Cloning, expression and functional validation of drought inducible ascorbate peroxidase (Ec-apx1) from Eleusine coracana.
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| Abstract | :  Eleusine coracana (finger millet) is a stress-hardy but under-utilized cereal crop that possesses an efficient antioxidant defense system. The plant is capable of enduring long durations of water deficit stress. Experiments were conducted to clone a potent stress responsive isoform of ascorbate peroxidase and validate its role under drought stress. Reverse transcriptase PCR was used to obtain the partial cDNA of apx1 gene, from a meticulously screened drought tolerant genotype of E. coracana (PR202). Using RACE strategy, the full length apx1 cDNA was cloned and sequenced. The cDNA length of the E. coracana apx1 (Ec-apx1) gene is 1,047 bp with a 750 bp ORF, encoding a 250 amino acid protein having a molecular weight of 28.5 kDa. The identity of the amino acid sequence, deduced from the cDNA, with the APX family homologs was about 74-97 %. The full-length apx1 ORF was sub-cloned in a prokaryotic expression vector pET23b. The recombinant fusion protein, Ec-apx1, had high expression level in BL21 strain of E. coli and exhibited APX enzyme activity. The structure-function relationship of the protein was deduced by modelling a three-dimensional structure of Ec-apx1, on the basis of comparative homology using SWISS-MODEL. Real time PCR analysis of Ec-apx1 expression at mRNA level showed that the transcript increased under drought stress, with maximum levels attained 5-days after imposition of stress. Our results suggest that Ec-apx1 has a distinct pattern of expression and plays a pivotal role in drought stress tolerance. Therefore, the cloned isoform of ascorbate peroxidase can be used for developing stress tolerant genotypes of important crops, through transgenic approach. | 
| Year of Publication | :  2013 | 
| Journal | :  Molecular biology reports | 
| Volume | :  40 | 
| Issue | :  2 | 
| Number of Pages | :  1155-65 | 
| ISSN Number | :  0301-4851 | 
| URL | :  https://doi.org/10.1007/s11033-012-2157-z | 
| DOI | :  10.1007/s11033-012-2157-z | 
| Short Title | :  Mol Biol Rep | 
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