Expression analysis of salt stress related expressed sequence tags (ESTs) from Aeluropus littoralis by quantitative real-time PCR

Aeluropus littoralis is a monocot halophyte grass and provide valuable genetic resources for understanding the molecular mechanisms of stress-responsive genes, and improving tolerance to abiotic stresses in economically important crops. In an attempt to identify salt stressed responsive genes, 154 isolated expressed sequence tags (EST) from A. littoralis were bioinformatically analyzed and functionally annotated. Of the 129 assembled unique transcripts, 111 (86%) and 18 (14%) comprised of singletons and contigs, respectively. Among them, 58.9% could be assigned a putative identity, 20.9% with hypothetical or unknown functions and 20.9% showed no match with existing sequences. Expression pattern of 41 selected ESTs were estimated by quantitative realtime polymerase chain reaction (qPCR) in two different tissues. Expression profi ling were undertaken in control and three time point of salt stress (6hrs, 24hrs and one week) followed by three time point of recovery condition (6hrs, 24hrs and one week). In the root, the genes of SAMDC, ISB1 (6hrs), PP2C and SelO, HsfA1a, TFC D, Katanin, F-box were signifi cantly up-regulated relative to control while LecRLKs, ARP, HP3, PICKLE, Utp20, SYP81, CIPK20, HAK18, VDAC3, SND1, NAP1, ISB1 (6hrs and 24hrs), NUC2, MUT, HP1 and PIP1;3 showed down-regulation in given conditions. In the case of leaf tissue, the genes of PP2C, SelO, Utp20, SND1, PITP, LecRLKs, STPK, KCNK12, HsfA1a, HAK18, NUC2, ARP, HP3 and ARP were signifi cantly upor down-regulated. Differential regulation of these genes were observed in root and tissue which confi rm their role in salt stress tolerance. This functionally annotated EST and gene expression profi ling provide initial insights into the transcriptome of A. littoralis.