Community composition of endophytic fungi in Acer truncatum and their role in decomposition

The mycota and decomposing potential of endophytic fungi associated with Acer truncatum, a common tree in northern China, were investigated. The colonization rate of endophytic fungi was significantly higher in twigs (77%) than in leaves (11%). However, there was no significant difference in the colonization rates of endophytic fungi between lamina (9%) and midrib (14%) tissues. A total of 58 endophytic taxa were recovered using two isolation methods and these were identified based on morphology and ITS sequence data. High numbers of leaf endophytes were obtained in the method to determine decomposition of leaves by the natural endophyte community (35 taxa) as compared to disk fragment methodology (9 taxa). The weight loss in A. truncatum leaves decomposed by endophyte communities increased with incubation time; the weight loss was significantly higher at 20 weeks than at 3 and 8 weeks. Both common and rare endophytic taxa produced extracellular enzymes in vitro and showed different leaf decay abilities. Our results indicated that the composition and diversity of endophytic fungi obtained differed using two isolation methods. This study suggests that endophytic fungi play an important role in recycling of nutrients in natural ecosystems.