Poplar glycosylphosphatidylinositol-anchored lipid transfer proteins respond to osmotic stress by regulating fatty acid biosynthesis

Non-specific lipid transfer proteins (LTPs) comprise various protein families in plant responses to biotic and abiotic stresses. LTPGs encoding a glycosylphosphatidylinositol (GPI)-anchored lipid transfer protein are a large subgroup within the LTP family. We identified 36 PtLTPG genes in the poplar genome, divided into four subgroups based on phylogenetic analysis. A total of 29 PtLTPG genes were amplified from the poplar genome. PtLTPG1, 2, and 31 were localized to the plasma membrane and PtLTPG9 to the nucleus, suggesting functional dissimilarity. The PtLTPG genes were expressed in all poplar tissues tested, but the expression levels of PtLTPG7 and 11 were low. Most PtLTPG and FA-related genes were induced by abiotic stresses, and the expression patterns of PtLTPGs were associated with those of FA-related genes. The FA composition, including the ratio of linolenic acid to linoleic acid, was altered by osmotic stress. Taken together, our results show that PtLTPGs and FA-related genes mediate tolerance to osmotic stress by modulating the FA composition in poplar.

Automated summary

In this study, we identified 36 PtLTPG genes in the poplar genome and divided them into four subgroups. PtLTPG genes were expressed in various tissues of poplar, but with different expression levels. Most PtLTPG and FA-related genes were induced by abiotic stresses, and their expression patterns were associated with each other. Osmotic stress altered the FA composition.