Assessing the effect of organic residue quality on active decomposing fungi in a tropical Vertisol using 15N-DNA stable isotope probing

15N-DNA stable isotope probing (15N-DNA-SIP) combined with 18S rRNA gene-based community analysis was used to identify active fungi involved in decomposition of 15N-labeled maize and soybean litter in a tropical Vertisol. Phylogenetic analysis of 15N-labeled DNA subjected to 18S rRNA gene-based community fingerprinting showed that addition of maize residues promoted relatively slow-growing fungal decomposers (i.e. Penicillium spp., Aspergillus spp.), while addition of soybean residues promoted relatively fast-growing fungal decomposers (i.e. Fusarium spp., Mortierella spp.). Chaetomium spp. were dominant decomposers in both residue treatments. Therefore, we have clear evidence that specific members of the fungal community used 15N derived from the two organic resources with contrasting biochemical quality for growth. Our study showed that 15N-DNA-SIP-based community analysis is a useful method to follow the fate of N from organic resources into the actively decomposing fungal community of soils.