Browsing by Author "Samal S."

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    First Report of Phytopythium vexans Causing Gummosis and Root Rot of Khasi Mandarin (Citrus reticulata) in North Eastern States of India
    (American Phytopathological Society, 2024) Singh D.; Sharma S.; Das A.; Thakuria D.; Sahoo L.; Kharbikar L.L.; Samal S.; Chand G.; Bahadur A.; Shakywar R.C.
    [No abstract available]
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    Hydrolytic genes of antagonistic rhizobacteria strains on Fusarium udum causing wilt disease in pigeonpea
    (Springer Science and Business Media Deutschland GmbH, 2024) Samal S.; Singh D.; Upadhyay R.S.; Lokesh Babu P.; Geat N.
    Pigeaonpea is attacked by various diseases, including the wilt disease of pigeonpea caused by Fusarium udum. This disease is a severe pathogen to this crop. This study aims to identify the potential biocontrol agent against wilt disease as a fungicide alternative. Forty-seven isolates were evaluated for antagonistic activity against F. udum by dual culture method. Interaction of F. udum and antagonistic bacteria was studied in potato dextrose agar (PDA) under in vitro conditions and lysis of fungal hyphae was observed by using Scanning Electron Microscope. Dry weight of F. udum mycelium was recorded after 3 days of co-inoculation with the rhizobacteria in PDB. Potential antagonistic bacterial isolates were further used for enzymatic assay in vitro conditions. Molecular characterization of bacteria was done by using primers based on hydrolytic genes like chitinase and 1,3-glucanase related genes, amplified at 402 and 750�bp, respectively. Out of forty-seven bacterial isolates used to assess their antagonistic activity, only eight isolates, viz., Bacillus amyloliquefaciens CFLB 31, Bacillus velezensis CFLB 24, Bacillus subtilis CFLB 11, Stenotrophomonas rhizophila CFLB 26, S. matalophila CFLB 47, Microbacteria sp. CFLB 28, G.nicotiana CFLB 18 and Pseudoarthrobacter sp. CFLB 36 showed the promising antagonistic activity against F. udum with 70�84% inhibition in a dual culture plate assay. Among them, three Bacillus species (B. amyloliquefaciens, B. velezensis, B. subtilis) and S. maltophilia CFLB 47 were found to be the most effective biocontrol agent against F. udum under in vitro conditions. Lysis of fungal hyphae was also noted during interaction of fungus and bacteria on PDA. These isolates were screened for production of hydrolytic enzymes activities and they showed positive for production of pectinase, protease and cellulase under in vitro conditions. These isolates amplified chitinase and ?-1, 3-glucanase-related genes at 402 and 750�bp, respectively. In addition, bacterial strains reduced the mycelium weight of F. udum with the range of 58.42 ? 86.84% during co-inoculation in PDB. However, B. amyloliquefaciens had the highest percentage of biomass reduction, up to 86.84%. Bacterial treatments are considered beneficial and nature-friendly. The results propose that the eight potential strains and their hydrolytic enzymatic properties made them promise to manage wilt disease of pigeonpea. � The Author(s) under exclusive licence to Societ� Italiana di Patologia Vegetale (S.I.Pa.V.) 2024.
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    Unraveling the involvement of WRKY TFs in regulating plant disease defense signaling
    (Springer Science and Business Media Deutschland GmbH, 2024) Saha B.; Nayak J.; Srivastava R.; Samal S.; Kumar D.; Chanwala J.; Dey N.; Giri M.K.
    Main conclusion: This review article explores the intricate role, regulation, and signaling mechanisms of WRKY TFs in response to biotic stress, particularly emphasizing their pivotal role in the trophism of plant-pathogen interactions. Abstract: Transcription factors (TFs) play a vital role in governing both plant defense and development by controlling the expression of various downstream target genes. Early studies have shown the differential expression of certain WRKY transcription factors by microbial infections. Several transcriptome-wide studies later demonstrated that diverse sets of WRKYs are significantly activated in the early stages of viral, bacterial, and fungal infections. Furthermore, functional investigations indicated that overexpression or silencing of certain WRKY genes in plants can drastically alter disease symptoms as well as pathogen multiplication rates. Hence the new aspects of pathogen-triggered WRKY TFs mediated regulation of plant defense�can�be�explored. The already recognized roles of WRKYs include transcriptional regulation of defense-related genes, modulation of hormonal signaling, and participation in signal transduction pathways. Some WRKYs have been shown to directly bind to pathogen effectors, acting as decoys or resistance proteins. Notably, the signaling molecules like salicylic acid, jasmonic acid, and ethylene which are associated with plant defense significantly increase the expression of several WRKYs. Moreover, induction of WRKY genes or heightened WRKY activities is also observed during ISR triggered by the beneficial microbes which protect the plants from subsequent pathogen infection. To understand the contribution of WRKY TFs towards disease resistance and their exact metabolic functions in infected plants, further studies are required. This review article explores the intrinsic transcriptional regulation, signaling mechanisms, and hormonal crosstalk governed by WRKY TFs in plant disease defense response, particularly emphasizing their specific role against different biotrophic, hemibiotrophic, and necrotrophic pathogen infections. � 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.