Interactions between bacteria and fungi in macrophyte leaf litter decomposition

Abstract

Microbes play an important role in decomposition of macrophytes in shallow lakes, and the process can be greatly affected by bacteria-fungi interactions in response to material composition and environmental conditions. In this study, microbes involved in the decomposition of leaf litter from three macrophyte species, Zizania latifolia, Hydrilla verticillata and Nymphoides peltata, were analysed at temperatures of 5, 15 and 25 °C. Results indicate that the decomposition rate was affected by temperature. Bacterial alpha diversity increased significantly along the time, while both temperature and plant species had a significant impact on the bacterial community, and plant type was shown to be the most important driving factor for the fungal community. The cosmopolitan bacterial taxa affiliated with Gammaproteobacteria, Bacteroidetes, Deltaproteobacteria, Firmicutes and Spirochaetes were key species in the investigated ecological networks, demonstrating significant co-occurrence or co-exclusion relationships with Basidiomycota and Ascomycota, according to different macrophyte species. This study indicates that bacteria involved in the decomposition of macrophyte leaf litter are more sensitive to temperature variance, and that fungi have a higher specificity to the composition of plant materials. The nutrient content of Hydrilla verticillata promoted a positive bacteria-fungi interaction, thereby accelerating the decomposition and re-circulation of leaf litter.