The present study aimed to identify, characterize, and evaluate native chitinolytic rhizobacteria as biocontrol potential against pigeon pea wilt disease, caused by Fusarium udum. A total of 53 isolated rhizobacteria was evaluated for their chitinolytic potential and possession of different antifungal traits. From the successive in vitro experiments and in vivo bioassay, 2 promising bacterial strains (NS-1 and NS-22) that exhibited strong chitinolytic activities and mycolytic action were biochemically characterized and identified as Pseudomonas spp. NS-1 (NCBI GenBank accession number- KT175909) and Bacillus spp. NS-22 (NCBI GenBank accession number-MH425454), using 16S rDNA sequencing. In planta, disease severities for Pseudomonas spp. NS-1- and Bacillus spp. NS-22-treated plants were only about 14.62 and 23.08%, respectively, as compared to pathogen-only control (67.34%) at the end of 4 weeks. Additionally, these bacteria improved plant germination and fresh and dry plant biomasses under pathogen-challenged conditions. Further, both the strains were able to cause a considerable amount of reduction in the fungal biomass, as revealed by bacteria-pathogen interaction studies in liquid culture. Scanning electron microscopy studies also revealed the strong antifungal activities of these 2 chitinolytic bacteria on the pathogen hyphae and mycelia. The curling, bulging, breakdown, and other dysfunctionalities in fungal hyphae were induced by the biocontrol bacteria. In nutshell, the present exclusive investigation demonstrated mycolytic potential and biocontrol prospects of the 2 promising bacteria (Pseudomonas spp. NS-1 and Bacillus spp. NS-22) for the sustainable Fusarium wilt management and as a phytostimulator in pigeon pea.

中文翻译：

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天然几丁质分解根瘤菌的分离及其对木豆枯萎病的生防活性和促进植物生长的功效（Cajanus cajan L.）

本研究旨在鉴定，表征和评估天然的几丁质溶菌性根瘤菌，作为对付豌豆枯萎病引起的木豆枯萎病的生物防治潜力。总共评估了53个分离的根瘤菌的几丁质分解能力和具有不同的抗真菌特性。从连续的体外实验和体内生物测定中，对2种有前途的细菌菌株（NS-1和NS-22）表现出强大的几丁质分解活性和霉菌溶解作用进行了生化鉴定，鉴定为假单胞菌。NS-1（NCBI GenBank登录号-KT175909）和芽孢杆菌属。NS-22（NCBI GenBank登录号-MH425454），使用16S rDNA测序。在植物中，Pseudomonas spp的疾病严重程度。NS-1-和芽孢杆菌属。经NS-22处理的植物分别仅为14.62和23.08％，在第4周末与仅病原体对照（67.34％）相比。另外，这些细菌在病原体挑战的条件下改善了植物的发芽以及新鲜和干燥的植物生物量。此外，如液体培养中细菌-病原体相互作用研究所揭示的，两种菌株均能够引起真菌生物量的大量减少。扫描电子显微镜研究还揭示了这两种壳多糖分解细菌对病原菌丝和菌丝体的强抗真菌活性。生防菌可引起真菌菌丝的卷曲，膨出，破裂和其他功能障碍。简而言之，本次独家研究表明了两种有前景的细菌（假单胞菌属NS-1和芽孢杆菌属）的溶菌潜力和生物防治前景。