ENDOPHYTIC FUNGI COMMUNITY IN Eremanthus erythropappus TREE FROM ANTHROPOGENIC AND NATURAL AREAS OF MINAS GERAIS

ABSTRACT It is know that many plants live in symbiosis with microorganisms that can be found on their interior, the endophytes. Environment and tissue type are modulating factors of this community, in which most of these microorganisms produce important antimicrobial molecules and they may be powerful biocontrol agents in agriculture. Thus, the aim of this study was to evaluate the community of Endophytic fungi from Eremanthus erythropappus in anthropogenic and natural areas (with human interaction, natural habitat and planned planting) of Minas Gerais State, Brazil, through cultivation-based approach and verify their antimicrobial activity against phytopathogenic fungal and pathogenic bacteria. The endophytic fungi isolated were identified by sequencing of the ITS region and subjected an in vitro antagonism test. The antagonisms that show antibiosis were submitted to tests on split plates to verify the volatile compound production. In the pairing testes, the endophytic fungi of the genera Cryptosporiopsis, Diaporthe, Xylaria, Paraconiothyrium and Camarosporium presented antibiosis against phytopathogenic fungi by releasing compounds in the medium. To our knowledge, this paper is the first report on the isolation of twelve genera fungi in E. erythropappus besides verifying their antagonist capacity, which opens the way for discovery of bioactive substances produced by endophytic fungi that inhibit pathogens.

摘要
众所周知，诸多植物与其体内的微生物（即内生菌（endophytes））形成共生关系。环境与组织类型是调控该微生物群落的关键因素，其中绝大多数内生菌可产生具有重要活性的抗菌分子，有望成为农业领域极具应用潜力的生物防治剂。
为此，本研究以巴西米纳斯吉拉斯州（Minas Gerais State）人为干预区与自然区域（涵盖受人类活动干扰的自然生境、原生自然栖息地及规划种植林）中的红脉乳木（Eremanthus erythropappus）为研究材料，采用基于培养的研究方法（cultivation-based approach）解析其内生真菌群落结构，并验证这些内生真菌对植物病原真菌与致病细菌的抗菌活性。
所分离获得的内生真菌通过ITS区域（Internal Transcribed Spacer region）测序完成物种鉴定，并开展体外拮抗试验。对表现出抗生作用的拮抗菌株，进一步采用分隔平板试验（split plates test）验证其挥发性代谢产物的产生情况。
在配对拮抗试验中，隶属于隐孢壳属（Cryptosporiopsis）、间座壳属（Diaporthe）、炭棒属（Xylaria）、副小壳属（Paraconiothyrium）及棒孢属（Camarosporium）的内生真菌，可通过向培养基中释放代谢产物，对植物病原真菌产生抗生作用。
据我们所知，本研究首次在红脉乳木中分离得到12个属的真菌，并验证了它们的拮抗能力，这为发掘内生真菌所产生的抑制病原菌的生物活性物质开辟了全新路径。