Agent Of Blight Research Articles

Investigation of the effectiveness and molecular mechanisms of thiamin priming to control early blight disease in potato.

In several plant species, thiamin foliar application primes plant immunity and can be effective in controlling various diseases. However, the effectiveness of thiamin against potato pathogens has seldom been investigated. Additionally, the transcriptomics and metabolomics of immune priming by thiamin have not previously been investigated. Here, we tested the effect of thiamin application against Alternaria solani, the causal agent of early blight in potato, and identified associated changes in gene expression and metabolite content. Thiamin applied on foliage at an optimal concentration of 10 mM reduced lesion size by ~33%. However, prevention of lesion growth was temporally limited, as a reduction of lesion size occurred when leaves were inoculated 4 h, but not 24 h, following thiamin treatment. Additionally, the effect of thiamin on lesion size was restricted to the application site and was not systemic. RNA-seq analysis showed that thiamin affected the expression of 308 genes involved in the synthesis of salicylic acid, secondary metabolites, fatty acid, chitin, and primary metabolism, and photosynthesis, which were also amongst the thousands of genes differentially regulated in the response to pathogen alone. Several of these genes and pathways were more differentially expressed and enriched when thiamin and the pathogen were combined. Thiamin also delayed the downregulation of photosynthesis-associated genes in plants inoculated with A. solani. Metabolite analyses revealed that thiamin treatment in the absence of pathogen decreased the amounts of several organic compounds involved in the citric acid cycle. We hypothesize that thiamin primes plant defenses through perturbation of primary metabolism.

Transmission of Cryphonectria Hypovirus 1 (CHV1) to Cryphonectria radicalis and In Vitro and In Vivo Testing of Its Potential for Use as Biocontrol Against C. parasitica.

Cryphonectria hypovirus 1 (CHV1) is successful in controlling Cryphonectria parasitica, the causal agent of chestnut blight, but little is known regarding its transmission to other fungi, for example the European Cryphonectria radicalis. In this study, CHV1 was transmitted (circa 200,000-800,000 copies/microliter) to seven C. radicalis isolates from infected C. parasitica. Reverse transmission to virus-free C. parasitica (European 74 testers collection) was achieved, although it was less successful (250-55,000 copies/µL) and was dependent on the vegetative compatibility (VC) group. In C. radicalis, the virus infection led to colony colour change from pink to white and smaller colonies, dependent on the virus concentration. The virus was concentrated in the colony edges, and vertically transmitted to 77% of conidia. However, several in vitro experiments demonstrated that C. radicalis was always outcompeted by the blight fungus, only suppressing the pathogen between its 25-50% inoculum level. It presented good secondary capture only when acting as a pioneer. Two types of in planta assays (individual and challenge inoculations) were undertaken. Cryphonectria radicalis behaved as a saprotroph, while chestnut blight fungus behaved as an aggressive pathogen, and lesions after treatment with C. radicalis were no smaller in general, only when using cut branches. Overall, the results showed that infected C. radicalis was unable to control cankers.

Assessing pesticide residue levels in sweetpotato roots and slips treated with fungicides for management of southern blight and circular spot disease caused by Agroathelia rolfsii.

Since 1971, North Carolina (NC) has been the leading sweetpotato-producing state in the United States (US) and is now producing more than half of the nation's annual output. Due to the high demand for US sweetpotatoes from international markets, NC allocates roughly 40% of its sweetpotatoes for export. However, low fungicide residue limits in primary export markets restricts the ability for NC producers to apply fungicides for disease management during sweetpotato production. Agroathelia rolfsii, the causal agent of southern blight and circular spot, is an important pathogen of sweetpotato. Field experiments were conducted in 2022 and 2023 to quantify the residue amount of various active ingredients and transplant-only vs. bedding and transplant applications when managing A. rolfsii in the field. High-performance liquid chromatography analyses of root and vine samples confirmed that none of the tested active ingredients and application timings resulted in residue numbers exceeding the limits of export markets, except for roots treated with thiabendazole. Results from this study provide information for development of application practices with acceptable residue levels for export markets while effectively managing diseases caused by A. rolfsii.

First report of Exserohilum turcicum causing leaf blight on sudangrass (Sorghum × drummondii) in Mexico

In February 2021, elongated grey lesions with reddish margin were observed on sudangrass (Sorghum × drummondii) leaves, in the municipality of Guasave, Sinaloa, Mexico. These symptoms resembled those of leaf blight caused by Bipolaris and Exserohilum on other grasses. Two fungal isolates were recovered from symptomatic leaves, and their identities were confirmed based on a polyphasic approach. The morphological and phylogenetic analysis of the actin gene (act) and internal transcribed spacer region (ITS) of both isolates revealed their identity as Exserohilum turcicum. A pathogenicity test with a representative isolate confirmed this fungus as the causal agent of leaf blight on sudangrass, as symptoms previously observed in the field were developed on the inoculated plants. The E. turcicum isolate was recovered from the diseased sudangrass plants, fulfilling Koch’s postulates. This is the first report of E. turcicum causing leaf blight on sudangrass in Mexico.

In vitro Efficacy of Different Fungicides against Leaf Blight of Sunflower

Sunflower is one of the major oilseed crops cultivated in India. Alternaria leaf blight is one of the fungal diseases of Sunflower caused due the pathogen Alternaria helianthi, which is one of the significant limitations in the cost-effective cultivation of Sunflower in India. It is estimated that 20 to 80% losses in yield and heavy defoliation have been observed due to A. helianthi causal agent of leaf blight of Sunflower. Present investigation on evaluation on efficacy of different fungicides against leaf blight of Sunflower under in vitro condition by using Completely Randomized Design was conducted at Department of Plant Pathology, Dr. Sharadchandra Pawar College of Agriculture, Baramati during. Under this study seven fungicides viz., Chlorothalonil 75% WP, Hexaconazole 5% EC, Carbendazim+Mancozeb 75% WP, Carbendazim 50% WP, Tebuconazole 25.9% EC, Propiconazole 25% EC and Azoxystrobin 23% SC were evaluated against the pathogen Alternaria helianthi causing leaf blight in Sunflower at their recommended concentration and observation on mean radial mycelial growth and percent mycelial growth inhibition of pathogen was calculated. Results revealed that among various fungicides the three fungicides viz., Hexaconazole 5% EC, Tebuconazole 25.9% EC and Propiconazole 25% EC were found most effective with minimum mean mycelial growth and having maximum and similar (94.44%) percent growth inhibition of pathogen and rest of the fungicides tested were comparatively less effective against the pathogen A. helainthi associated with leaf blight of Sunflower.

Advancements in Bacteriophages for the Fire Blight Pathogen Erwinia amylovora.

Erwinia amylovora, the causative agent of fire blight, causes significant economic losses for farmers worldwide by inflicting severe damage to the production and quality of plants in the Rosaceae family. Historically, fire blight control has primarily relied on the application of copper compounds and antibiotics, such as streptomycin. However, the emergence of antibiotic-resistant strains and growing environmental concerns have highlighted the need for alternative control methods. Recently, there has been a growing interest in adopting bacteriophages (phages) as a biological control strategy. Phages have demonstrated efficacy against the bacterial plant pathogen E. amylovora, including strains that have developed antibiotic resistance. The advantages of phage therapy includes its minimal impact on microbial community equilibrium, the lack of a detrimental impact on plants and beneficial microorganisms, and its capacity to eradicate drug-resistant bacteria. This review addresses recent advances in the isolation and characterization of E. amylovora phages, including their morphology, host range, lysis exertion, genomic characterization, and lysis mechanisms. Furthermore, this review evaluates the environmental tolerance of E. amylovora phages. Despite their potential, E. amylovora phages face certain challenges in practical applications, including stability issues and the risk of lysogenic conversion. This comprehensive review examines the latest developments in the application of phages for controlling fire blight and highlights the potential of E. amylovora phages in plant protection strategies.

Preliminary study on Cyclocodon lancifolius leaf blight and screening of Bacillus subtilis as a biocontrol agent.

This study aimed to identify the pathogen responsible for leaf blight in Cyclocodon lancifolius, investigate its biological characteristics, and identify effective synthetic fungicides. Additionally, this study examined changes in physiological and biochemical indices of leaves following pathogen infection and screened biocontrol bacteria that inhibit the pathogen growth, providing a scientific basis for preventing and managing leaf blight in C. lancifolius. Pathogens were isolated from the interface of healthy and infected leaf tissues and identified through morphological and molecular biological methods. Amplification and sequencing of three genomic DNA regions-internal transcribed spacer region, translation elongation factor 1-α, and glyceraldehyde-3-phosphate dehydrogenase of ribosomal DNA-were performed, followed by the construction of a phylogenetic tree. The biological characteristics of pathogens under various temperature and pH conditions and different nitrogen and carbon sources were analyzed using the mycelial growth rate method. The antifungal effects of 13 chemical agents were evaluated using the poisoned medium method and mycelial growth rate method. Changes in physiological and biochemical indicators post-infection were also assessed. An antagonistic experiment was conducted to screen for biocontrol bacteria. A total of 29 potential pathogenic strains were isolated from infected leaf tissues, with Koch's Postulates confirming Stemphylium lycopersici as a key pathogen causing the disease. Growth analysis of S. lycopersici revealed optimal growth at 20°C and pH 6, with lactose or maltose serving as the most suitable carbon source and histidine as the preferred nitrogen source. Among the 13 synthetic fungicides tested, strain DHY4 exhibited the greatest sensitivity to 400 g/L flusilazole. Significant differences (p < 0.05) were observed in superoxide dismutase, phenylalanine ammonia-lyase, peroxidase, polyphenol oxidase, catalase, and malondialdehyde levels between treated and control groups 3 days post-inoculation. The biocontrol strain DYHS2, identified as a strain of Bacillus subtilis, demonstrated an inhibition rate of 51.80% against S. lycopersici in dual-culture experiments and showed a relative inhibition rate of 78.82% in detached leaf assays. These findings provide valuable insights into the newly identified causal agent of leaf blight in C. lancifolius and its biological characteristics, underscoring the potential of B. subtilis DYHS2 and synthetic fungicides such as flusilazole as effective disease management strategies.

Correction to: First report of Fusarium commune as the causal agent of leaf blight on Centella asiatica (Syn. Hydrocotyle asiatica L.) in Iran

Correction to: First report of Fusarium commune as the causal agent of leaf blight on Centella asiatica (Syn. Hydrocotyle asiatica L.) in Iran

New emerging Pseudomonads as causal agents of bean blight disease

Common bean (Phaseolus vulgaris) production is negatively affected by several bacterial plant diseases. A severe outbreak of bean blight was observed in the nine major bean-producing provinces of Iran during 2021–2022. Necrotic spots were observed on leaves which become necrotic with chlorosis beyond it. One hundred-sixty bacterial strains with a greyish-white colony appearance were consistently isolated from the one-hundred eighteen symptomatic bean leaf, pod, seed and root samples on nutrient agar. All strains were screened for their ability to cause disease bean leaves among which 134 strains induced chlorosis three days after inoculation on bean leaves of cv. Yaghoot followed by necrotic spots on the inoculated sites one week after inoculation. The pathogenic strains clustered in three groups based on phenotypic characters and multilocus sequencing analyses. Three housekeeping genes including gyrB, rpoB, and rpoD of representative strains were partially sequenced. In the phylogenetic tree based on concatenated sequences of these three genes or each gene individually, the strains were divided into three clusters each with high bootstrap support. The first group of the strains clustered with Pseudomonas simiae CCUG 50988T. This is the first report of this species as causal agent of bean blight. The second group clustered close to Pseudomonas alloputida NMI5768T which apparently belong to a new species. The third group clustered in a separate clade in Pseudomonas chlororaphis species which belongs to a new subspecies based on pathogenicity on bean, phenotypic characters, sequences of five housekeeping genes which named as subsp. phaseoli subsp. nov. with the type strain UT-M315.

Biocontrol potential of Bacillus velezensis SEC-024A against southern blight of industrial hemp

Agroathelia rolfsii is the causative agent of southern blight of industrial hemp, which is a soil-borne infection resulting in grave economic losses in industrial hemp (Cannabis sativa L.). Chemical pesticides are currently the primary means of controlling this disease, but their use is harmful to human health as well as to the environment. Urgent action is needed to screen eco-friendly biocontrol agents against this pathogen. An endophytic bacterium SEC-024A was isolated from the leaf tissue of industrial hemp and exhibited a significant antagonistic effect on A. rolfsii, with a plate inhibition rate of 80.5 % and a pot control effect of 74.1 %. Through whole genome sequencing, SEC-024A was identified to be Bacillus velezensis. It contained multiple gene clusters involved in secondary metabolite biosynthesis and the genes that promote plant growth, colonization, and pathogen defense. Bacillus velezensis SEC-024A produces volatile organic compounds (VOCs) that serve as its primary fungistatic agents. Nine VOCs produced by SEC-024A were detected through gas chromatography-mass spectrometry. These VOCs were individually tested for their antifungal effects. Four volatiles, namely isobutyric acid, tiglic acid, trans-2-octenal, and 2-decanone, exhibited notable inhibitory effects on A. rolfsii with EC50 values of 0.012, 0.038, 0.009, and 0.046 μL/mL, respectively. Additionally, trans-2-octenal demonstrated broad-spectrum antifungal activity against various soil-borne pathogens. Together, this study suggests that B. velezensis SEC-024A holds promise as a novel microbial agent for improving plant growth and controlling diseases.

First report of Fusarium commune as the causal agent of leaf blight on Centella asiatica (Syn. Hydrocotyle asiatica L.) in Iran

First report of Fusarium commune as the causal agent of leaf blight on Centella asiatica (Syn. Hydrocotyle asiatica L.) in Iran

Pseudoplagiostoma humilis sp. nov., a New Fungal Species CausingShoot Blight and Dieback in Anacardium humile in Brazil.

The cajuzinho do cerrado (Anacardium humile-Anacardiaceae), a shrub species native to Brazil, is harvested for multiple uses in food and medicine. Members of a harvesting community, near the municipality of Bonito de Minas, Minas Gerais state, Brazil reported characteristic symptoms of shoot blight and dieback reducing pseudofruit and seed production by this plant. This study aimed to identify the etiological agent of this disease. Two fungal isolates were obtained from symptomatic leaf samples and morphologically and molecularly characterized. The fungus was identified, based on morphological analyses, as a probable new species of Pseudoplagiostoma. Phylogenetic analyses based on a combination of DNA sequence data (nuc rDNA ITS1-5.8S-ITS2 region, tef1-α and tub2), confirmed this hypothesis. The isolates obtained were allocated to a distinct, well-supported clade (IB = 0.99, ML = 100%), placed as a unique lineage here proposed as a new species named Pseudoplagiostoma humilis. The pathogenicity test confirmed that this new species was the causal agent of shoot blight and dieback on A. humile. This is the fourteenth Pseudoplagiostoma species reported in the world and the third in Brazil.

Biocontrol of fungal pathogens and growth promotion in the Korean fir (Abies koreana E.H.Wilson) seedling using Bacillus velezensis CE 100

The restoration of the endangered Korean fir (Abies koreana E.H.Wilson) forests requires mass production of high-quality and well-developed seedlings for outplanting. However, phytopathogenic fungal infections lower the survival rate and growth vigor of A. koreana seedlings, frustrating the re-afforestation efforts. This study isolated and identified the phytopathogenic fungi causing seedling blight and wilt diseases in A. koreana seedlings and investigated the potential of Bacillus velezensis CE 100 in controlling the fungal pathogens and promoting seedling growth. Phomopsis mali and Fusarium oxysporum were confirmed as the causal agents of blight and wilt diseases, respectively, and both fungi reduced the survival rate of A. koreana seedlings. B. velezensis CE 100 produced cell wall-degrading enzymes: chitinase, protease, and β-1,3-glucanase, and the bacterial crude enzyme fraction inhibited the spore germination and mycelial growth of P. mali and F. oxysporum in a concentration-dependent manner, causing severe morphological deformations. Consequently, treatment with B. velezensis CE 100 improved the survival rate of seedlings infected with either P. mali or F. oxysporum compared to the control and PB media treatment. The bacterium also increased nutrient availability through ammonia–nitrogen production and phosphate solubilization and produced indole-3-acetic acid (IAA), and its inoculation remarkably improved seedling growth (root and shoot dry weight) compared to the control and PB media treatment group. This is the first study to report P. mali and F. oxysporum as the pathogens causing seedling blight and wilt diseases in A. koreana nursery seedling, and the possibility of using B. velezensis CE 100 to control the fungal pathogens and improve the seedling growth without chemical use.

Neopestalotiopsis rosae, a novel pathogen causing leaf blight and crown rot of strawberries in India

Neopestalotiopsis have been reported to affect sustainable strawberry production across the world. Strawberry leaves with leaf blight symptoms were collected in January 2023 from the nurseries and fields of Department of Horticulture, Gandhi Krishi Vigyan Kendra, GKVK, Bangalore, India. Black conidiomata with slimy black conidial mass was produced upon incubating at 28 ± 2 °C. Conidia were fusoid to ellipsoidal, and comprised five cells. The middle three cells were versicolored. Whereas, the apical and basal cells harboured three to four and one appendages, respectively. Neopestalotiopsis rosae was confirmed based on sequencing of internal transcribed spacer (ITS) region of rDNA, β-tubulin (TUB2) and translation elongation factor 1-alpha (EF1-α) gene regions and phylogenetic analysis. Pathogenicity tests confirmed that Neopestalotiopsis rosae as the inciting agent of leaf blight and crown rot disease in strawberry posing a threat to strawberry production in India.

Synthesis of aspartic acid and tyrosine by the fire blight pathogen Erwinia amylovora is not required for proliferation on apple flower stigmas or virulence in fruitlets.

The Gram-negative bacterium Erwinia amylovora (Ea) is the causal agent of fire blight, a devastating disease of apples and pears. In the fire blight disease cycle, Ea grows in different plant tissues, each presenting a distinct nutrient environment. Here, we investigate the ability of aspartate and tyrosine double auxotroph Ea lines to proliferate on apple flower stigma surfaces representing the epiphytic growth stage of Ea and in developing fruitlets representing one endophytic growth stage of Ea. Heterologous complementation studies in an Escherichia coli aspartate and tyrosine auxotroph verify that Ea aspartate aminotransferase (AspC) and tyrosine aminotransferase (TyrB) act as aspartate and tyrosine amino transferases. Growth analysis reveals that Ea aspC tyrB mutants multiply to near-wild-type levels on apple flower stigmas and immature fruitlets. Ea AspC and TyrB are reciprocally complementing for aspartate and tyrosine synthesis in Ec and in Ea. Ea aspC and tyrB mutants obtain sufficient aspartate and tyrosine to support multiplication on stigma surfaces and virulence in immature fruitlets.

New Detection Methods for Cryphonectria Hypovirus 1 (CHV1) through SYBR Green-Based Real-Time PCR and Loop-Mediated Isothermal Amplification (LAMP).

Some mycoviruses can be considered as effective biocontrol agents, mitigating the impact of phytopathogenic fungi and consequently reducing disease outbreaks while promoting plant health. Cryphonectria parasitica, the causal agent of chestnut blight and a highly destructive pathogen, experienced a notable decrease in its virulence with the identification of cryphonectria hypovirus 1 (CHV1), a naturally occurring biocontrol agent. In this study, two innovative diagnostic protocols designed for the accurate and efficient detection of CHV1 are introduced. The ORF A and ORF B regions of CHV1 are targeted by these techniques, which employ colorimetric loop-mediated isothermal amplification (LAMP) with 2 Colorimetric LAMP Master Mix and real-time quantitative PCR (qPCR) with SYBR Green chemistry, respectively. The LAMP assay presents a discernible color transition, changing from pink to yellow after a 35 min incubation period. Comparative analysis, when assessed against two established reverse transcription-PCR (RT-PCR) techniques, reveals a significant enhancement in sensitivity for both the LAMP approach, which offers a tenfold increase, and the qPCR method, which showcases a remarkable 100-fold sensitivity improvement. Throughout the comparison phase, it was evident that the RT-PCR, LAMP, and qPCR procedures displayed superior performance compared to the Bavendamm test, relying on phenol oxidase activity, effectively distinguishing hypovirulent strains. Consequently, this study introduces two pioneer diagnostic assays for highly sensitive CHV1 detection, representing a substantial advancement in the realm of CHV1 surveillance techniques. These methodologies hold significant promise for enhancing research endeavors in the domain of the biological control of C. parasitica.

Transcription factor binding specificities of the oomycete Phytophthora infestans reflect conserved and divergent evolutionary patterns and predict function

BackgroundIdentifying the DNA-binding specificities of transcription factors (TF) is central to understanding gene networks that regulate growth and development. Such knowledge is lacking in oomycetes, a microbial eukaryotic lineage within the stramenopile group. Oomycetes include many important plant and animal pathogens such as the potato and tomato blight agent Phytophthora infestans, which is a tractable model for studying life-stage differentiation within the group.ResultsMining of the P. infestans genome identified 197 genes encoding proteins belonging to 22 TF families. Their chromosomal distribution was consistent with family expansions through unequal crossing-over, which were likely ancient since each family had similar sizes in most oomycetes. Most TFs exhibited dynamic changes in RNA levels through the P. infestans life cycle. The DNA-binding preferences of 123 proteins were assayed using protein-binding oligonucleotide microarrays, which succeeded with 73 proteins from 14 families. Binding sites predicted for representatives of the families were validated by electrophoretic mobility shift or chromatin immunoprecipitation assays. Consistent with the substantial evolutionary distance of oomycetes from traditional model organisms, only a subset of the DNA-binding preferences resembled those of human or plant orthologs. Phylogenetic analyses of the TF families within P. infestans often discriminated clades with canonical and novel DNA targets. Paralogs with similar binding preferences frequently had distinct patterns of expression suggestive of functional divergence. TFs were predicted to either drive life stage-specific expression or serve as general activators based on the representation of their binding sites within total or developmentally-regulated promoters. This projection was confirmed for one TF using synthetic and mutated promoters fused to reporter genes in vivo.ConclusionsWe established a large dataset of binding specificities for P. infestans TFs, representing the first in the stramenopile group. This resource provides a basis for understanding transcriptional regulation by linking TFs with their targets, which should help delineate the molecular components of processes such as sporulation and host infection. Our work also yielded insight into TF evolution during the eukaryotic radiation, revealing both functional conservation as well as diversification across kingdoms.

Leptoglossus occidentalis Heidemann, 1910 (Hemiptera Coreidae) in Türkiye Its distribution, life cycle, and fungal associations

In this study, the distribution, life cycle and associations with fungi of the alien invasive species Leptoglossus occidentalis Heidemann, 1910 (Hemiptera: Coreidae) in Türkiye were investigated. During the study between 2019 and 2021, we found that the pest has spread almost all over Türkiye. We recorded the presence of the species in 35 provinces. The biological data obtained in the study were divided into ecologically similar sub-regions (Ankara-Çankırı-Kırşehir, Artvin, Isparta-Burdur, Izmir-Aydın-Manisa-Muğla-Antalya) in order to reveal the life cycle of the species. Additionally, host plant and insect samples were examined for the presence of Diplodia sapinea (Fr.) Fuckel (pine shoot blight agent) and entomopathogenic fungi species through morphological and molecular identification methods. Consequently, we found that L. occidentalis has two generations in Türkiye. Timing of the first flight was in early May-mid June and the second generation was from mid-July to late August. Although D. sapinea was detected in some of the sampled host plant tissues, it could not be isolated from L. occidentalis individuals. Accordingly, we did not find any evidence that L. occidentalis vectors D. sapinea although the insect and the fungus cooccurs in sampling areas. On the other hand, its vector potential cannot be ruled out especially during rainy periods. This potential remains as a hypothesis for future studies. Although we detected 25 fungal species isolated from L. occidentalis adults, none of them were entomopathogenic fungal species.

High-Quality Complete Genome Sequence of Xanthomonas phaseoli pv. dieffenbachiae Outbreak Strain D182: The Causative Agent of Anthurium Bacterial Blight in Hawaii

Xanthomonas phaseoli pv. dieffenbachiae (Xpd), the causal agent of anthurium blight, is classified as an A2 quarantine organism on the European and Mediterranean Plant Protection Organization (EPPO) list due to its devastating impact on the anthurium industry. In this study, we sequenced strain D182, representative of the Hawaiian anthurium blight outbreak (1981 to 1986), using PacBio RS II SMRT technology. High-quality de novo assembly of 5,217,888 bp (65% GC) was generated with a mean coverage of 351× using HGAP v4. Strain D182 harbors one plasmid (73.5 kb, 60.8% GC). Average nucleotide identity and digital DNA–DNA hybridization values of 99.86 and 98.9%, respectively, showed close phylogenetic relationships with Xpd strain LMG 695PT. The genome information will be useful in providing insights into the genomic biology, virulence mechanisms, and evolutionary relationships of Xpd and other strains associated with anthurium blight outbreaks worldwide. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Hijacking of the methylglyoxal detoxification pathway: a new tactic of Xoo pathogenesis in rice.

Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial blight (BB), has developed a unique strategy to infect rice by hijacking the host's methylglyoxal (MG) detoxification pathway. This results in an over-accumulation of MG, which facilitates tissue colonization and evasion of host's immune responses. While MG role in abiotic stresses is well-documented, its involvement in biotic stresses has not been extensively explored. Recently, Fu et al. (2024) provided the first evidence of MG role in promoting Xoo pathogenesis in rice. This new virulence strategy contributes to the pathogen's remarkable adaptability and survival. In this mechanism of hijacking of MG detoxification pathway, Xoo induces OsWRKY62.1 to inhibit OsGLY II expression, leading to MG overaccumulation in infected rice cells. This excess MG hinders plant cell organelle function, creating a favorable environment for Xoo by compromising the rice defense system. In this article, we have presented our perspectives on how the BB pathogen adapts its virulence mechanisms to infect and cause disease in rice.