Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Ministry of Education, Nanjing Agricultural University, Nanjing, China.
Lett Appl Microbiol. 2013 Dec;57(6):526-33. doi: 10.1111/lam.12144. Epub 2013 Sep 17.
Both Bacillus subtilis and harpins stimulate plant growth and defence against various plant pathogens. In this study, B. subtilis 168 and two derivatives, surfactin producer OKB105 and combined surfactin and HpaGX ooc producer OKBHF, were applied to tomato plants to investigate the mechanisms underlying this effect. To evaluate colonization ability, strains were labelled with green fluorescent protein (GFP). Although biofilm distribution of the three strains was similar on root surfaces, Colonization populations of the two surfactin producers were approximately 2- to 3-fold higher than that of strain 168, and this was accompanied by significantly increased tomato growth. These results suggest that efficient colonization, possibly facilitated by surfactin production, enhanced the efficiency of plant growth promotion by B. subtilis. All three B. subtilis treatments caused plants to have less severe disease symptoms after inoculation with Ralstonia solanacearum, with plants treated with OKBHF being the most resistant, suggesting that hpaGX ooc improves biocontrol efficiency of B. subtilis. Analysis of defence-related genes showed a synergistic effect of HpaGX ooc on B. subtilis enhancement of the expression of the pathogenesis-related genes PR1b1 and PR-P2. In contrast, expression of the defence-related genes PINI and PINII was suppressed.
Bacillus subtilis and harpins are biological control agents with respective advantages. In this study, combinations of the both were applied to tomato in the form of hpaGX ooc -expressing B. subtilis, showed much better effects on resistance to wilt disease, and equivalent effects on plant growth promotion compared with the progenitor strain have a great potential in agricultural use.
枯草芽孢杆菌和 harpins 都能刺激植物生长和防御各种植物病原体。在这项研究中，枯草芽孢杆菌 168 及其两个衍生物，表面活性剂产生菌 OKB105 和同时产生表面活性剂和 HpaGX 卵菌产生菌 OKBHF，被应用于番茄植物，以研究这种效应的机制。为了评估定殖能力，菌株用绿色荧光蛋白（GFP）标记。尽管三种菌株在根表面的生物膜分布相似，但两种表面活性剂产生菌的定殖种群约为 168 菌株的 2-3 倍，并且这伴随着番茄生长的显著增加。这些结果表明，有效的定殖，可能通过表面活性剂的产生得到促进，提高了枯草芽孢杆菌促进植物生长的效率。三种枯草芽孢杆菌处理都导致植物在接种茄青枯病菌后症状较轻，用 OKBHF 处理的植物抗性最强，表明 hpaGX 卵菌提高了枯草芽孢杆菌的生物防治效率。防御相关基因的分析表明，HpaGX 卵菌与枯草芽孢杆菌协同作用增强了病程相关基因 PR1b1 和 PR-P2 的表达。相比之下，防御相关基因 PINI 和 PINII 的表达受到抑制。
枯草芽孢杆菌和 harpins 是具有各自优势的生物防治剂。在这项研究中，以表达 hpaGX 卵菌的枯草芽孢杆菌的形式将两者组合应用于番茄，对枯萎病的抗性表现出更好的效果，与亲代菌株相比，对植物生长的促进效果相当，在农业应用中有很大的潜力。
