Genome profiling implies high genetic diversity in microsporidia isolated from the common cutworm, Spodoptera litura (Lepidoptera: Noctuidae), in Vietnam

Abstract

In order to evaluate the potential application of microsporidia as a microbial control agent against lepidopteran insect pests, microsporidian infection in a field population of the common cutworm, Spodoptera litura (Fabricius), was surveyed in vegetable crop fields in Can Tho City, Vietnam, in March 2007. The infection rate of microsporidia was 46.7% (99/212 individuals) in adult S. litura, and 16 samples of infected adults were used to characterize the microsporidia at the molecular level. Analysis of the small subunit ribosomal RNA (SSU rRNA) sequences indicated that microsporidian strains isolated from S. litura were closely related to Nosema bombycis from the silkworm, Bombyx mori (Linnaeus); however, phylogenetic analysis based on genome profiling produced a different result from the SSU rRNA sequences. Temperature gradient gel electrophoresis profiles of 12 microsporidian strains from S. litura were closely related to N. bombycis strains, while the profiles of three microsporidian strains formed a different cluster. The Vietnamese strains did not form a single group, but were classified into at least three groups. These results suggested that the microsporidia isolated from S. litura in the Mekong Delta, Vietnam, are genetically diverse.

Phylogenetic relationships among Bacillus thuringiensis (Bacillaceae: Bacillales) strains based on a comparison of SSU rRNA sequences and genome profiling

“…On the other hand, GP is a method that allows for simple comparisons of entire genomes, and it might therefore produce results that better reflect the evolutionary relationships between organisms. Hatakeyama et al (2011) successfully used GP to conduct a phylogenetic analysis of entomogenous microsporidia. They were able to classify microsporidia strains that were previously found to belong to a single strain (based on SSU rRNA sequence analyses) into multiple clusters.…”

“…To do this, we used a traditional method, SSU rRNA sequence analysis, and a novel method, genome profiling (GP). GP (Nishigaki et al 1991;Hamano et al 1996) has been used to assess the phylogenetic relationships among alkaline thermophilic bacteria (Yamamoto et al 2006) and entomogenous microsporidia (Hatakeyama et al 2011). GP is used to compare whole genomes rather than individual sequences, and it is a useful method for elucidating the phylogenetic relationships among closely related organisms.…”