New strategy for isolating novel nematicidal crystal protein genes from Bacillus thuringiensis strain YBT-1518.

ABSTRACT: We have developed a strategy for isolating cry genes from Bacillus thuringiensis. The key steps are the construction of a DNA library in an acrystalliferous B. thuringiensis host strain and screening for the formation of crystal through optical microscopy observation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses. By this method, three cry genes--cry55Aa1, cry6Aa2, and cry5Ba2--were cloned from rice-shaped crystals, producing B. thuringiensis YBT-1518, which consists of 54- and 45-kDa crystal proteins. cry55Aa1 encoded a 45-kDa protein, cry6Aa2 encoded a 54-kDa protein, and cry5Ba2 remained cryptic in strain YBT-1518, as shown by SDS-PAGE or microscopic observation. Proteins encoded by these three genes are all toxic to the root knot nematode Meloidogyne

SUBMITTER: Guo S 

PROVIDER: S-EPMC2583473 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature