The expression of mitogen-activated protein kinase(mapk) double-stranded RNA in cucumber is effective in controlling infestations of the root-knot nematode Meloidogyne incognita. However,little is known about the ecological effects of transgenic plants. Here,we analyzed the diversity of 16 S r DNA genes derived from the rhizosphere archaea of transgenic cucumber plants as an indicator of ecological change. A total of 17 and 18 operational taxonomic units were detected in the rhizospheres of non-transgenic cucumber and mapk ds RNA-expressing plants,respectively. No significant difference was observed between the two groups according to Shannon and Simpson indices. In soil samples of the two rhizospheres,the dominant group was Crenarchaeota at the phylum level,with Staphylothermus,Methanococcus,Pyrodictium and Sulfolobus the abundant taxa at the genus level. These results suggest that expressing mapk double-stranded(ds) RNA in cucumber has no apparent effect on the diversity of rhizosphere archaea,and provide powerful evidence for the ecological safety of transgenic cucumber expressing mapk ds RNA.
