Genome-wide investigation of aquaporin genes in Corchorus spp and their role in organ development and abiotic stress tolerance

Abstract

Aquaporins (AQPs), which are an essential type of membrane proteins, play roles in plant growth and stress tolerance by acting as channels for water homeostasis and nutrient uptake. These membrane proteins are important for the survival of different plant species under changing climates. However, the functional involvement of AQPs in jute is still unexplored. We conducted a genome-wide investigation into two cultivated jute species and identified 33 CoAQP and 31 CcAQP genes in the Corchorus olitorius and C. capsularis genomes, respectively. In both species, AQPs were classified into five phylogenetic subfamilies (PIPs, NIPS, SIPs, TIPs, and XIPs). Functional prediction of conserved NPA motif, ar/R selectivity filters, and Froger's position identified diversity in substrate specificity within the subfamilies of Jute AQPs. Investigation on putative cis-regulatory motifs revealed an enrichment of light, defense and stress responsiveness cis-element in the promoter regions. RNA-seq analysis showed the expression pattern of Co and CcAQPs under abiotic stresses and in organ development. Among the AQP genes, three (NIP6–1, SIP1–1, TIP4–1) were highly expressed in fiber cells, three (PIP1–1, PIP1–2, PIP2–1) in stem and leaf, and one (NIP7–1) in flower of both species. There were differential levels of expression patterns in response to salinity, drought, and waterlogging. In both species, two genes (XIP-1-1 and PIP1–3) showed a decreased level of expression with the increased level of waterlogging. Six AQPs (PIP1–1, PIP1–3, PIP2–1, NIP1–2 along with CcSIP1–2 and CoSIP2–1) showed upregulation under salt stress. On the other hand, two genes, PIP1–3 and PIP2–1, were overexpressed under drought stress. Results from this study provided detailed insights into the complexities of jute AQPs and their biological functions in adaptation, which can be useful for future varietal development programs.