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The work presented here expands our understanding of a novel group of mobile genetic elements called Starships that facilitate the horizontal exchange of numerous genes between fungal pathogens. Our analysis shows that Sanctuary and ToxTA are both active transposons within the Bipolaris sorokiniana genome. We also show that the smaller ToxTA transposon has been independently acquired by two different Starships , namely Sanctuary in B. sorokiniana and Horizon in Pyrenophora tritici-repentis and Parastagonospora nodorum . Outside of ToxTA, these two Starships share no sequence identity. The acquisition of ToxTA by two different mobile elements in three different fungal wheat pathogens demonstrates how horizontal transposon transfer is driving the evolution of virulence in these important wheat pathogens.

Pathogens utilize multiple types of effectors to modulate plant immunity. Although many apoplastic and cytoplasmic effectors have been reported, nuclear effectors have not been well characterized in fungal pathogens. Here, we characterize two nuclear effectors of the rice blast pathogen Magnaporthe oryzae . Both nuclear effectors are secreted via the biotrophic interfacial complex, translocated into the nuclei of initially penetrated and surrounding cells, and reprogram the expression of immunity-associated genes by binding on effector binding elements in rice. Their expression in transgenic rice causes ambivalent immunity: increased susceptibility to M . oryzae and Xanthomonas oryzae pv. oryzae , hemibiotrophic pathogens, but enhanced resistance to Cochliobolus miyabeanus , a necrotrophic pathogen. Our findings help remedy a significant knowledge deficiency in the mechanism of M . oryzae –rice interactions and underscore how effector-mediated manipulation of plant immunity by one pathogen may also affect the disease severity by other pathogens. Plant pathogens secrete various effectors to manipulate host immunity. Here, Kim et al. describe two Magnaporthe oryzae effectors that translocate into the nuclei of infected rice cells and reprogram expression of immunity-associated genes, increasing susceptibility to hemibiotrophic pathogens.

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

Wheat is among the ten top and most widely grown crops in the world. Several diseases cause losses in wheat production in different parts of the world. Bipolaris sorokiniana (teleomorph, Cochliobolus sativus ) is one of the wheat pathogens that can attack all wheat parts, including seeds, roots, shoots, and leaves. Black point, root rot, crown rot and spot blotch are the main diseases caused by B. sorokiniana in wheat. Seed infection by B. sorokiniana can result in black point disease, reducing seed quality and seed germination and is considered a main source of inoculum for diseases such as common root rot and spot blotch. Root rot and crown rot diseases, which result from soil-borne or seed-borne inoculum, can result in yield losses in wheat. Spot blotch disease affects wheat in different parts of the world and cause significant losses in grain yield. This review paper summarizes the latest findings on B. sorokiniana , with a specific emphasis on management using genetic, chemical, cultural, and biological control measures.

In a previous study, we reported an alkaliphilic and thermostable endoglucanase (BsGH7-3) of glycoside hydrolase family 7 (GH7) from the hemibiotrophic plant pathogen Bipolaris sorokiniana. However, the catalytic efficiency of the enzyme was lower than for some other endoglucanases of the GH7 family reported in the literature. To engineer a more active enzyme, we identified conserved residues in the substrate-binding tunnel and on the surface of the protein that could play a role in charge-charge interaction and stabilize the structure. The mutants D257W and Q225H in the substrate-binding tunnel and Y222R and Q401N on the protein surface showed a 2-fold increase in specific activity and a 1.5-fold increase in turnover number and were active over a broader range of pH. The mutants also showed a higher tolerance to NaCl. The rational design of the BsGH7-3 mutants helped in increasing the catalytic efficiency of the thermostable enzyme and may be useful in combination with other cellulases like cellobiohydrolase and β-glucosidase towards complete saccharification of cellulose into glucose.

Abstract Wheat and barley serve as significant nutrient-rich staples that are extensively grown on a global scale, spanning over 219 million hectares. The annual combined global yield is 760.9 million tons, with Kazakhstan contributing 14.3 million tons of wheat and 3.83 million tons of barley to this total. The productivity of grain crops has declined annually due to fungal disease, especially root and crown rot caused by Bipolaris sorokiniana and Fusarium spp. Research has focused on pinpointing the pathogens responsible for common root rot in various types of wheat and barley grown in Southeast Kazakhstan. The main goal was to examine the efficacy of certain chemical and biological substances in safeguarding barley seedlings during the early growth stage against root rot root rot. Moreover, this study sought to gauge their effects on seed quality by examining aspects such as germination rates, the colonization of seeds by particular fungal pathogens, and the overall vitality of seeds and seedlings. Visual inspection of the plants revealed that the prevalence of B. sorokiniana was an average of 51.8%, and that of Fusarium species was 58.6%. Three isolates were obtained from the roots of the winter wheat promising line 231, three from the spring wheat roots of the Kazakh variety 10, four from the winter wheat variety Steklovidnaya variety 24, fourteen from the spring barley variety Symbat, and fourteen from the winter barley variety Aidyn variety 2. The external spread of common root rot on spring wheat and spring barley varieties reached 50% and 53%, respectively. Promising line 231 of winter wheat and variety Kazakh 10 of spring barley were affected by the disease by 60%, whereas the winter wheat Steklovidnaya 24 was impacted by 67%. Molecular analysis of B. sorokiniana isolates via species-specific primers (COSA_F/COSA_R) from infected plant tissues confirmed their identification. Koch postulates were fulfilled for B. sorokiniana isolates Kz 48, 60, and 82 on Steklovidnaya 24 winter wheat and Symbat spring barley varieties. Biological products such as Phytosporin-M and Sporobacterin-Rassada significantly reduced the level of fungal infection, confirming their potential as environmentally safe plant protection agents. Resumo O trigo e a cevada são alimentos básicos ricos em nutrientes, cultivados extensivamente em escala global, abrangendo mais de 219 milhões de hectares. A produção global combinada anual é de 760,9 milhões de toneladas, com o Cazaquistão contribuindo com 14,3 milhões de toneladas de trigo e 3,83 milhões de toneladas de cevada para esse total. A produtividade das culturas de grãos diminui anualmente devido a doenças fúngicas, especialmente podridões de raízes e copas causadas por Bipolaris sorokiniana e Fusarium spp. A pesquisa se concentrou em identificar os patógenos responsáveis pela podridão radicular comum em vários tipos de trigo e cevada cultivados no sudeste do Cazaquistão. O objetivo principal era examinar a eficácia de certas substâncias químicas e biológicas na proteção das mudas de cevada durante o estágio inicial de crescimento contra a podridão das raízes. Além disso, o estudo procurou avaliar os seus efeitos na qualidade das sementes, examinando aspectos como as taxas de germinação, a colonização das sementes por determinados fungos patogênicos e a vitalidade geral das sementes e mudas. A inspeção visual das plantas indicou prevalência média de B. sorokiniana de 51,8% e de espécies de Fusarium de 58,6%. Três isolados foram obtidos a partir de raízes da linha promissora de trigo de inverno 231, e três de raízes de trigo de primavera da variedade cazaque 10, quatro de trigo de inverno variedade Steklovidnaya 24, quatorze de cevada de primavera variedade Symbat e quatorze de cevada de inverno variedade Aidyn 2. A disseminação externa da da podridão radicular comum nas variedades de trigo de primavera e cevada de primavera foi de 50% e 53%, respectivamente. A linha promissora 231 de trigo de inverno e a variedade cazaque10 de cevada de primavera foram afetadas pela doença em 60% das unidades, enquanto o trigo de inverno Steklovidnaya 24 foi afetado em 67% das unidades. A análise molecular de isolados de B. sorokiniana, utilizando primers específicos da espécie (COSA_F/COSA_R) de tecidos vegetais infectados, confirmou sua identificação. Os postulados de Koch foram cumpridos para os isolados de B. sorokiniana Kz 48, 60 e 82 em variedades de trigo de inverno Steklovidnaya 24 e cevada de primavera Symbat. Produtos biológicos como Fitosporin-M e Sporobacterin-Rassada reduziram significativamente o nível de infecção fúngica, confirmando seu potencial como agentes de proteção de plantas ambientalmente seguros.

Polyketide–terpenoid hybrid compounds are one of the largest families of meroterpenoids, with great potential for drug development for resistant pathogens. Genome sequence analysis of secondary metabolite gene clusters of a phytopathogenic fungus, Bipolaris sorokiniana 11134, revealed a type I polyketide gene cluster, consisting of highly reducing polyketide synthase, non-reducing polyketide synthase, and adjacent prenyltransferase. MS- and UV-guided isolations led to the isolation of ten meroterpenoids, including two new compounds: 19-dehydroxyl-3-epi-arthripenoid A (1) and 12-keto-cochlioquinone A (2). The structures of 1–10 were elucidated by the analysis of NMR and high-resolution electrospray ionization mass spectroscopy data. Compounds 5–8 and 10 showed moderate activity against common Staphylococcus aureus and methicillin-resistant S. aureus, with minimum inhibitory concentration (MIC) values of 12.5–100 μg/mL. Compound 5 also exhibited activity against four clinical resistant S. aureus strains and synergistic antifungal activity against Candida albicans with MIC values of 12.5–25 μg/mL. The biosynthetic gene cluster of the isolated compounds and their putative biosynthetic pathway are also proposed.Key Points• Ten meroterpenoids were identified from B. sorokiniana, including two new compounds.• Cochlioquinone B (5) showed activity against MRSA and synergistic activity against C. albicans.• The biosynthetic gene cluster and biosynthetic pathway of meroterpenoids are proposed.• Genome mining provided a new direction to uncover the diversity of meroterpenoids.

Key messageA new spot blotch (Bipolaris sorokiniana) resistance gene Sb4 was mapped in a genomic interval of 1.34 Mb on wheat chromosome 4BL.Spot blotch, caused by Bipolaris sorokiniana, has emerged as a serious concern for cultivation of wheat in warmer and humid regions of the world, which results in substantial yield losses and descends with quality. In this study, we identified and mapped a spot blotch resistance gene, designated as Sb4, against B. sorokiniana in wheat. Bulked segregant RNA-Seq (BSR-Seq) analysis and single-nucleotide polymorphism mapping showed that Sb4 is located on the long arm of chromosome 4B. A genetic linkage map of Sb4 was constructed using an F4 mapping population developed from the cross between ‘GY17’ and ‘Zhongyu1211,’ and Sb4 was delimited in a 7.14-cM genetic region on 4BL between markers B6811 and B6901. Using the Chinese Spring reference sequences of chromosome arm 4BL, 13 new polymorphic markers were developed. Finally, Sb4 was mapped in a 1.19-cM genetic interval corresponding to a 1.34-Mb physical genomic region of Chinese Spring chromosome 4BL containing 21 predicted genes. This study provides a foundational step for further cloning of Sb4 using a map-based approach.

Eukaryotic organisms activate conserved signalling networks to maintain genomic stability in response to DNA genotoxic stresses. However, the coordination of this response pathway in fungal pathogens remains largely unknown. In the present study, we investigated the mechanism by which the northern corn leaf blight pathogen Setosphaeria turcica controls maize infection and activates self‐protection pathways in response to DNA genotoxic insults. Appressorium‐mediated maize infection by S. turcica was blocked by the S‐phase checkpoint. This repression was dependent on the checkpoint central kinase Ataxia Telangiectasia and Rad3 related (ATR), as inhibition of ATR activity or knockdown of the ATR gene recovered appressorium formation in the presence of genotoxic reagents. ATR promoted melanin biosynthesis in S. turcica as a defence response to stress. The melanin biosynthesis genes StPKS and StLac2 were induced by the ATR‐mediated S‐phase checkpoint. The responses to DNA genotoxic stress were conserved in a wide range of phytopathogenic fungi, including Cochliobolus heterostrophus, Cochliobolus carbonum, Alternaria solani, and Alternaria kikuchiana, which are known causal agents for plant diseases. We propose that in response to genotoxic stress, phytopathogenic fungi including S. turcica activate an ATR‐dependent pathway to suppress appressorium‐mediated infection and induce melanin‐related self‐protection in addition to conserved responses in eukaryotes. In response to genotoxic stress, the northern corn leaf blight pathogen Setosphaeria turcica activates an ATR‐dependent pathway to suppress appressorium‐mediated infection and induces melanin‐related self‐protection.

Aim: The present study aimed to investigate the inter-relation of different light and nutritional sources on the sporulation of fungus. Methodology: Two isolates of Bipolaris oryzae collected from IIRR, Hyderabad and Lonavala were used in the present study. These isolates were cultured on routine culture media-potato dextrose agar for five days and irradiated with different regimes of near ultraviolet (NUV), ultraviolet and visible light to assess their ability to induce sporulation in fungus. With standardized light source (exposure of fungus to NUV 12hr and 12 hr of darkness), different stresses such as nutrient stress, cold and heat stresses were assessed for its ability to support the abundant sporulation. Results: The enhanced sporulation in B. oryzae (55.9x104 and 36.2x104 spores ml-1, respectively, in IIRR and Lonavala isolates) was obtained by culturing fungus on rabbit food agar media for five days under darkness and later 12 hr alternate exposure of near ultraviolet light and darkness. Interpretation: The maximum sporulation obtained in the present study used in pathogenesis test can be employed in screening programme for identification of resistant genotype for brown spot disease. Key words: Brown spot, Bipolaris oryzae, Nutrition, Rice, Sporulation