Screening for novel cry genes by hybridization

Aims: To develop an efficient and sensitive method to facilitate the search for novel Cry toxins. Methods and Results: The method uses a cocktail of cry gene sequences as a hybridization probe to screen Bacillus thuringiensis (Bt) strains and gene libraries prepared from them. Under the hybridization and washing condition s used, cross-hybridization between genes from different cry families was n ot observed. Probes containing either partial or complete cry gene sequence s produced similar patterns when hybridized to genomic DNA of several Bt st rains although the pattern produced by the probe composed of entire gene co ding regions was somewhat more complex. Conclusions: As a toot for gene library screening, hybridization with a mix ture of cry gene sequences is an efficient means of detecting clones contai ning a diverse range of cry genes in a single step. Significance and Impact of the Study: This technique greatly improves the e ase and efficiency of novel toxin gene discovery compared to previous metho ds.