%0 Journal Article
%T Detection of potentially valuable polymorphisms in four group I intron insertion sites at the 3'-end of the LSU rDNA genes in biocontrol isolates of Metarhizium anisopliae
%A Marcela M¨¢rquez
%A Enrique A Iturriaga
%A Enrique Quesada-Moraga
%A C¨¢ndido Santiago-¨¢lvarez
%A Enrique Monte
%A Rosa Hermosa
%J BMC Microbiology
%D 2006
%I BioMed Central
%R 10.1186/1471-2180-6-77
%X DNA fragments corresponding to the 3'-end of the nuclear LSU rDNA genes of 26 M. anisopliae isolates were amplified by PCR. The amplicon sizes ranged from 0.8 to 3.4-kb. Four intron insertion sites, according to Escherichia coli J01695 numbering, were detected- Ec1921, Ec2066, Ec2449 and Ec2563- after sequencing and analysis of the PCR products. The presence/absence of introns allowed the 26 isolates to be distributed into seven genotypes. Nine of the isolates tested showed no introns, 4 had only one, 3 two, and 10 displayed three introns. The most frequent insertion sites were Ec1921 and Ec2449. Of the 26 isolates, 11 showed insertions at Ec2563 and a 1754-bp sequence was observed in ten of them. The most-parsimonious (MP) tree obtained from parsimony analysis of the introns revealed a main set containing four-groups that corresponded to the four insertion sites.Four insertion sites of group I introns in the LSU rDNA genes allowed the establishment of seven genotypes among the twenty-six biocontrol isolates of M. anisopliae. Intron insertions at the Ec2563 site were observed for first time in this species.The use of entomopathogenic microorganisms to combat insects is currently considered to be a viable supplement or alternative to synthetic chemical insecticides, which are known to have toxic effects on non-target organisms [1]. Strains of Metarhizium have been shown to efficiently control several insect species [2,3]. The most common species is M. anisopliae, initially described as a pathogen of the wheat cockchafer Anisoplia austriaca. This fungus is commonly known as "green muscardine fungus" [4] and can infect the larvae and adults of more than 200 host species [5,3]. Once M. anisopliae spores have come into contact with the outer surface of the insect, they germinate. After penetrating the insect exoskeleton, they rapidly grow inside the insect and cause its death.Traditionally, the classification and typing of anamorphic entomopathogenic fungi have mainly be
%U http://www.biomedcentral.com/1471-2180/6/77