enhancing global food security, particularly in rice-dependent regions.

Rice is one of the staple foods for the majority of the global population that depends directly or indirectly on it. The yield of this important crop is constantly challenged by various biotic stresses. Rice blast, caused by Magnaporthe oryzae (M. oryzae), is a devastating rice disease causing severe yield losses annually and threatening rice production globally. The development of a resistant variety is one of the most effective and economical approaches to control rice blast. Researchers in the past few decades have witnessed the characterization of several qualitative resistance (R) and quantitative resistance (qR) genes to blast disease as well as several avirulence (Avr) genes from the pathogen. These provide great help for either breeders to develop a resistant variety or pathologists to monitor the dynamics of pathogenic isolates, and ultimately to control the disease. Here, we summarize the current status of the isolation of R, qR and Avr genes in the rice–M. oryzae interaction system, and review the progresses and problems of these genes utilized in practice for reducing rice blast disease. Research perspectives towards better managing blast disease by developing a broad-spectrum and durable blast resistance variety and new fungicides are also discussed. [ABSTRACT FROM AUTHOR]

Rice is one of the important food sources in human nutrition. Rice blast disease caused Pyricularia oryzae is the most destructive disease which is seen in rice growing. The aim of this study was to investigate the effect of different spraying and planting methods on disease severity and yield in rice fields in the Mediterranean Region. Field trials were conducted onto rice fields which were grown Edirne variety in the Tabaklar village, Yüregir, Adana province and Sökün village, Silifke, Mersin province in 2011 and 2012, respectively. As a result of this study, the use of treated seeds and seedlings reduced the severity of the disease. The lowest disease severity was found as 6.1% and 9.3% where it was used by years. However, the disease severity was also recorded as the lowest value by 6.6% and 4.6%, respectively through foliar spraying in the plot where the seedlings were performed from treated seeds by years. No impact on different spraying and planting methods on the yield was found.

Aims To characterize the functional role of extracellular polysaccharides and lipopolysaccharide (LPS) extracted from endophytic Pseudomonas putida BP25 (PpBP25) against rice blast. Methods and Results We profiled the transcriptome of endobacterized rice seedlings using RNA-seq. Fluorescence imaging of interaction between Magnaporthe :: gfp and P. putida :: mCherry was performed on rice phylloplane using confocal laser scanning microscopy (CLSM). Microbial polysaccharides, exopolysaccharide (EPS), and LPS extracted from PpBP25 were characterized using Fourier-transform infrared-spectroscopic analysis (FTIR). Biochemical assays and gene expression analysis were conducted on EPS- and LPS-treated rice seedlings. A detached-leaf assay was designed to test the blasticidal-effect of bacterial-endophyte, EPS, and LPS on rice phylloplane. PpBP25 elicited defense in rice with a consequently altered seedling phenotype. Rice cultivar, Pusa Basmati-1, colonized by PpBP25 showed an altered transcriptome profile displaying a total of 110-downregulated and 68-upregulated genes (P  < 0.005) representing growth/development and defense pathways, respectively. CLSM of PpBP25 bacterized phylloplane showed reduced conidial-germination and mycelial-biomass of Magnaporthe oryzae. To decipher the elicitor role of polysaccharides, we purified and characterized EPS and LPS using FTIR. Rice treated with the EPS and LPS showed root-growth inhibition the phenotype of MAMP-triggered immunity. While the EPS showed blast suppressive activity at 1–20 mg mL−1 (79.80%–86.87% reduction over control), the LPS exhibited 78.0%–79.8% reduction at 20–200 μg mL−1on rice. Polysaccharides treated seedling showed elevated activities of peroxidase and polyphenol-oxidase activities, and total-phenols content. Treated plantlets showed up regulation of OsPR1.1,OsPR3, OsGLP3-3,OsZFP179 , and Oshox24 as well as downregulation of OsACS6. Conclusions We showed that P. putida Bp25 and its cell wall-associated polysaccharides could elicit defense against rice blast [ABSTRACT FROM AUTHOR]

Nanotechnology-enabled pesticide delivery systems have been widely studied and show great prospects in modern agriculture. Nanodelivery systems not only achieve the controlled release of agrochemicals but also possess many unique characteristics. This study presents the development of a pH-responsive pesticide nanoformulation utilizing hollow mesoporous silica nanoparticles (HMSNs) as a nanocarrier. The nanocarrier was loaded with the photosensitive pesticide prochloraz (Pro) and then combined with ZnO quantum dots (ZnO QDs) through electrostatic interactions. ZnO QDs serve as both the pH-responsive gatekeeper and the enhancer of the pesticide. The results demonstrate that the prepared nanopesticide exhibits high loading efficiency (24.96%) for Pro. Compared with Pro technical, the degradation rate of Pro loaded in HMSNs@Pro@ZnO QDs was reduced by 26.4% after 24 h ultraviolet (UV) exposure, indicating clearly improved photostability. In a weak acidic environment (pH 5.0), the accumulated release of the nanopesticide after 48 h was 2.67-fold higher than that in a neutral environment. This indicates the excellent pH-responsive characteristic of the nanopesticide. The tracking experiments revealed that HMSNs can be absorbed by rice leaves and subsequently transported to other tissues, indicating their potential for effective systemic distribution and targeted delivery. Furthermore, the bioactivity assays confirmed the fungicidal efficacy of the nanopesticide against rice blast disease. Therefore, the constructed nanopesticide holds great prospect in nanoenabled agriculture, offering a novel strategy to enhance pesticide utilization.

von Willebrand factor A (vWA) genes are well characterized in humans except for few BONZAI genes, but the vWA genes are least explored in plants. Considering the novelty and vital role of vWA genes, this study aimed at characterization of vWA superfamily in rice. Rice genome was found to have 40 vWA genes distributed across all the 12 chromosomes, and 20 of the 40 vWA genes were unique while the remaining shared large fragment similarities with each other, indicating gene duplication. In addition to vWA domain, vWA proteins possess other different motifs or domains, such as ubiquitin interacting motif in protein degradation pathway, and RING finger in protein-protein interaction. Expression analysis of vWA genes in available expression data suggested that they probably function in biotic and abiotic stress responses including hormonal response and signaling. The frequency of transposon elements in the entire 3K rice germplasm was negligible except for 9 vWA genes, indicating the importance of these genes in rice. Structural and functional diversities showed that the vWA genes in a blast-resistant rice variety Tetep had huge variations compared to blast-susceptible rice varieties HP2216 and Nipponbare. qRT-PCR analysis of vWA genes in Magnaporthe oryzae infected rice tissues indicated OsvWA9 , OsvWA36 , OsvWA37 and OsvWA18 as the optimal candidate genes for disease resistance. This is the first attempt to characterize vWA gene family in plant species. [ABSTRACT FROM AUTHOR]