A gene encoding a protein with a proline-rich domain (MtPPRD1), revealed by suppressive subtractive hybridization (SSH), is specifically expressed in the Medicago truncatula embryo axis during germination

Abstract

A gene MtPPRD1, encoding a protein of 132 amino acids containing a proline-rich domain (PRD), has been revealed by suppressive subtractive hybridization (SSH) with two mRNA populations of embryo axes harvested immediately before and after radicle emergence. Although at the protein level MtPPRD1 showed low homology with plant lipid transfer proteins (LTPs), it did exhibit the eight cysteine residues conserved in all plant LTPs, a characteristic signature that allows the formation of a hydrophobic cavity adapted for loading hydrophobic molecules. Expression studies of MtPPRD1 have been carried out by quantitative real time RT-PCR throughout germination and post-germination processes in control seeds and seeds in which germination was delayed by abscisic acid (ABA) or the glutamine synthetase inhibitor methionine sulphoximine (MSX) treatments. The results showed that MtPPRD1 expression is developmentally regulated, induced in the embryo axis immediately before radicle emergence, reaches its maximum expression and declines during the early post-germination phase. Organ specificity studies showed that, except for a low and probably constitutive expression in roots, MtPPRD1 is specifically expressed in the embryo axis. Based on both experimental and in silico studies several putative roles are proposed for MtPPRD1 in Medicago truncatula, this protein can intervene (i) as an LTP in membrane biogenesis and regulation of the intracellular fatty acid pool by binding and transferring fatty acids and phospholipids between membranes, (ii) in the control of a developmental process specific to late germination and to early phases of post-germination, and (iii) and/or pathogen defence.

A Novel Type of Thioredoxin Dedicated to Symbiosis in Legumes

“…, using mean values obtained with two constitutive genes, Msc27 and 18S RNA (Montrichard et al, 2003;Bouton et al, 2005). As expected Trx s1 and Trx s2 were found to be highly expressed in nodules, transcripts of Trx s1 being notably very abundant in these organs (Fig.…”

The HyPRP gene EARLI1 has an auxiliary role for germinability and early seedling development under low temperature and salt stress conditions in Arabidopsis thaliana

“…In this paper we present evidence that EARLI1 plays an additional positive role in low-temperature and high salinity germinability of Arabidopsis seeds and root and shoot development under high salinity stress conditions, and a negative effect on germinability in the presence of high concentrations of exogenously applied ABA. EARLI1 may thus have similar functions as EARLI1-like genes previously implicated to have positive roles in the germination process of both monocots and dicots (Bouton et al 2005;Fujino et al 2008;Gimeno-Gilles et al 2009;Hori et al 2010).…”

<italic>GhHyPRP4</italic>, a cotton gene encoding putative hybrid proline-rich protein, is preferentially expressed in leaves and involved in plant response to cold stress

“…The expression of the strawberry Fahyprp gene is fruit specific and varies through the different fruit development and ripening stages [7]. MtPRPD1 is specifically expressed in the embryo axis during radicle emergence and early postgermination [23]. ZmHyPRP gene is found to be transcribed in immature maize embryos and ovary prior to pollination [5].…”