Structure and Diversity of Phyllosphere Fungal Communities of Rubber Tree Powdery Mildew
The dominant phyla in all four regions were Ascomycota andBasidiomycota . At the genus level, Erysiphe andCladosporium were dominant, with differing subdominant genera between regions.
Erysiphe was still present in healthy leaves, and so it is speculated that they persist in healthy leaves which do not develop the disease. Compared with these healthy leaves, the relative abundance ofErysiphe on Level 3-infected leaves was significantly higher in all four sampled regions. The relative abundance of Cladosporiumincreased significantly in DZ and decreased significantly in the other three regions. In both BS and WN, the abundance of most fungal taxa declined as Erysiphe became more abundant, which suggested competitive interactions between them.
The fungal community composition and relative abundance varied significantly at the genus level among regions; however, it was similar between Level 3-infected and healthy leaves within the same region. This suggested that powdery mildew did not affect the structure of fungal communities but only the relative abundance of taxa members in each community.
The taxonomic status of many bacteria and fungi in this study has not been identified, so further analysis of the specific relationships between powdery mildew and these taxa is challenging. Advances in biotechnology tools will eventually lead to the development and utilization of these difficult-to-cultivate microorganisms, enabling further research.