Structure and vascular tissue expression of duplicated TERMINAL EAR1-like paralogues in poplar

Abstract

TERMINAL EAR1-like (TEL) genes encode putative RNA-binding proteins only found in land plants. Previous studies suggested that they may regulate tissue and organ initiation in Poaceae. Two TEL genes were identified in both Populus trichocarpa and the hybrid aspen Populus tremula x P. alba, named, respectively, PoptrTEL1-2 and PtaTEL1-2. The analysis of the organisation around the PoptrTEL genes in the P. trichocarpa genome and the estimation of the synonymous substitution rate for PtaTEL1-2 genes indicate that the paralogous link between these two Populus TEL genes probably results from the Salicoid large-scale gene-duplication event. Phylogenetic analyses confirmed their orthology link with the other TEL genes. The expression pattern of both PtaTEL genes appeared to be restricted to the mother cells of the plant body: leaf founder cells, leaf primordia, axillary buds and root differentiating tissues, as well as to mother cells of vascular tissues. Most interestingly, PtaTEL1-2 transcripts were found in differentiating cells of secondary xylem and phloem, but probably not in the cambium itself. Taken together, these results indicate specific expression of the TEL genes in differentiating cells controlling tissue and organ development in Populus (and other Angiosperm species).

The function of the RNA-binding protein TEL1 in moss reveals ancient regulatory mechanisms of shoot development

“…However, as TEL genes appear to regulate leaf-like organ initiation and development both in P. patens and vascular plants (this work; Veit et al 1998;Kawakatsu et al 2006;Xiong et al 2006), two possibilities emerge: (1) either TEL genes were independently recruited twice for leaf formation, to assume the same function, in bryophytes and vascular plants; or (2) TEL genes were already present in the bryophytes and vascular plants ancestors, suggesting a more basic function in plant development. The fact that TEL genes are not only expressed in leaves but also in differentiating tissues of stems, vascular cells and rhizoids in P. patens, or, on the other hand, vascular tissues, axillary buds and root meristems in vascular plants (Paquet et al 2005;Charon et al 2010) strengthens this last hypothesis. Our detailed expression analysis revealed the presence of PpTEL1 transcripts in young developing leaves-but not in the youngest ones-of P. patens (Figs.…”

“…2, 3). In vascular plants, TEL expression was found in leaf primordia, as soon as leaf founder cells exit from the shoot apical meristem (Paquet et al 2005;Charon et al 2010). As moss PpTEL1 and angiosperm TEL genes seem to have a conserved function in the regulation of leaf initiation and development at macroscopic level, they might be expected to share similar expression patterns.…”

Non-Protein-Coding RNAs and their Interacting RNA-Binding Proteins in the Plant Cell Nucleus

“…In monocots, TEL genes were shown to regulate leaf initiation and development, as well as flowering transition and inflorescence development (Veit et al, 1998;Kawakatsu et al, 2006;Xiong et al, 2006), whereas the other mei2-like genes, like the AMLs (Arabidopsis mei2-like) in A. thaliana, mainly seem to play a role in meiosis like mei2 in fission yeast (Hirayama et al, 1997;Kaur et al, 2006). Expression analysis confirmed a conserved association of TEL expression with tissue and organ initiation (Paquet et al, 2005;Charon et al, 2010), suggesting a putative role for TEL RBPs in the cellular mitosisdifferentiation transition. Sme2-like npcRNAs appear not to exist in plants (C. Charon, unpublished data) and plant RNA Mei2p-like RBP partners still remain unknown.…”

“…Formation of this dot coincides with the onset of mei-osis I and Mei2p may antagonize selective elimination of meiotic messenger RNAs by sequestering another RBP, Mmi1p, in this nuclear dot structure (Harigaya et al, 2006;Harigaya and Yamamoto, 2007). Whereas one unique mei2 gene is present in S. pombe and does not exist in S. cerevisiae, the mei2-like family has undergone a great expansion in the vascular plant lineage (Anderson et al, 2004;Charon et al, 2010;Jeffares et al, 2004). All these plant mei2-like genes encode RBPs with three RRMs, particularly the third distinctive C-terminal RRM that is essential for Mei2p function and only present in the Mei2p-like proteins.…”

Proteomics Revealed Distinct Responses to Salinity between the Halophytes Suaeda maritima (L.) Dumort and Salicornia brachiata (Roxb)

“…In S. brachiata the protein expansin-B1 was down-accumulated at both salt treatments, while the leucine-rich repeat receptor-like kinase protein, a protein promoting vegetative meristem, was down-accumulated. However, the protein terminal ear1 (regulating leaf initiation rate and shoot development) [31] was up-accumulated at 200 mM NaCl pointing out an opposite trend at the highest concentrations (Table 1).…”