Isolation,Genetic Transformation And Colonization Capacity Analysis Of Symbiotic Gut Bacteria In The Rice Water Weevil,Lissorhoptrus Oryzophilus Kuschel

Symbiotic bacteria play important roles in a number of biological processes of insect hosts including growth, development, reproduction, resistance to pathogens and harmful substances. The rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera, Curculionidae), is an important invasive pest in China. This weevil can result in serious damage on rice yield in this country. It spreads fast and is difficult to control. Previous studies show that the diversity of symbiotic gut bacteria in this weevil is low, and Pantoea and Wolbachia are dominant species. In this study, based on the amplification and analysis of bacterial 16S rRNA gene sequences, bacterial species were identified from adult guts of different geographic weevil populations, and the bacteria were transformed with plasmid vector, pZeoDsRed. The colonization capacity of the transformed bacteria was also observed in the guts. The results are summarized below:Two bacteria, Bacillus cereus and Enterobacter ludwigii, were identified from adult guts of rice water weevils collected from three geographic locations, i.e., Yuanping of Shanxi, Xundian of Yunnan and Xiangxiang of Hunan. B. cereus has been reported in several other insects, and it is the first time to be identified in rice water weevil. E. ludwigii, to our best knowledge, has never been previously reported in insects.B. cereus and E. ludwigii, as well as one bacterium together Enterococcus faecalis which was identified in a previous study from guts of the weevil, were genetically transformed with plasmid vector, pZeoDsRed. Recombinant bacteria of each of these three species were obtained which can resist Ampicillin and Zeocin. The result shows that some bacterial species of rice water weevil gut can be transformed with the value of further research.The transformed bacteria were successfully reintroduced into rice water weevil adults and all the three species survived in the gut for at least 7 days. Each of these species bacteria increased quantitatively at first after treatments and then decreased after 48 h.The results are expected to lay a base for our future studies on the biological of these bacteria, their interactions with the other bacteria in the weevil, and on their potentials being used as paratransgenesis-based biological control candidates for rice water weevil...