Diversity and decomposition potential of endophytes in leaves of a Cinnamomum camphora plantation in China

This study was carried out to improve our understanding of the diversity and decomposition potential of endophytes in the leaves of Cinnamomum camphora trees grown in a subtropical region of China. We isolated and identified endophytic fungi from senescent leaves of C. camphora and tested their role in decomposition through pure-culture and pre-colonization. A total of 2,861 endophytic fungi isolated from 69 leaves of C. camphora were grouped into 39 taxa comprising 36 Ascomycetes and 3 Basidiomycetes based on sporulation and ITS sequence analysis. Of these, Colletotrichum gloeosporioides was the most common species (69% relative abundance and 96% colonization frequency), followed by Cladosporium sp.1, Colletotrichum sp. and Chaetomium sp. All 39 endophytes had the ability to decompose C. camphora leaf litter in pure culture, and a few exhibited >20% litter mass loss in 2 months. In most cases, single endopyhytic species showed lower mass loss than mixed microbial groups from active soil after 60 or 120 days. In pre-inoculation, endophytic fungi like Chaetomium sp., Cladosporium sp.1, C. gloeosporioides, Colletotrichum sp. and Guignardia sp. exhibited higher abundance and caused greater mass loss, indicating the potential of these groups to enter and significantly accelerate the process of decomposition. This study concludes that, after entering the decomposition process, selected endophytic fungi with high abundance could influence significantly the decomposition process and thus probably affect carbon and nutrient cycling in C. camphora plantations.