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

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.