PCR amplification and sequence analyses of reverse transcriptase-like genes in Crinipellis perniciosa isolates

Abstract

Reverse transcriptase (RT) sequence analysis is an important technique used to detect the presence of transposable elements in a genome. Putative RT sequences were analyzed in the genome of the pathogenic fungus C. perniciosa, the causal agent of witches' broom disease of cocoa. A 394 bp fragment was amplified from genomic DNA of different isolates of C. perniciosa belonging to C-, L-, and S-biotypes and collected from various geographical areas. The cleavage of PCR products with restriction enzymes and the sequencing of various RT fragments indicated the presence of several sequences showing transition events (G:C to A:T). Southern blot analysis revealed high copy numbers of RT signals, forming different patterns among C-, S-, and L-biotype isolates. Sequence comparisons of the predicted RT peptide indicate a close relationship with the RT protein from thegypsy family of LTR-retrotransposons. The possible role of these retrotransposons in generating genetic variability in the homothallic C. perniciosa is discussed.

The distribution of a transposase sequence in Moniliophthora perniciosa confirms the occurrence of two genotypes in Bahia, Brazil

“…According to Andebrhan et al (1999), the geographic distribution of the genetic groups in Bahia and the fact that M. perniciosa C-biotype is homothallic suggest the existence of two independent points of introduction of this pathogen into the cocoa-growing region of Bahia. Pereira et al (2007) showed two different distribution profiles of a RT-like (reverse transcription) sequence in isolates from C-biotype collected in the Bahia. In conclusion, these studies correlate the occurrence of these two genotypes with two independent introductions of Witches' broom disease in the southern region of the Bahia state.…”