Specific activity of a Bacillus thuringiensis strain against Locusta migratoria manilensis.
Bacillus thuringiensis (Bt) has played an important role in biocontrol of pests. However, insecticidal activity of B. thuringiensis against locusts has been rarely reported. Bt strain BTH-13 exhibiting specific activity to locusts was isolated from a soil sample in China and characterized. Its bipyramidal parasporal crystal is mainly composed of a protein of 129kDa, and produces a mature toxin of 64kDa after activation. The pattern of total DNA from BTH-13 showed a large and three small plasmid bands. Known delta-endotoxin genes, cry1Aa, cry1Ab, cry1Ac, cry1C, cry3, cry4 and cry7Aa were not found from strain BTH-13 by PCR amplification. The sequence analysis of a DNA fragment produced by PCR amplification with degenerate cry-selective primers revealed that the fragment encoded a delta-endotoxin segment, which exhibited some similarity to several Cry proteins (41% of the highest similarity to Cry7Ba1). Toxicity tests were performed against Locusta migratoria manilensis, and the results demonstrated that trypsin-treated sporulated cultures and crystal proteins had high toxicity to larval and adult locusts. Cry toxin of BTH-13 was detected on the midguts of treated locusts using immunofluorescent technology, which confirmed the site of action of the crystal proteins in their toxicity for locusts.
Song
Lingli
L
Wuhan Institute of Virology, Chinese Academy of Sciences, Xiaohongshan 44, Wuhan City, Hubei Province 430071, PR China.
Gao
Meiying
M
Dai
Shunying
S
Wu
Yan
Y
Yi
Dan
D
Li
Rongsen
R
D000818:Animals; D001413:Bacillus thuringiensis / Q000145:classification / Q000502:physiology*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D017931:DNA Primers; D004269:DNA, Bacterial; D004591:Electrophoresis, Polyacrylamide Gel; D004731:Endotoxins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D005455:Fluorescent Antibody Technique; D006460:Hemolysin Proteins / Q000737:chemistry / Q000235:genetics; D048188:Locusta migratoria / Q000382:microbiology*; D010572:Pest Control, Biological; D016133:Polymerase Chain Reaction; D012988:Soil Microbiology
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis