Effects Of Transgenic Cucumber With Double Strands RNA Interference Expression Vector Of Mapk On Diversity Of Rhizospheric Soil Microorganisms

Cucumber is one of the important vegetable crops in China, but Meloidogyne spp. is the most important factor which affects the cucumber yield. The method of RNAi technology is low toxicity and economic, which is well on the way to becoming the more effective method to control Meloidogyne spp. The transgenic cucumber with mapk (Mitogen-activated protein kinase) dsRNA could inhibit expression of mapk gene of root knot nematode, and had good control efficiency to the nematode.Recently, more and more attention have been paid on the risk assessment of transgenic crops. Soil microorganisms have the advantages of large-number and high-sensitivity, which have become an important evaluation criterion of the safety of transgenic crops. In order to evaluate the ecological safety of this transgenic cucumber and to reveal the effect on the community of soil microorganisms, the diversity of soil bacteria, fungi, archaea and nematode in non-transgenic cucumber and transgenic cucumber were revealed by16s rRNA,18s rRNA,16s rRNA and18s rRNA gene clone library, respectively.Effects of transgenic cucumber on diversity of soil bacteria have been studied. From phylum level, genus level and the index of diversity, there was not markedly impact on soil bacteria by transgenic cucumber.The effects of transgenic cucumber on diversity of soil fungi have also been studied. It was indicated that the fungi in transgenic cucumber soil and non-transgenic cucumber soil were belonged to Ascomycota, Basidiomycota, Chytridiomycot, Fungi incertae sedis and Unclassified fungi, and Ascomycota fungi are dominant microflora. The diversity of fungi in non-transgenic cucumber soil was higher than that of transgenic cucumber soil. However, the percentage of dominant fungi group of non-transgenic cucumber soil was markedly lower than that of transgenic cucumber soil. Moreover, the fungus of Fusarium oxysporum with higher percentage in non-transgenic cucumber soil was not found from transgenic cucumber soil. These results reflected that transgenic cucumber with double strands RNA interference expression vector of mapk have some impacts on diversity of soil fungi, and some groups of fungi were inhibited by the transgenic cucumber.Through the research of the effect of transgenic cucumber on the community of rhizospheric soil archaea, it was found that the dominant archaea groups and the minority of archaea were same in two types of soil at phylum level and genus level. From the index of diversity, there was no differences in two types of soil. On the whole, the archaea communities of two types of soil were no differences, and not markedly been affected by transgenic cucumber.The diversity of soil nematode in non-transgenic cucumber and transgenic cucumber during the fruit period and harvest period were investigated. The results showed as follows:at genus level, the dominant archaea groups obtained from three libraries were Rhabdits, Cephalobus, Acrobelodies and Psilenchus. From the index of diversity, there were some differences on values of Simpson and Chao, but Shannon was similar. In general, some genera of soil nematode were affected by transgenic cucumber, which have different proportions in different libraries, but the effect was temporarily. After harvest, soil nematode at genus level restored its original level.