Genomic–proteomic analysis of a novel Bacillus thuringiensis strain: toxicity against two lepidopteran pests, abundance of Cry1Ac5 toxin, and presence of InhA1 virulence factor

• Published in: Archives of microbiology Vol. 205; no. 4; p. 143
• Main Authors: Alves, Giselly Batista, de Oliveira, Eugênio Eduardo, Jumbo, Luis Oswaldo Viteri, dos Santos, Gil Rodrigues, dos Santos, Manoel Mota, Ootani, Marcio Akio, Ribeiro, Bergmann Morais, Aguiar, Raimundo Wagner de Souza
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-04-2023; Springer Nature B.V
• Subjects: Agrochemicals; Animals; Bacillus thuringiensis; Bacillus thuringiensis - chemistry; Bacillus thuringiensis - genetics; Bacterial Proteins - genetics; Bacterial Proteins - toxicity; Bioassays; Biochemistry; Biological control; Biomedical and Life Sciences; Biotechnology; Cell Biology; DNA topoisomerase; Ecology; Endotoxins - genetics; Endotoxins - toxicity; Enterotoxins; Genes; Genomic analysis; Genomics; Hemolysin Proteins - genetics; Hemolysin Proteins - toxicity; Hemolysins; Insecta; Insecticide resistance; Insecticides; Insects; Larva; Larvae; Life Sciences; Microbial Ecology; Microbiology; Mixtures; Moths; Original Paper; Pathogenicity; Pathogens; Pest control; Pest Control, Biological - methods; Pest resistance; Pesticides; Pests; Phylogeny; Proteins; Proteomics; Soybeans; Sugarcane; Toxicity; Toxins; Virulence; Virulence factors; Virulence Factors - genetics; Lepidopteran pest; Biopesticide; Genome sequence; Toxicity; Cry proteins; Proteomic; Bacillus thuringiensis
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s00203-023-03479-y

Bacillus thuringiensis
(
Bt
) is a biological alternative to the indiscriminate use of chemical insecticides in agriculture. Due to resistance development on insect pests to
Bt
crops, isolating novel
Bt
strains is a strategy for screening new pesticidal proteins or strains containing toxin profile variety that can delay resistance. Besides, the combined genomic and proteomic approaches allow identifying pesticidal proteins and virulence factors accurately. Here, the genome of a novel
Bt
strain (
Bt
TOL651) was sequenced, and the proteins from the spore–crystal mixture were identified by proteomic analysis. Toxicity bioassays with the spore–crystal mixture against larvae of
Diatraea saccharalis
and
Anticarsia gemmatalis
, key pests of sugarcane and soybean, respectively, were performed. The toxicity of
Bt
TOL651 varies with the insect;
A. gemmatalis
(LC
50
 = 1.45 ng cm
−2
) is more susceptible than
D. saccharalis
(LC
50
 = 73.77 ng cm
−2
). Phylogenetic analysis of the
gyrB
gene indicates that TOL651 is related to
Bt kenyae
strains. The genomic analysis revealed the presence of
cry1Aa18
,
cry1Ac5
,
cry1Ia44
, and
cry2Aa9
pesticidal genes. Virulence factor genes such as phospholipases (
plcA
,
piplc
), metalloproteases (
inhA
), hemolysins (
cytK
,
hlyIII
,
hblA
,
hblC
,
hblD
), and enterotoxins (
nheA
,
nheB
,
nheC
) were also identified. The combined use of the genomic and proteomic data indicated the expression of Cry1Aa18, Cry1Ac5, and Cry2Aa9 proteins, with Cry1Ac5 being the most abundant. InhA1 also was expressed and may contribute to
Bt
TOL651 pathogenicity. These results provide
Bt
TOL651 as a new tool for the biocontrol of lepidopteran pests.