Department of Plant Pathology, Gorgan University of Agriculture Science and Natural Resources , Gorgan, Golestan , Iran.
Braz J Microbiol. 2012 Jan;43(1):297-305. doi: 10.1590/S1517-838220120001000035. Epub 2012 Jun 1.
Brown spot caused by Bipolaris oryzae is an important rice disease in Southern coast of Caspian Sea, the major rice growing region in Iran. A total of 45 Trichoderma isolates were obtained from rice paddy fields in Golestan and Mazandaran provinces which belonged to Trichoderma harzianum, T. virens and T. atroviride species. Initially, they were screened against B. oryzae by antagonism tests including dual culture, volatile and nonvolatile metabolites and hyperparasitism. Results showed that Trichoderma isolates can significantly inhibit mycelium growth of pathogen in vitro by producing volatile and nonvolatile metabolites Light microscopic observations showed no evidence of mycoparasitic behaviour of the tested isolates of Trichoderma spp. such as coiling around the B. oryzae. According to in vitro experiments, Trichoderma isolates were selected in order to evaluate their efficacy in controlling brown spot in glasshouse using seed treatment and foliar spray methods. Concerning the glasshouse tests, two strains of T. harzianum significantly controlled the disease and one strain of T. atroviride increased the seedling growth. It is the first time that the biological control of rice brown spot and increase of seedling growth with Trichoderma species have been studied in Iran.
由串珠镰刀菌引起的褐斑病是里海南岸、伊朗主要水稻种植区的一种重要水稻病害。从戈勒斯坦省和马赞达兰省的稻田中总共获得了 45 个木霉分离物，它们属于哈茨木霉、绿木霉和深绿木霉种。最初，通过对峙培养、挥发性和非挥发性代谢物以及重寄生对它们进行了抗生性筛选，以对抗稻瘟病菌。结果表明，木霉分离物通过产生挥发性和非挥发性代谢物，可显著抑制病原菌的菌丝体外生长。光镜观察没有证据表明测试的木霉属分离物存在对稻瘟病菌的寄生行为，例如缠绕在稻瘟病菌周围。根据体外实验，选择木霉分离物，以便通过种子处理和叶面喷雾的方法在温室中评估它们控制褐斑病的效果。关于温室试验，两种哈茨木霉菌株显著控制了病害，一种深绿木霉菌株增加了幼苗生长。这是在伊朗首次研究木霉属控制水稻褐斑病和增加幼苗生长。
