Genome-wide identification, characterization of aquaporin gene family and understanding aquaporin transport system in hot pepper (Capsicum annuum L.)

The aquaporin gene family constitute essential channel proteins and is highly conserved which possess multiple functions all through plant growth, development and under stress conditions. They play a key role in transport of water and other solutes. In the present work, we report a comprehensive genome wide search for aquaporins in Capsicum annuum, a widely grown commercial crop. A total of fifty chilli aquaporins (CaAQPs) were identified and classified into five sub-families namely plasma membrane intrinsic proteins (PIPs), tonoplast intrinsic proteins (TIPs), NOD26-like intrinsic proteins (NIPs), small basic intrinsic proteins (SIPs) and xintrinsic proteins (XIPs) based on phylogenetic analysis. Functional prediction based on analysis of key amino acid residues viz., aromatic/arginine (ar/R) selectivity filter, Froger's Positions, Specificity Determining Positions demonstrated significant differences for substrate specificity among sub-families. Analysis of physical distribution of genes revealed uneven distribution of CaAQPs in genome. Drought induced expression pattern of CaAQPs, studied by qRT-PCR analysis illustrated varied and distinct expression profiles in various organs (leaves and roots) and between genotypes differing in drought tolerance. These results provide fundamental and indispensible insights into the role of the studied CaAQP genes under drought conditions. The present work contributes a reference and resource for further investigation of CaAQPs as candidate genes for genetic improvement studies of drought stress tolerance in hot pepper.

Automated summary

The study investigated aquaporin genes in Capsicum annuum, identifying fifty members categorized into five sub-families and predicting their functions based on amino acid residue analysis. The uneven distribution of CaAQPs in the genome and distinct expression profiles under drought induction were observed, providing fundamental insights for further investigation into the role of these genes in drought conditions.