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Author: search.filters.author.Verma, Praveen K.Subject: search.filters.subject.Bipolaris sorokiniana

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    Functional analysis of SCD1 gene involved in pathogenicity of spot blotch disease of wheat causing fungus Bipolaris sorokiniana
    (Springer Nature Publishing AG, 2022) Singh, Kartar; Aggarwal, Rashmi; Verma, Praveen K.; Verma, Sandhya; Sharma, Sapna; Manjunatha, C.; Choudhary, Manoj; Kulshreshtha, Deepika; Rawat, Kirti
    Spot blotch of wheat is an important disease of wheat mainly of warm and humid areas. Melanin produced by various fungi has an important role to play in survival and longevity of fungal propagules against various environmental stresses through providing structural strength. Melanin production is positively correlated with virulence and conidiogenesis that varies in different isolates of plant pathogenic fungus Bipolaris sorokiniana. Scytalone dehydratase gene (SCD1) plays an important role in synthesis of fungal dihydroxynaphthalene melanin. In this study, the SCD1 gene was isolated, characterized and its DNA sequence along with flanking regions was determined. Structural analysis of gene revealed that 516 bp un-interpreted open reading frame. Sequence analysis showed that SCD1 gene encodes a 180 amino acids putative protein. A comparison of the predicted amino acid sequence and actual nucleotide sequence of the SCD1 gene was made with other fungal reductase genes involved in melanin biosynthesis which indicates 56–98% sequence identity. Targeted disruption of SCD1gene revealed that this gene is necessary for melanin biosynthesis in B. sorokiniana. SCD1 gene mutant isolate lack melanin synthesis and showed significant reduction in pathogenicity on wheat plants. This study expands our knowledge and provides comprehensive understanding of the pathogenesis of B. sorokiniana and insight of fungal phytopathogens.
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    High reliability transformation of the wheat pathogen Bipolaris sorokiniana using Agrobacterium tumefaciens
    (Elsevier, 2012) Nizam, Shadab; Verma, Sandhya; Singh, Kunal; Aggarwal, Rashmi; Srivastava, Krishna Dutt; Verma, Praveen K.
    Bipolaris sorokiniana, the causal agent of spot blotch of wheat, significantly reduces grain yield worldwide. In order to study pathogenic mechanisms of the fungus, conditions for efficient transformation using Agrobacterium-mediated transformation were investigated. To study different stages of hyphal fusion and pathogenic mechanisms of the fungus, two fluorescence markers viz. the red fluorescent protein (DsRed-Ex- press) and the green fluorescent protein (EGFP1) were constitutively expressed. Southern hybridizations confirmed the presence of T-DNA in all hygromycin B or geneticin resistant transformants, and also showed random and single copy integration. Fluorescence microscopy suggested the high level expression of both DsRed and EGFP fluorescent proteins in spores and mycelia. The results signify that DsRed and EGFP can be used as efficient reporter gene for monitoring B. sorokiniana hyphal fusion as well as colonization in the host tissues. This work will be useful to develop methodologies for understanding the mechanisms of Bipo- laris–wheat interaction and functional genomics of B. sorokiniana for various applications including insertion- al mutagenesis, targeted disruption of specific genes, ectopic complementation of loss-of-function strains and over-expression.