Rajchanuwong Prakai, Peaboon Sawaporn, Ngoen-Klan Ratchadawan, Rattanawannee Atsalek, Noosidum Atirat, Promdonkoy Boonhiang, Chanpaisaeng Jariya, Chareonviriyaphap Theeraphap
Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, 10900, Thailand.
Research and Lifelong Learning Center on Urban and Medical Entomology, Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, 10900, Thailand.
Curr Res Parasitol Vector Borne Dis. 2025 Jan 27;7:100245. doi: 10.1016/j.crpvbd.2025.100245. eCollection 2025.
Organophosphates, carbamates and synthetic pyrethroids are commonly used in Thailand to control mosquito vectors; however, long-term use of insecticides in vector control has led to the rapid development of insecticide resistance. In this study, we screened strains as biological control agents for potential toxins against mosquito larvae as an additional control tool. Preliminary bioassays conducted on 434 strains demonstrated that 41 strains (11.64%) and 14 strains (3.97%) achieved 100% mortality against and larvae, respectively. Three strains (JC690, JC691, and JC699) showed toxicity to both mosquito species, compared with the reference Bti strain. Strain JC691 demonstrated the highest efficacy against and , with an LC value of 6.96 × 10 CFU/ml and 1.16 × 10 CFU/ml, respectively. A comparison of LC values revealed that JC691 exhibited higher efficacy against than that by Bti (Bti LC: 8.89 × 10⁴ CFU/ml) but lower efficacy against (Bti LC: 1.99 × 10³ CFU/ml). Scanning electron microscopy revealed that JC690, JC691, and JC699 are rod-shaped, have oval spores, and produce bi-pyramidal crystal proteins. Protein profile analysis using SDS-PAGE demonstrated distinct differences between these Thailand strains (JC690, JC691, and JC699) and the reference Bti strain. All three Thailand strains contained 1I and 2A genes, and only JC691 harbored the 32 gene. Bayesian inference and maximum likelihood phylogenetic analyses of 32 indicated that the partial sequences of 32 in JC691 from Thailand were distinct from those of other strains from different countries. This study demonstrates the potential of JC690, JC691, and JC699 as biocontrol agents for and .
有机磷酸酯、氨基甲酸酯和拟除虫菊酯类化合物在泰国常用于控制蚊媒；然而，在病媒控制中长期使用杀虫剂已导致杀虫剂抗性迅速发展。在本研究中，我们筛选菌株作为生物防治剂，寻找对蚊幼虫有潜在毒性的毒素，作为一种额外的防治工具。对434株菌株进行的初步生物测定表明，分别有41株（11.64%）和14株（3.97%）对致倦库蚊和白纹伊蚊幼虫的死亡率达到100%。与参考苏云金芽孢杆菌以色列亚种菌株相比，三株菌株（JC690、JC691和JC699）对两种蚊虫均表现出毒性。菌株JC691对致倦库蚊和白纹伊蚊的防治效果最佳，其LC值分别为6.96×10⁶CFU/ml和1.16×10⁶CFU/ml。LC值比较显示，JC691对致倦库蚊的防治效果高于苏云金芽孢杆菌以色列亚种（苏云金芽孢杆菌以色列亚种LC：8.89×10⁴CFU/ml），但对白纹伊蚊的防治效果低于苏云金芽孢杆菌以色列亚种（苏云金芽孢杆菌以色列亚种LC：1.99×10³CFU/ml）。扫描电子显微镜显示，JC690、JC691和JC699呈杆状，有椭圆形孢子，并产生双锥形晶体蛋白。使用SDS-PAGE进行的蛋白质谱分析表明，这些泰国菌株（JC690、JC691和JC699）与参考苏云金芽孢杆菌以色列亚种菌株之间存在明显差异。所有三株泰国菌株都含有1I和2A基因，只有JC691含有32基因。对32基因的贝叶斯推断和最大似然系统发育分析表明，泰国JC691中32基因的部分序列与来自不同国家的其他苏云金芽孢杆菌以色列亚种菌株不同。本研究证明了JC690、JC691和JC699作为致倦库蚊和白纹伊蚊生物防治剂的潜力。
