Division of Plant and Soil Sciences, West Virginia University, 3425 New Agricultural Sciences Building, Morgantown, WV, 26506-6108, USA.
Plant Molecular Physiology Laboratory, Biology Department, Federal University of Lavras (UFLA), Lavras, MG, Brazil.
BMC Plant Biol. 2017 Oct 30;17(1):185. doi: 10.1186/s12870-017-1115-2.
Species in the Solanaceae family are known for producing plethora of specialized metabolites. In addition to biosynthesis pathways, a full comprehension of secondary metabolism must also take into account the transport and subcellular compartmentalization of substances. Here, we examined the MATE (Multidrug and Toxic Compound Extrusion, or Multi-Antimicrobial Extrusion) gene family in the tomato (Solanum lycopersicum) genome with the objective of better understanding the transport of secondary metabolites in this model species. MATE membrane effluxers encompass an ancient gene family of secondary transporters present in all kingdoms of life, but with a remarkable expansion in plants. They mediate the transport of primary and secondary metabolites using the proton motive force through several membrane systems of the cell.
We identified 67 genes coding for MATE transporters in the tomato genome, 33 of which are expressed constitutively whereas 34 are expressed in specific cell types or environmental conditions. Synteny analyses revealed bona fide paralogs and Arabidopsis orthologs. Co-expression analysis between MATE and regulatory genes revealed 78 positive and 8 negative strong associations (ρ≥|0.8|). We found no evidence of MATE transporters belonging to known metabolic gene clusters in tomato.
Altogether, our expression data, phylogenetic analyses, and synteny study provide strong evidence of functional homologies between MATE genes of tomato and Arabidopsis thaliana. Our co-expression study revealed potential transcriptional regulators of MATE genes that warrant further investigation. This work sets the stage for genome-wide functional analyses of MATE transporters in tomato and other Solanaceae species of economic relevance.
茄科植物以产生大量特殊代谢物而闻名。除了生物合成途径外，对次生代谢的全面理解还必须考虑物质的运输和亚细胞区隔化。在这里，我们研究了番茄（Solanum lycopersicum）基因组中的 MATE（多药和毒性化合物外排，或多抗菌外排）基因家族，目的是更好地了解该模式物种中次生代谢物的运输。MATE 膜外排泵包含一个古老的次级转运体基因家族，存在于所有生命领域，但在植物中显著扩张。它们利用质子动力通过细胞的几个膜系统来介导初级和次级代谢物的运输。
我们在番茄基因组中鉴定出 67 个编码 MATE 转运体的基因，其中 33 个基因组成型表达，而 34 个基因在特定细胞类型或环境条件下表达。同线性分析显示了真正的旁系同源物和拟南芥同源物。MATE 和调节基因之间的共表达分析显示了 78 个阳性和 8 个阴性强关联（ρ≥|0.8|）。我们没有发现属于已知代谢基因簇的 MATE 转运体存在于番茄中。
总之，我们的表达数据、系统发育分析和同线性研究为番茄和拟南芥 MATE 基因的功能同源性提供了强有力的证据。我们的共表达研究揭示了 MATE 基因的潜在转录调节因子，值得进一步研究。这项工作为番茄和其他经济相关茄科物种的 MATE 转运体的全基因组功能分析奠定了基础。
