Bt S2160-1, a High Mosquitocidal Strain of <i>Bacillus thuringiensis</i>

Abstract

Bt strain S2160-1 was found to produce crystalline toxins with high insecticidal effects against mosquitoes ( Culex quinquefasciatus and Aedes albopictus ), which was characterized from the Bt isolate (Isolate No: 20070720S2160) from soil samples collected from Guangxi Dawangling Natural Reserves of Guangxi Province of China in 2007. Bt strain S2160-1 was stocked in the HITAR Bacillus Collections with Accession No 20070720S2160 and owned by HITAR. Scanning electron microscope observation showed that the spherical shape crystals of Bt S2160-1 with size at one fourth volume of spore to that of reference strain of Bti . SDS-PAGE analysis showed that the intact parasporal protein of Bt S2160-1 containing four major polypetide of about 140kDa, 130kDa, 75kDa and 30kDa was different from that of Bti . Furthermore, bioassays exhibited high toxicity to mosquito larva of Culex quinquefasciatus and Aedes albopictus . There are a great of differences in terms of the large plasmid patterns, parasporal proteins profiles and cry genes contents between Bt S2160-1 and Bti . The cloned genes of cry50Ba1 and cry54Ba1 expressed in BL21 (DE3) cells, but not success in Cry 30Ea1 and Cry 30Ga . Thus, it is believed that Bt S2160-1 could be applied into mosquito control as the potential alternative to prevent mosquito from developing the resistance to the toxins of Bti .