Discrimination of Japanese isolates of Beauveria brongniartii (Deuteromycotina: Hyphomycetes) by RFLP of the rDNA-ITS regions

Abstract

Isolates of the entomopathogenic fungus Beauveria brongniartii differ in the shape of the conidia and the amount of red pigment production, which are associated with the host insects they were obtained from. We investigated intraspecific polymorphisms among 38 isolates of B. brongniartii by using restriction fragment length polymorphisms (RFLP) of the internal transcribed spacer regions (ITS1 and ITS2), 5.8S rDNA, and small portions of the 18S and 28S rDNAs. Based on the RFLP patterns, the isolates were divided into two distinct groups. One group was composed mainly of isolates from longicorn beetles (Coleoptera: Cerambycidae), whereas the other group mainly contained isolates from scarab beetles (Coleoptera: Scarabaeidae). The DNA sequences of the amplified regions showed high homology between the groups, with only 7 substitutions in 852 nucleotides, and just 1 of the 7 substitutions accounted for the difference in the RFLP patterns between the two groups. Furthermore, RFLP successfully distinguished all of the B. brongniartii isolates from the 5 tested isolates of B. bassiana and the 1 of B. amorpha.