Molecular Ecology and Evolution
Amma, Sarasa .
Analysis of the composition and diversity of soil fungi in seasonal tropical forests in Thailand with massive parallel DNA sequencing.
Although fungi take essential roles for ecosystems as decomposers, mutualists, and pathogens and have variety of interactions with many other organisms, little is known about the spatial patterns of the diversity of tropical fungi. The aim of this study was to elucidate the composition and diversity of soil fungi of seasonal tropical forests in Northeast Thailand (Sakaerat Environmental Research Station), to explore the effects of forest types (dry deciduous forest [DDF] vs. dry evergreen forests [DEF]). After 10 g of soil were regularly sampled at 50 points at each 50 m × 50 m plot, soils were sieved (≥ 2 mm), and immediately dried with granular silica gel. Fungal DNA was extracted with CTAB method from 2 mL of soil of each sampling point. Fungal ITS2 sequences of the extracted DNA were amplified in PCR, purified by QIAquick PCR Purification Kit, and subjected to the 454 pyrosequencing on a GS Junior sequencer (PCR primers: 1stPCR: Forward: ITS1f-KYO, Reverse: LR3, 2ndPCR: Forward: ITS3-KYO2, Reverse: LR-KYO1b). The reads were assembled by Assams at cutoff similarity of 97%. Chimera reads and samples with fewer than 100 high-quality reads were eliminated. Molecular identification of these OTUs was conducted by Claident. Pyrosequencing analysis yielded 38,737 sequencing reads across the 350 soil samples from all sampling points. Among 818 fungal operational taxonomic units (OTUs), 765 (94%) were identified to phylum, which was the same level with that found from soils of a temperate forest. At phylum level, 70-78% belonged to Ascomycota and 15-23% was Basidiomycota. Of the 818 OTUs, 90 were putatively ectomycorrhizal fungi and 16 arbuscular mycorrhizal fungi based on their taxonomy. Although species richness of soil fungi among 7 forest plots did not vary so much, species composition of soil fungi was significantly different (permanova, p<0.00001) between two forest types and between DDF plots, whereas there is no difference between 3 DEF plots. Species composition of soil fungi was weakly correlated with species composition of tree in 4 DDF plots (Mantel statistic r: 0.3043, significance: 0.0001). Thus aboveground plant species composition could not sufficiently explain underground fungal species composition. Undergrowth dwarf bamboo might contribute to form difference of soil fungal species composition in DDF (r=-0.73). This study disclosed fungal community structure in main seasonal tropical forest types in Thailand.
1 - Kyoto University, Graduate School of Agriculture, Kitashirakawa Oiwake-cho Sakyo-ku , Kyoto, Kyoto, 606-8502, Japan
ITS DNA sequence
Presentation Type: Poster:Posters for Topics
Candidate for Awards:Genetics Section Poster Award