Molecular investigation of two contrasting genotypes of Medicago truncatula to salt stress using two expressed sequence tag-simple sequence repeat (EST-SSRs) markers

Abstract

Two expressed sequence EST-SSRs primers were used to show genetic variation and determine a potential link of these markers to salt stress tolerance on two contrasting Medicago truncatula genotypes (Tru 131 tolerant genotype, and Jemalong, sensitive one). The amplification of the DNA were isolated from 10 individual seedlings for each genotype (tolerant and sensitive) with two Expressed Sequence Tag-Simple Sequence Repeat (EST-SSR) primers (MTIC 044) and (MTIC 124) produced a total of 20 amplified products, of which MTIC 124 was polymorphic. The sizes of the alleles detected ranged from 100 to 280 bp. The EST-SSRs markers were polymorphic with an average of 1.33 alleles per primers and gave moderate values of polymorphic information content (PIC) that ranged from 0 to 0.267. The analysis of polymorphism loci for each genotype showed that the tolerant genotype (Tru 131) population had two alleles; genetic diversity index of 0.32 and PIC value of 0.267. The results obtained from unigene database of highly similarity proteins sequences with these loci showed that these two EST- SSRs loci MTIC 044 and MTIC 124 encode GATA transcription factor and cysteine proteinase inhibitor, respectively and were expressed principally in root in M. truncatula. This data suggest that these two loci are involved in salt stress tolerance and the two EST-SSR markers used are appropriate for the studying of salt stress tolerance in M. truncatula.

Keywords: Medicago truncatula, salt stress, in silico analysis, expressed sequence tag-simple sequence repeat (EST-SSR), UniGene / UniProt databases.

African Journal of Biotechnology, Vol 13(41) 4046-4051