Biocontrol of bacterial canker/wilt of tomato (Lycopersicum esculentum) caused by Clavibacter michiganensis subsp. michiganensis with rhizobacteria

密歇根乳杆菌亚种。番茄青枯病是番茄青枯病和溃烂病的病原菌，在世界范围内造成巨大的经济损失。在过去的十年中，对番茄CMM的研究主要集中在流行病学方面，而对生物防治的研究很少。人们对有机生产番茄的兴趣与日俱增，生物防治与这种方法是兼容的。这项建议的目的是筛选植物根际对CMM有拮抗作用的细菌，并研究它们保护番茄植株免受CMM侵染的能力。我们建议从根际土壤和植物根样本中分离出根附生和内生细菌。然后将对这些分离物进行抗CMM活性筛选。在这方面的第一次小规模努力发现了四个菌株显示出抗CMM活性，然而，必须确定广泛的菌株，因为由于应用和产品限制以及监管限制，肯定会发现一些菌株不适合商业生物防治；从一开始就大量使用是最佳策略。活性菌株将使用高效液相色谱、气相色谱/质谱仪、MALDI-TOF和/或核磁共振光谱分析，以产生抗菌化合物。这些化合物的抗CMM活性将通过纸片扩散法(在琼脂平板上)进行评估，并确定每个化合物的最低抑制浓度。我们还将研究生防菌及其抗CMM化合物的抗CMM活性。此外，我们还将研究生防菌/抗CMM化合物、CMM和寄主番茄植物之间的三方关系。将进行温室研究，以研究生防菌及其抗生素在一系列组合中的应用地点(种子、根、叶及其各种组合)，以控制CMM。我们还将确定这些细菌/抗CMM化合物是否能够诱导番茄植株产生抗病能力，从而增加寄主植物对病原菌的防御活性。最后，生防菌/抗CMM化合物防治CMM的研究将在类似于商业温室的条件下进行。

Clavibacter michiganensis subsp. michiganensis (Cmm) is the causal agent of bacterial wilt and canker of tomato (Lycopersicon esculentum), causing substantial economic losses worldwide. During the last decade research work on Cmm of tomato has largely focused on epidemiology, however, there has been little research on biological control. There is growing interest in organic production of tomatoes and biocontrol is compatible with this approach. The goal of this proposal is to screen plant rhizospheres for bacteria antagonistic to Cmm, and to investigate their ability to protect tomato plants against Cmm. We propose to isolate root epiphytic and endophytic bacteria from rhizosphere soil and plant root samples. These isolates will then be screened for activity against Cmm. A first small effort in this regard discovered four strains that show anti-Cmm activity, however, a wide range of strains must be identified as some are certain to be found unsuitable for commercial biocontrol, due to an application and product constraints, and to regulatory restrictions; a large number at the outset is the best strategy. The active strains will be analyzed for production of anti-bacterial compounds using HPLC, GC/MS and MALDI-TOF and/or NMR spectroscopy. The anti-Cmm activity of these compounds will be assessed via the disk diffusion assay (on agar plates), and the minimum inhibitory concentration of each will be determined. We will also study the anti-Cmm activity of combinations of biocontrol bacteria and their anti-Cmm compounds. In addition, we will study the tripartite association of the biocontrol strains/anti-Cmm compounds, Cmm and the host tomato plant. Greenhouse studies will be conducted to study application sites (seed, root, foliar and various combinations of these) for biocontrol bacteria and their antibiotics in a range of combinations, for the control of Cmm. We will also determine if these bacteria/anti-Cmm compounds are able to induce disease resistance in tomato plants, thus adding to host plant defense activity against the pathogen. Finally, studies on the control of Cmm by biocontrol strains/anti-Cmm compounds will be conducted under conditions similar to commercial greenhouses.