海南岛地处热带北缘，自然条件独特，微生物资源丰富，大量未知乳酸菌有待发掘。附着于牧草表面的乳酸菌在青贮发酵中发挥着重要作用，本团队前期研究表明热带牧草中可能存在着能够促进发酵并具有适应高温、高效降解纤维的乳酸菌菌群，但对其遗传多样性和作用机制仍不清楚。本项目拟通过传统微生物学和分子生物学以及第三代16S全长高通量测序相结合的手段对海南岛不同区域（东部海岸平原湿热区、西部丘陵干旱区、南部沿海台地温暖潮湿区、北部沿海台地半湿热区、中部山地潮湿区）牧草附着乳酸菌的菌群表型特征、系统分类特征和基因多样性进行研究，探索热带牧草乳酸菌的系统发育和进化机制；同时分离并筛选温度适应阈值宽、高产纤维素酶的优良乳酸菌菌株；将获得的优良菌株进行热带牧草青贮，分析青贮发酵品质、微生物组成和代谢产物，研究其作用机理。本项目可为发掘利用热带乳酸菌种质资源，新型青贮添加剂研发提供科学依据。

Hainan island located in the north edge of the tropics, with unique landform and climate types and enjoying the richest biodiversity of microorganism resources, we can expect a large number of new lactic acid bacteria (LAB) resources to be discovered. LAB accreted on grass surface, which is a key factor affected the silage fermentation quality. Base on the previous research experience, the project will conduct to investigate the biodiversity of LAB accreted on the tropical grass growing at different ecological regions by using traditional culturing method, biological method and 16S High-throughput sequencing (PacBioⅡ), so that to clarify the changes in germ plasm of LAB with different ecological regions. At the same time, characterizing and identifing some LAB strains with merits and advances in temperature adaptation and produce cellulose. Then, these strains applied to tropical forage silage and evaluate the fermentation quality, nutritional value, aerobic stability and microbial composition. The above reserach are supposed to set up the tropics LAB germplasm resources pool, revealed the genetic diversity of LAB from tropical grass and its regional characteristic, provided an important scientific basis to explore and utilization of tropical LAB germplasm resources and development of the new LAB silage additive product.