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.
BACKGROUND
The entomopathogenic anamorphic fungus Metarhizum anisopliae is currently used as a biocontrol agent (BCA) of insects. In the present work, we analyzed the sequence data obtained from group I introns in the large subunit (LSU) of rDNA genes with a view to determining the genetic diversity present in an autochthonous collection of twenty-six M. anisopliae isolates selected as BCAs.


RESULTS
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.


CONCLUSIONS
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.
Márquez
Marcela
M
Centro Hispano-Luso de Investigaciones Agrarias (CIALE), Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental lab 208, Plaza Doctores de la Reina s/n, 37007 Salamanca, Spain. mml@usal.es
Iturriaga
Enrique A
EA
Quesada-Moraga
Enrique
E
Santiago-Alvarez
Cándido
C
Monte
Enrique
E
Hermosa
Rosa
R
D020413:3' Untranslated Regions; D001483:Base Sequence; D017931:DNA Primers; D004271:DNA, Fungal / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics*; D005800:Genes, Fungal; D006999:Hypocreales / Q000235:genetics*; D007438:Introns; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic
D020413:3' Untranslated Regions; D017931:DNA Primers; D004271:DNA, Fungal; D004275:DNA, Ribosomal