疯草是天然草地主要毒草，家畜误食导致中毒或死亡，我国因之每年损失二十多亿。疯草的主要毒性为苦马豆素，而疯草内生真菌是此类疯草毒性的主要原因，已发现于国外20种和我国8种疯草，均属于同一种真菌，存在丰富的形态、生理、生态和遗传多样性。然而，由于对其发生规律缺乏深入研究，目前尚无法防除。发生规律中最大的难点为传播环节，已报道其仅通过种子垂直传播，但该观点与疯草内生真菌已分布于不同地区不同疯草体内的现实存在矛盾。本项目申请人近期研究发现其既可在植株上产孢，又可发生侵染，故存在水平传播，并提出假设：其多样性形成的原因可能与水平传播有关。本项目拟采用田间调查、室内接种、分离培养、菌株杂交、PCR检测、基因测序等方法，研究我国8种疯草中内生真菌的产孢能力、侵染能力、寄主范围等水平传播机理，以及水平传播对其种内多样性的影响，旨在阐明疯草内生真菌在我国的水平传播地区、条件和规律，为有效防治提供理论依据。

Locoweed is the main toxic plants on grassland. Livestock would be poisoned or killed. The annual loss caused by locoweed was more than 2 billion RMB in China. Sainsonine is the main toxic substance, and their endophyte was the the key reason of the toxicity of locoweed. Up to data, they were isolated from twenty locoweed species or varieties, and assigned as a same fungal species (Undifilum oxytropis), which 8 locoweed species from China. The strategies for pest management are mainly based on their occurrence dynamics. However, locoweed and locoweed endophyte can not control effectively since the dynamics of endophyte has not been studied intensively. Transmission is the most difficult in the dynamics. Some studies reported locoweed endophyte was transmitted by seeds only. Nevertheless, it can not explain why they exist in different locoweed all of world, and they were diversity in ecological, morphological, physiological and genetical aspects. The applicant of this project found that locoweed endophyte can transmit horizontally. Based on the finding, a hypothesis is presented: the diversity of locoweed endophyte possibly has some association with horizontal transmission of endophyte. This project is going to study transmission mechanism of locoweed endophyte from 8 locoweed from China, including the sproulation capacity, infection ability, and host range, to study the effect of horizontal transmission on the diversity, with the methods of field investigation, artifical inoculation, isolation, PCR detection, hybrid between isolates, gene sequencing. The objective of this project is to determine the geographical area, conditions, dynamics, and to provide information to manage locoweed endophyte.