Slawinski Lucie, Israel Abir, Paillot Caroline, Thibault Florence, Cordaux Richard, Atanassova Rossitza, Dédaldéchamp Fabienne, Laloi Maryse
Laboratoire Ecologie et Biologie des Interactions, UMR Centre National de la Recherche Scientifique 7267, Université de Poitiers, Poitiers, France.
Front Plant Sci. 2021 Sep 6;12:681929. doi: 10.3389/fpls.2021.681929. eCollection 2021.
Carbon management by plants involves the activity of many sugar transporters, which play roles in sugar subcellular partitioning and reallocation at the whole organism scale. Among these transporters, the early response to dehydration six-like (ESL) monosaccharide transporters (MSTs) are still poorly characterized although they represent one of the largest sugar transporter subfamilies. In this study, we used an evolutionary genomic approach to infer the evolutionary history of this multigenic family. No ESL could be identified in the genomes of rhodophytes, chlorophytes, and the brown algae , whereas one ESL was identified in the genome of providing evidence for the early emergence of these transporters in Streptophytes. A phylogenetic analysis using the 519 putative ESL proteins identified in the genomes of 47 Embryophyta species and being representative of the plant kingdom has revealed that ESL protein sequences can be divided into three major groups. The first and second groups originated in the common ancestor of all spermaphytes [ζ: 340 million years ago (MYA)] and of angiosperms (ε: 170-235 MYA), respectively, and the third group originated before the divergence of rosids and asterids (γ/1R: 117 MYA). In some eudicots (Vitales, Malpighiales, Myrtales, Sapindales, Brassicales, Malvales, and Solanales), the ESL family presents remarkable expansions of gene copies associated with tandem duplications. The analysis of non-synonymous and synonymous substitutions for the dN/dS ratio of the copies of the genus has revealed that genes are evolved under a purifying selection even though the progressive increase of dN/dS ratios in the three groups suggests subdiversification phenomena. To further explore the possible acquisition of novel functions by ESL MSTs, we identified the gene structure and promoter -acting elements for genes. The expression profiling of unraveled some gene copies that are almost constitutively expressed, whereas other gene copies display organ-preferential expression patterns. This study provides an evolving framework to better understand the roles of ESL transporters in plant development and response to environmental constraints.
植物的碳管理涉及多种糖转运蛋白的活动，这些转运蛋白在糖的亚细胞分配以及整个生物体规模的重新分配中发挥作用。在这些转运蛋白中，早期脱水响应六类（ESL）单糖转运蛋白（MST）虽然是最大的糖转运蛋白亚家族之一，但其特征仍了解甚少。在本研究中，我们采用进化基因组学方法来推断这个多基因家族的进化历史。在红藻、绿藻和褐藻的基因组中未鉴定到ESL，而在链形植物基因组中鉴定到一个ESL，这为这些转运蛋白在链形植物中的早期出现提供了证据。使用在47种胚植物基因组中鉴定出的519个假定ESL蛋白进行的系统发育分析代表了植物界，结果表明ESL蛋白序列可分为三大类。第一组和第二组分别起源于所有种子植物的共同祖先[ζ：3.4亿年前（百万年前）]和被子植物（ε：1.7亿 - 2.35亿年前），第三组起源于蔷薇类植物和菊类植物分化之前（γ/1R：1.17亿年前）。在一些双子叶植物（葡萄目、金虎尾目、桃金娘目、无患子目、十字花目、锦葵目和茄目）中，ESL家族呈现出与串联重复相关的基因拷贝显著扩增。对番茄属基因拷贝的非同义替换与同义替换的dN/dS比率分析表明，尽管三组中dN/dS比率逐渐增加表明存在亚多样化现象，但番茄基因是在纯化选择下进化的。为了进一步探索ESL MST可能获得的新功能，我们鉴定了番茄基因的基因结构和启动子作用元件。番茄的表达谱分析揭示了一些几乎组成型表达的基因拷贝，而其他基因拷贝则显示出器官优先表达模式。本研究提供了一个不断发展的框架，以更好地理解ESL转运蛋白在植物发育和对环境限制的响应中的作用。
