Genome-wide identification of the Remorin genes in Adiantum nelumboides and their responses to diverse abiotic stresses

Adiantum nelumboides is a traditional Chinese medical herb and an endangered fern, and its population is threatened by various abiotic stresses. The plant-specific Remorin (REM) genes play important roles in coping with abiotic stresses; however, the information about REMs in A. nelumboides is scarce. In this study, a total of 34 AnREMs were identified in the latest released genome of A. nelumboides. These AnREMs could be assigned into three groups with 16 genes in Group 1, 3 genes in Group 4 and 15 genes in Group 6. All the REM proteins contained the conserved Remorin_C domain, while only AnREM1.2e harbored the Remorin_N domain. Plenty of cis-elements related to stress and hormone response were identified in the promoters of most AnREM genes. Transcriptomic analysis showed that several AnREMs (such as AnREM1.1a, AnREM1.4b, AnREM1.4a, AnREM4.2b) were significantly induced by re-watering and/or heat stresses, while AnREM1.2b, AnREM1.4b, AnREM6.5a, AnREM6.5c and AnREM1.4e were down-regulated in response to half-waterlogging stress. A co-expression gene network centered around AnREMs was constructed, pathway enrichment analysis showed the potential roles of AnREMs in regulating reactive oxygen species (ROS) accumulation and stabilizing the cell membrane. Taken together, the results from this study indicated that AnREM1.1a, AnREM1.4b, AnREM1.4a and AnREM4.2b could serve as the potential molecular targets for improving the abiotic stress tolerance in A. nelumboides.