Sarracenia purpurea glycerol-3-phosphate acyltransferase 5 confers plant tolerance to high humidity in Arabidopsis thaliana.

Suberin, as a lipid polyester barrier, limits the movement of gas, water, and solutes, and plays important roles in plant protection and growth. In this study, a CDS encoding glycerol-3-phosphate acyltransferase 5 (GPAT5) was cloned from Sarracenia purpurea to investigate the gene function. SpGPAT5 shares 72% identity and 80% similarity to AtGPAT5 that is required for suberin synthesis. Fluorol Yellow 088 staining showed that the S. purpurea pitcher (specific leaf) tube contained more suberin in the adaxial surface compared to the lid, and SpGPAT5 transcripts were detected in the pitcher. Previous reported Atgpat5-1 phenotypes were complemented with SpGPAT5 showing that the Atgpat5-1 seed coat had increased permeability of tetrazolium red and the mutant was sensitive to salt. We also found that SpGPAT5 was able to revert the hyperhydric phenotype of Atgpat5-1 under high humidity. Thus, this study suggests that SpGPAT5 can functionally replace AtGPAT5 and contributes to plant tolerance to high humidity, which maybe assist in understanding the role of suberin-associated waxes in S. purpurea pitchers for water retention.