Two delta-endotoxin genes, cry9Da and a novel related gene, commonly occurring in lepidoptera-specific Bacillus thuringiensis Japanese isolates that produce spherical parasporal inclusions
N. Wasano et al., Two delta-endotoxin genes, cry9Da and a novel related gene, commonly occurring in lepidoptera-specific Bacillus thuringiensis Japanese isolates that produce spherical parasporal inclusions, CURR MICROB, 42(2), 2001, pp. 129-133
Six Lepidoptera-specific Bacillus thuringiensis isolates, which belong to t
he four H serovars (sotto, fukuokaensis, canadensis, and galleriae) and pro
duce spherical parasporal inclusions, were examined for assignment of the c
lasses of the delta -endotoxin genes. Gene analysis was conducted by PCR te
chnique with primers designed to probe the genes cry9Ca and cry9Da. The dat
a revealed that the delta -endotoxin of a serovar canadensis isolate is enc
oded by the gene cry9Da, while those of the five other strains are encoded
by an undescribed delta -endotoxin gene. DNA fragments from five strains ha
d an identical 1917-bp nucleotide sequence, covering the four conserved reg
ions and a partial sequence of the block 5 region. The deduced amino acid s
equence exhibited a 70.6% homology to that of the corresponding region of t
he Cry9Ea delta -endotoxin protein which is active on the order Lepidoptera
, and a 63.1% homology to the Cry9Ca protein highly toxic to the noctuid le
pidopterans. The results showed that Japanese isolates of B. thuringiensis
producing spherical parasporal inclusions with Lepidoptera-specific activit
y are categorized into two groups: one produces the class Cry9Da protein an
d the other a novel delta -endotoxin allied to the class Cry9. It also appe
ared that heterogeneous multiple H serovars are involved in each group.