Isolation and characterization of genes encoding lipid transfer proteins in Linum usitatissimum

Abstract

Very little is known about lipid transfer proteins from flax (Linum usitatissimum L.). In the present work, three genes encoding a lipid transfer protein (LTP) were isolated from flax, two of which encoded Type-1 and one Type-2 LTPs with molecular masses of about 9 and 7 kDa, respectively. The analysis of deduced amino acid sequence reveals that only Type 2 of the L. usitatissimum leaf specific LTP (LuLTP_Ls) had an N terminal signal peptide consisting of 23 amino acids. The phylogenetic analyses of LuLTP_Ls suggest their closest relatedness with respective proteins from Dimocarpus longan and Vitis vinifera. The gene expression analysis shows that LTP Type 1 genes, which include LuLTP_Ls1 and LuLTP_Ls3, were progressively expressed during leaf development, whereas LuLTP_Ls4 (Type 2) was expressed only at initial and terminal senescence stages of cotyledons. The results suggest that both types of LuLTP_Ls were differentially yet significantly expressed in cotyledons implicating their function in transport and scavenging lipidic skeletons for the benefit of other developing parts of the plant.

Keywords

• flax
• gene expression
• molecular cloning
• plant development
• rt-qpcr