Exploration of insecticidal genes in Bt S2480-1:based on the analysis of genome and proteome

Abstract:

[Objective]To identify the insecticidal activity of wild-type Bacillus thuringiensis strain Bt S2480-1 and explore the insecticidal gene resources.[Methods]The whole genome of Bt S2480-1 was sequenced by Illumina Hiseq2000.The genome information,genes,and insecticidal genes of the strain were analyzed with bioinformatics methods.The total proteins of Bt S2480-1 were analyzed by LTQ-Obitrap nano-LC-MS/MS and the biological activity of Bt S2480-1 against Culex quinquefasciatus and Spodoptera exigua larvae was determined.[Results]The genome of Bt S2480-1 was 6.2 Mb,with GC content of 35.11%,and one nucleoid and three large plasmids were yielded through assembly,containing 6 297 coding genes with 12 encoding insecticidal proteins.Meanwhile,a total of 1 500 proteins of Bt S2480-1 were identified by LTQ-Orbitrap MS/MS,among which 11 were insecticidal proteins.The total proteins of Bt S2480-1 showed strong activity against C.quinquefasciatus larvae but relatively weak activity against S. exigua larvae,with LC₅₀ of 27.636 μg/mL (95% FL:12.559-61.707 μg/mL) and 496.833 μg/mg (95% FL:320.134-776.964 μg/mg),respectively.[Conclusion] Bt S2480-1 contains 12 genes encoding insecticidal proteins and displays insecticidal activity against C. quinquefasciatus and S.exigua larvae.