Fungal endophytic communities of two wild Rosa varieties and the role of an endophytic Seimatosporium sp. in enhancing host plant powdery mildew resistance

Abstract

The aim of the study was to evaluate the possible role of endophytic fungi (EF) on Rosa powdery mildew (PM) resistance. The endophytic fungal communities of two wild Rosa varieties with different PM susceptibilities were investigated through both culture-dependent and independent methods, and the antagonistic activities of endophytes against the PM pathogen were evaluated by pot experiments. There were more OTUs recovered from the PM resistant variety than from the PM susceptible variety. Similarly, the culturable EF from the PM resistant variety (1333 isolates) was more than that from the PM susceptible variety (670 isolates). Consistent with this, the colonization rate of culturable EF of the PM resistant variety was significantly higher than that of the PM susceptible variety at each PM stage (p < 0.05). In addition, it was found that the dominant EF of both varieties were different using culture-dependent and independent methods. The α-diversity of both culturable and un-culturable EF were similar except at the early stage of PM infection. Pot experiments showed that the strain M7SB 41 (Seimatosporium sp.) from PM resistant variety significantly enhanced host plant PM resistance. The results suggested that the endophytic fungal communities of two wild Rosa varieties with different PM susceptibilities were significantly different, and the PM resistant Rosa variety harbored more EF than susceptible Rosa variety, and some EF played an important role in host plant PM resistance.