Genome-Wide Identification, Evolution, and Expression Profile of Aquaporin Genes inCoffea canephorain Response to Water Deficit

Aquaporins (APQs) belong to the major intrinsic protein superfamily and play a key role in the transport of water and other solutes across cell membranes.Cofe aquaporingenes assigned to five subfamilies including seven plasma membrane intrinsic proteins (PIP), 9 tonoplast intrinsic proteins (TIP), 11 NOD26-like intrinsic proteins (NIP), 3 small basic intrinsic proteins (SIP), and 3 X intrinsic proteins (XIP). Generally, the AQPs gene structure was conserved within each subfamily, with exon numbers ranging from one to five. The prediction of the aromatic/arginine selectivity filter (ar/R) and Froger's positions indicated a noticeable difference in substrate specificity between subfamilies. Synteny analysis revealed high conservation of aquaporin genes in coffee. In silico expression analysis of theCcAQPsgenes indicated that they were differentially expressed in various tissues. Members ofCcPIPsandCcTIPssubfamilies were validated by real-time quantitative analysis in leaves of two genotypes ofC. canephorawith contrasting responses to water deficit (clone 14: drought-tolerant and clone 109A: drought-susceptible). Under severe water deficit, the relative expression of isoforms of both genes decreased in clone 14 compared with that under the irrigated condition, while clone 109A showed comparatively higher mRNA levels, with the exception ofCcPIP1;2 in the stress condition. This study was the first to characterize and validate aquaporin genes inC. canephorain response to water deficit, and the findings may provide insights for biotechnological approaches to increase tolerance to drought.

Automated summary

Aquaporins play a key role in water and solute transport across cell membranes, while coffee aquaporin genes demonstrate high conservation. In silico expression analysis revealed significant differences in CcAQP genes expression across different plant tissues, and real-time quantitative analysis showed varying expression levels of different gene isoforms under water deficit conditions.