ABSTRACT
Almost all active plant retroelements are known to be induced by various biotic and abiotic stresses. Here, we show the presence of transcriptionally active Ty1-copia like retroelements in chickpea and their induction in response to abiotic stress. Eight Ty1-copia retrotransposon like mRNA sequences were reverse transcribed, amplified, cloned and characterized from stressed plants. These mRNA sequences were not detected in chickpea plants grown under normal conditions. Basing on the similarity analysis, these RT transcript sequences were classified into three families. It is proposed that all sequences except CARE7 might be transcript sequences of functional retrotransposons. The mRNA sequence CARE3 shows 99% nucleotide identity to a genomic Ty1-copia like sequence present in the Genbank with accession no. AJ535883.
Subject(s)
Cicer/genetics , Phylogeny , RNA, Messenger/genetics , RNA, Plant/genetics , Retroelements/genetics , Stress, Physiological/genetics , Base Sequence , Cicer/metabolism , Molecular Sequence Data , RNA, Messenger/biosynthesis , RNA, Plant/biosynthesisABSTRACT
Retrotransposons represent a major fraction of the plant genome and play a significant role in the molecular evolution through sequence re-organization. In order to access the diversity in Ty1-copia group of retrotransposons in chickpea, reverse transcriptase (RT) conserved domain specific primers were selected to amplify RT conserved sequences. Thirty-six amplified fragments were cloned and characterized. On the basis of deduced amino acid homology among them, these sequences were grouped into five families. These sequence families showed from 34 to 81% inter-family homology at the amino acid level. Although these sequences belong to a highly conserved region no two sequences were identical. The results show that there is a high degree of heterogeneity among the Ty1-copia group of retroelements in chickpea. The genomic Southern hybridization with one of the reverse transcriptase sequences as a probe shows the presence of a large population of the Ty1-copia group of retrotransposons in chickpea.
