[The plasmid harboring cry26Aa may contribute to the phenomenon of spore-crystal connection in Bacillus thuringiensis subsp. finitimus].

Parasporal crystal in B. thuringiensis subsp. finitimus T02 forms inside the exosporium and remains attached to the spore after mother cell lysis. Two crystal protein gene cry26Aa and cry28Aa were cloned from this strain. The relationship between the phenomenon of spore-crystal connection and the plasmids was investigated in this work. Mutants BMB1151 curing of the plasmid harboring cry26Aa, and BMB1152 curing of all plasmids were obtained from B. thuringiensis subsp. finitimus T02.The spore-crystal connection didn't appeared when cry26Aa and cry28Aa were transformed back into the strain BMB1152 by shuffle vector alone or in combination together. It suggested the plasmids of B. thuringiensis subsp. finitimus TD2 may contribute to the phenomenon. When gene cry26Aa was transformed back into in the strain BMB1151, spore-crystal connection didn't form either. So the plasmid harboring cry26Aa may also contribute to the phenomenon of spore-crystal connection in B. thuringiensis subsp. finitimus T02.