Genome-Wide Identification of the Remorin Gene Family in Poplar and Their Responses to Abiotic Stresses

The <i>Remorin</i> (<i>REM</i>) gene family is a plant-specific, oligomeric, filamentous family protein located on the cell membrane, which is important for plant growth and stress responses. In this study, a total of 22 <i>PtREMs</i> were identified in the genome of <i>Populus trichocarpa</i>. Subcellular localization analysis showed that they were predictively distributed in the cell membrane and nucleus. Only five PtREMs members contain both Remorin_C- and Remorin_N-conserved domains, and most of them only contain the Remorin_C domain. A total of 20 gene duplication pairs were found, all of which belonged to fragment duplication. Molecular evolutionary analysis showed the <i>PtREMs</i> have undergone purified selection. Lots of <i>cis</i>-acting elements assigned into categories of plant growth and development, stress response, hormone response and light response were detected in the promoters of <i>PtREMs</i>. <i>PtREMs</i> showed distinct gene expression patterns in response to diverse stress conditions where the mRNA levels of <i>PtREM4.1</i>, <i>PtREM4.2</i> and <i>PtREM6.11</i> were induced in most cases. A co-expression network centered by <i>PtREMs</i> was constructed to uncover the possible functions of <i>PtREMs</i> in protein modification, microtube-based movement and hormone signaling. The obtained results shed new light on understanding the roles of <i>PtREMs</i> in coping with environmental stresses in poplar species.