湖北烟草内生真菌生物多样性和种群结构分析

Biodiversity and community structure of endophytic fungi isolated from Nicotiana tabacum L.

摘要:

[目的]研究传统药用植物烟草（Nicotiana tabacum L.）内生真菌的丰富度，揭示其种群多样性和群落结构，为烟草内生真菌资源的有效利用奠定基础。[方法]采用组织分离法进行烟草内生真菌的分离，通过形态学和分子生物学相结合的方法进行菌株分类鉴定，以香农多样性指数及相对分离频率反映内生真菌物种多样性及分布规律。[结果]从不同组织部位、不同生长时期、不同海拔样地的健康烟草中共分离获得539株内生真菌，根据rDNA-ITS系统发育分析鉴定为31属73种，香农多样性指数为2.78，曲霉属Aspergillus和镰孢属Fusarium为优势菌群，其相对分离频率分别为22.63%和12.99%。其分布规律表现为茎部内生真菌的多样性高于叶部和根部；随着生育期的延长，内生真菌多样性逐步增多；随着海拔高度升高，内生真菌的种类和数量呈现降低的趋势。[结论]烟草内生真菌具有丰富的生物多样性，其分布表现出组织、生长时期、海拔高度专化性。阐明内生真菌在烟草中的分布规律，可以为烟草内生真菌在农业生产领域的开发应用提供科学依据。

Abstract:

[Objective] In order to systematically investigate the richness of endophytic fungi derived from the medicinal plant Nicotiana tabacum L., and to reveal their biodiversity and community structures, the resource library of the tobacco endophytic fungi has been established, to provide a foundation for the development and effective use of the fungal endophytes. [Methods] The tobacco endophytic fungi were isolated by tissue separation method and identified with morphology and molecular biology methods. The Shannon index (H') and relative frequency (RF) were used to reflect the biodiversity and distribution of the tobacco endophytic fungi. [Results] A total of 539 strains were isolated under different tissues, developmental periods, and altitudes. According to morphological characteristics and rDNA-ITS sequences, they were identified as 73 taxa in 31 genera, of which the genera Aspergillus sp. and Fusarium sp. were confirmed as the dominant flora, with the relative frequency values of 22.63% and 12.99%, respectively. Meanwhile, the Shannon diversity index was 2.78, indicating considerable richness of the fungal endophytes. The diversity of the endophytic fungi in stems was higher compared with those of in roots and leaves. With the extension of the developmental period, the diversity of the fungal endophytes increased gradually, whereas the trend of the species diversity index of the fungal endophytes was downward with altitude. [Conclusion] Tobacco endophytic fungi have abundant biodiversity, and their distribution shows the specialization of tissues, developmental periods, and altitudes, respectively. To illustrate the distribution of endophytic fungi in tobacco will provide scientific basis for the development and application of the fungal endophytes in agricultural industry.