Poa pratensis ECERIFERUM1 (PpCER1) is involved in wax alkane biosynthesis and plant drought tolerance

Poa pratensis is a perennial turfgrass used worldwide. However, shortage of irrigation and drought induced by climate change adversely affect plant growth and turf quality. Cuticular wax covers plant aerial parts and plays important roles in decreasing plant water loss under drought-stressed conditions. Previous research proposed two candidate genes that were involved in wax very-long-chain alkane biosynthesis based on the transcriptome of Poa pratensis leaf. Here, one of the candidate genes, PpCER1-2 was further characterized. A subcellular localization study revealed that PpCER1-2 was localized on the endoplasmic reticulum. The expression of PpCER1-2 could be induced by drought and salt stresses. Overexpression of PpCER1-2 in Brachypodium distachyon increased the alkane amount, whereas decreased the amounts of primary alcohols and total wax. The relative abundance of C25 and C27 alkane and C26 aldehyde increased significantly, but the relative abundance of C29 and C31 alkane and C28 aldehyde decreased. Meanwhile, PpCER1-2 overexpression lines exhibited reduced cuticle permeability and enhanced drought tolerance. These results suggested that PpCER1-2 relatively promoted alkane biosynthesis by converting more very long chain fatty acids precursors into the decarbonylation pathway from the acyl-reduction pathway. Taken together, our data suggest that PpCER1-2 is involved in wax alkane biosynthesis in P. pratensis and plays important roles in improving plant drought tolerance.