抗真菌转基因水稻根际土壤真菌群落结构的动态变化

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

  • 摘要: 以非转基因水稻"七丝软粘"为对照, 采用传统平板计数法和变性梯度凝胶电泳技术, 研究了抗真菌转基因水稻"转品1"和"转品8"生长周期内对根际土壤中可培养真菌数和真菌群落结构的影响。结果显示, 相同生育期转基因水稻根际土壤可培养真菌数量与其非转基因对照水稻相比较无显著性差异, 表明转基因水稻的种植没有对根际土壤真菌数量产生明显影响; 18S rRNA真菌群落DGGE图谱分析显示, 相同生育期转基因水稻与其非转基因对照水稻的根际土壤真菌DGGE条带数量和条带位置均无显著性差异, 表明转基因水稻的种植没有对根际土壤真菌群落结构产生明显影响。进一步分析相同生育期转基因水稻与其非转基因对照水稻的根际土壤真菌群落香农多样性指数(Shannon diversity index)和均匀度指数(Evenness index)的动态变化, 发现两者均没有显著性差异。以上研究结果表明, 外源抗真菌基因的导入对水稻根际土壤中真菌群落数量和群落结构均没有明显影响。此外, 将不同位置的真菌DGGE条带切胶回收, 克隆、测序后, 进行系统进化树分析, 结果表明根际土壤真菌群落主要归属为子囊菌门(Ascomycota)、担子菌门(Basidiomycota)、壶菌门(Chytridiomycota)、接合菌门(Zygomycota)和未知真菌(unknown fungi)5个类群。

     

    Abstract: 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.

     

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