Senthilkumar M, Swarnalakshmi K, Govindasamy V, Lee Young Keun, Annapurna K
Advanced Radiation Technology Institute, Korean Atomic Energy Research Institute, Jeongeup 580-185, South Korea.
Curr Microbiol. 2009 Apr;58(4):288-93. doi: 10.1007/s00284-008-9329-z. Epub 2008 Dec 9.
A total of 137 bacterial isolates from surface sterilized root, stem, and nodule tissues of soybean were screened for their antifungal activity against major phytopathogens like Rhizoctonia bataticola, Macrophomina phaseolina, Fusarium udam, and Sclerotium rolfsii. Nine bacterial endophytes suppressed the pathogens under in vitro plate assay. These were characterized biochemically and identified at the genus level based on their partial sequence analysis of 16S rDNA. Eight of the isolates belonged to Bacillus and one to Paenibacillus. The phylogenetic relationship among the selected isolates was studied and phylogenetic trees were generated. The selected isolates were screened for biocontrol traits like production of hydrogen cyanide (HCN), siderophore, hydrolytic enzymes, antibiotics, and plant growth promoting traits like indole 3-acetic acid production, phosphate solubilization, and nitrogen fixation. A modified assessment scheme was used to select the most efficient biocontrol isolates Paenibacillus sp. HKA-15 (HKA-15) and Bacillus sp. HKA-121 (HKA-121) as potential candidates for charcoal rot biocontrol as well as soybean plant growth promotion.
从大豆经表面消毒的根、茎和根瘤组织中总共分离出137株细菌，检测它们对主要植物病原体如菜豆丝核菌、菜豆壳球孢菌、乌德镰刀菌和齐整小核菌的抗真菌活性。在体外平板试验中，9株细菌内生菌抑制了这些病原体。对它们进行了生化特性鉴定，并基于16S rDNA的部分序列分析在属水平上进行了鉴定。其中8株分离物属于芽孢杆菌属，1株属于类芽孢杆菌属。研究了所选分离物之间的系统发育关系并构建了系统发育树。对所选分离物进行了生物防治特性筛选，如氰化氢（HCN）产生、铁载体、水解酶、抗生素的产生，以及植物生长促进特性，如吲哚-3-乙酸产生、磷溶解和固氮。采用改良的评估方案选出了最有效的生物防治分离物类芽孢杆菌属HKA-15（HKA-15）和芽孢杆菌属HKA-121（HKA-121），作为防治炭腐病以及促进大豆植株生长的潜在候选菌株。
