Molecular Characterization of Fungal Communities in Non-Tilled, Cover-Cropped Upland Rice Field Soils

This study aimed to characterize soil fungal communities in upland rice fields managed with tillage/non-tillage and winter cover-cropping (hairy vetch and cereal rye) practices, using PCR-based molecular methods. The study plots were maintained as upland fields for 5 years and the soils sampled in the second and fifth years were analyzed using T-RFLP (terminal restriction fragment length polymorphism) profiling and clone libraries with the internal transcribed spacer (ITS) region and domain 1 (D1) of the fungal large-subunit (fLSU) rRNA (D1(fLSU)) as the target DNA sequence. From the 2nd-year-sample, 372 cloned sequences of fungal ITS-D1(fLSU) were obtained and clustered into 80 non-redundant fungal OTUs (operational taxonomic units) in 4 fungal phyla. The T-RFLP profiling was performed with the 2nd- and 5th-year-samples and the major T-RFs (terminal restriction fragments) were identified using a theoretical fragment analysis of the ITS-D1(fLSU) clones. These molecular analyses showed that the fungal community was influenced more strongly by the cover-cropping than tillage practices. Moreover, the non-tilled, cover-cropped soil was characterized by a predominance of Cryptococcus sp. in the phylum Basidiomycota. We provided a genetic database of the fungal ITS-D1(fLSU)s in the differently managed soils of upland rice fields.