Biological influence of cry1Ab gene insertion on the endophytic bacteria community in transgenic rice

Abstract

The commercial release of genetically modified (GMO) rice for insect control in China is a subject of debate. Although aseries of studies have focused on the safety evaluation of the agroecosystem, the endophytes of transgenic rice are rarely considered.Here, the influence of endophyte populations and communities was investigated and compared for transgenic and nontransgenicrice. Population-level investigation suggested that cry1Ab gene insertion influenced to a varying degree the rice endophytes at theseedling stage, but a significant difference was only observed in leaves of Bt22 (Zhejiang22 transgenic rice) between the GMO andwild-type rice. Community-level analysis using the 16S rRNA gene showed that strains of the phyla Proteobacteria and Firmicutes werethe predominant groups occurring in the three transgenic rice plants and their corresponding parents. By contrast, the endophyticcommunities of Minghui63 and Xiushui11 showed a weaker response to cry1Ab gene insertion than did Zhejiang22, and the communityresults were consistent with the population-level investigation. The populations and communities of rice endophytes were affected bythe cry1Ab gene to a different extent in different rice varieties and plant tissues. The results of this study broaden our understanding ofunexpected transgenic influences on nontarget organisms.