Kf. Chak et al., DETERMINATION AND DISTRIBUTION OF CRY-TYPE GENES OF BACILLUS-THURINGIENSIS ISOLATES FROM TAIWAN, Applied and environmental microbiology, 60(7), 1994, pp. 2415-2420
Using PCR with a set of specific oligonucleotide primers to detect cry
I-type genes, we were able to screen the cry-type genes of 225 Bacillu
s thuringiensis soil isolates from Taiwan without much cost in time or
labor. Some combinations of cry genes (the cry-type profile) in g sin
gle isolate were unique. We identified five distinct profiles of cryst
al genes from the B. thuringiensis soil isolates from Taiwan. The cry
genes included cryIA(a), cryIA(b), cryIA(c), cryIC, cryID, and cryIV.
Interestingly, 501 B. thuringiensis isolates (93.5% of the total numbe
r that we identified) were isolated from areas at high altitudes. The
profiles of cry-type genes were distinct in all isolation areas. The d
istribution of cry-type genes of our isolates therefore depended on ge
ography. Using PCR footprinting to detect cryIC-type genes, we identif
ied two distinct cryIC footprints from some of our isolates, indicatin
g that these isolates may contain novel cryIC-type genes. B. thuringie
nsis isolates containing cryIA(a)-, cryIA(b)-, and cryIA(c)-type genes
exhibited much greater activity against Plutella xylostella than did
other isolates, indicating that multiple cry type genes may be used as
markers for the prediction of insecticidal activities.