ELSEVIER FEMS Microbiology Letters I34 ( 1995) 159- 164 Cloning of a novel crystal protein gene crylK from Bacillus thuringiensis ubsp. morrisoni

A novel crystal protein gene cryIK has been cloned and sequenced from a Bacillus thuringiensis subsp. morrisoni BF190 isolated from phylloplane. The upstream promoter region of crylK was almost identical with that of qlB. The deduced amino acid sequence of CrylK contains 1215 amino acid residues with an estimated molecular mass of 137.4 kDa. Comparison of the amino acid sequence of the Cry 1K with that of Cry proteins revealed that Cry IK is most closely related to CrylB and CrylI. Cry 1K has a high degree of identity with Cry 1B in the region between initiator codon and conserved sequence block 1, and with Cry IF in the region between conserved block 3 and 5. Protein inclusion purified from a recombinant strain of B. thuringiensis expressing the ctyIK gene was found to have a different insect-host specificity from CrylB, Cry 11 and Cry 1F. Cry 1K was found to be selectively toxic to Arfogeia rupae and not active to Plutella x_vlostellu