Effects of planting isoproturon-resistant transgenic rice （Oryza sativa） and applying isoproturon on rhizospheric microbial communities of transgenic rice

【Objective】The effects of planting isoproturon-resistant transgenic rice and application of herbicide isoproturon on rhizospheric microbial communities of transgenic rice were studied to provide a scientific basis for ecological risk assessment of herbicide-resistant rice cultivation. 【Method】Based on pot experiments, the differences in rhizosphere microbial community diversity and composition between two isoproturon-resistant transgenic rice lines and their parents and isoproturon-treated transgenic rice at different rice growth stages were analyzed by high-throughput sequencing technique.【Result】The results of high-throughput sequencing showed that the dominant bacterial phyla in rhizospheric microbial communities at all growth stages of rice were Proteobacteria, Acidobacteriota, Gemmatimonadota, Bacteroidota, and Myxococcota. The dominant fungal phyla in the rhizosphere microorganisms were Rozellomycota, Ascomycota, Basidiomycota, Glomeromycota, and Mortierellomycota. Regardless of the cultivation of isoproturon-resistant transgenic rice, non-transgenic rice or the application of herbicide isoproturon, the richness index, Simpson diversity index, and Shannon diversity index of rice rhizosphere microbial communities were not significantly affected at the same growth stage of rice(P>0.05, the same below). There was no significant difference in the relative abundance of most dominant microbial phyla in the rhizosphere microorganisms of isoproturon-resistant transgenic rice, isoproturon-treated transgenic rice and non-transgenic rice. Individual dominant phyla changed at specific growth stages of rice. The cluster analysis based on the top 15 abundant microbial genera also showed that there were some differences in the composition of rhizospheric microbial communities among isoproturon-resistant transgenic rice, isoproturon-treated transgenic rice, and non-transgenic rice at some growth stages of rice. The principal component analysis of rhizosphere microbial communities showed that there was no significant difference in the composition of rhizospheric microbial communities among isoproturon-resistant transgenic rice, isoproturon-treated transgenic rice, and non-transgenic rice, but there were spatial differentiation at different growth stages in the composition of rhizosphere microbial communities. The results of variation partitioning analysis of rhizosphere microbial community showed that the influence of rice growth stage on bacterial community structure variations in rhizospheric soil was 45.62%, while the influences of varieties and application of isoproturon on bacterial community structure variations in rhizospheric soil were 1.15% and 2.76% respectively. The influence of rice growth stage on fungal community structure variations in rhizospheric soil was 48.36%, while the influence of varieties and application of isoproturon on fungal community structure variations in rhizospheric soil were only 1.36% and 2.45% respectively. 【Conclusion】The planting isoproturon-resistant transgenic rice and application of isoproturon causes no significant effect on rhizosphere microbial communities of transgenic rice. However, the bacterial and fungal communities in rhizosphere soils are influenced by the growth stages of rice to some extent.