[Co-expression of crystal protein gene cry26Aa and cry28Aa has an ability to form parasporal crystal inside exosporium in Bacillus thuringiensis subsp. finitimus]

Abstract

Parasporal crystal in Bacillus thuringiensis subsp. finitimus T02 forms within the exosporium and remains attached to the spore after mother cell lysis, which leads to spore-crystal connection. According to the crystal protein gene sequence in B. thuringiensis subsp. finitimus, cry26 and cry28 were cloned from strain T02 by PCR amplification and transformed into the crystal negative Bacillus thuringiensis strain BMB171 by shuttle vectors, alone or in combination together. Crystal can be observed inside of exosporium when co-expression of these two genes. But crystal mainly formed outside of exosporium when they expressed alone. This suggests interaction between of the two crystal proteins may be involved in enclosure.