Heterogeneity in Ty1-copia group of retroelements in chickpea (Cicer arietinum) genome

Abstract

Retrotransposons constitute a major fraction of plant genomes and these elements may have played a significant role in evolution and sequence organization of genomes. In order to access the diversity of Ty1-copia group of retroelements, reverse transcriptase (RT) sequences were amplified from chickpea genome, using the primers derived from two conserved domains of RT region. Thirty-six RT regions from independent amplicons were cloned and sequenced. On the basis of homology of deduced amino acids, the RT sequences could be grouped into three major families. The intra-family divergence at amino acid level ranges from 2 to 19%. Though intra-family RT sequences were conserved but no two sequences were identical. The results indicate a high degree of heterogeneity among the Ty1-copia group of retroelements from chickpea. It was possible to isolate RT specific sequences from RNA isolated from stressed seedlings, indicating that some of the retroelements may be functional under certain stress conditions.