Dynamic changes in fungal community structure in rhizosphere soils of transgenic rice with antifungal genes

The effects of transgenic rice with antifungal genes on fungal community structure and the amounts of cultivable fungi in rhizosphere soils were investigated using classical plate counting and denaturing gradient gel electrophoresis (DGGE). Two varieties of transgenic rice ("ZP-1" and "ZP-8") were tested and compared with their controls "QS" of non-transgenic variety. The results showed that no significant differences existed between the amounts of cultivable fungi in rhizosphere soils of transgenic rice and non-transgenic rice at the same growth stages. This suggested that transformation of antifungal genes into rice had no significant effect on the amounts of cultivable fungi in rhizosphere soils. Fungal 18S rRNA DGGE profile showed that the number and relative positions of DGGE bands in rhizosphere soils were similar for transgenic and non-transgenic rice at the same growth stages. This also implied that the transformation of antifungal genes into rice had no significant effect on fungi community structure in rhizosphere soils. Dynamic changes in Shannon diversity and evenness indexes of fungal communities in rhizosphere soils showed no notable differences between transgenic and non-transgenic rice at the same growth stages. It implied that transformation of antifungal genes into rice also had no significant effect on the amounts and community structure of fungi in rhizosphere soils. The study also excised, cloned and sequenced different DGGE bands denoting varying phylotypes. Phylogenetic analysis of cloned bands showed that fungal phylotypes were made up of five phyla- Ascomycota, Basidiomycota, Chytridiomycota, Zygomycota and an unknown fungi.