Abstract：
Controlling the hazard of sclerotia produced by the Sclerotinia sclerotiorum is very complex, and it is urgent to adopt an effective method that is harmonious environmentally to control the disease. Among the six isolates isolated from the rhizosphere of lettuce, the isolate HZA84 demonstrated a high activity in its antagonism towards Sclerotinia sclerotiorum in vitro, and produces siderophore. By amplification of internal transcribed spacer (ITS), translation elongation factor 1-alpha (TEF1-α), and RNA polymerase II subunit (RPB2) genes, the isolate HZA84 was identified as Trichoderma asperellum, which was confirmed by analysis of phylogenetic tree. The Scanning electron microscope monitoring detected that the isolate HZA84 spread over the sclerotial surface, thus, damaging, decomposing, and distorting the globular cells of the outer cortex of the sclerotia. The Real-time polymerase chain reaction (RT-qPCR) analysis disclosed the overexpression of two genes (chit33 and chit37) encoding the endochitinase in addition to one gene (prb1) encoding the proteinase during 4 and 8 days of the parasitism behavior of isolate HZA84 on the sclerotia surface. These enzymes aligned together in the sclerotia destruction by hyperparasitism. On the other hand, the pots trial revealed that spraying of isolate HZA84 reduced the drop disease symptoms of lettuce. The disease severity was decreased by 19.33 and the biocontrol efficiency was increased by 80.67% within the fourth week of inoculation. These findings magnify the unique role of Trichoderma in disrupting the development of plant diseases in sustainable ways.
摘要：
控制菌核病产生的菌核的危害是非常复杂的，迫切需要采取一种和谐环境的有效方法来控制这种疾病。在从莴苣根际分离的六个分离物中，分离株HZA84在体外对菌核病的拮抗作用方面表现出很高的活性，并产生铁载体。通过扩增内部转录间隔区(ITS)，翻译延伸因子1-α（TEF1-α），和RNA聚合酶II亚基（RPB2）基因，分离出的HZA84被鉴定为木霉，通过对系统发育树的分析证实了这一点。扫描电子显微镜监测检测到分离物HZA84散布在硬化表面，因此，破坏性,分解，扭曲菌核外皮质的球状细胞。实时聚合酶链反应（RT-qPCR）分析揭示了在菌核表面上的分离株HZA84的寄生行为的4天和8天期间，除了编码蛋白酶的一个基因（prb1）外，还有两个编码内切几丁质酶的基因（chit33和chit37）的过表达。这些酶在超寄生虫的菌核破坏中排列在一起。另一方面,盆栽试验显示，喷洒分离株HZA84减少了莴苣的滴病症状。在接种的第四周内，疾病严重程度降低了19.33，生物防治效率提高了80.67％。这些发现放大了木霉以可持续方式破坏植物病害发展的独特作用。
