Cloning And Fuction Analysis Of Gossypium Hirsutum Lipid Transfer Protein Gene Family

As one of the most important crops, cotton is the main natural fiber resource in textile industry. How to improve fiber yield and quality has been a hot spot in cotton molecular breeding. Cotton fiber originates from the ovule epidermis cells and develops into mature fiber after four distinct and overlapping stages. Isolation and analysis of those genes involved in these processes will be aid to fully understand the mechanism of fiber development.Lipid transfer protein is a low molecular weight protein existed in most plants. An embedded hydrophobic cavity in LTP protein enables it to transfer phospholipids, fatty acid and glycolipids, which contribute to stresses resistance, defense against pathogen and signal conduction during pollen development. Previous stuides indicated that very long-chain fatty acids could activate fiber initiation and elongation by regulating intracellular ethylene signal transduction in cotton ovule. However, how fatty acids are transferred to the surface of fiber cells still remains unknown, as well as the number of genes involved in this process.In this study, we cloned11Gh-LTP genes after genome-wide search and analyzed their expression patterns during fiber’s development by quantitative RT-PCR. We named these Gh-LTP genes as following:GhLTPl-GhLTPlll (corresponding to GenBank NO.:KC342632--KC342642). qRT-PCR analysis between Xuzhou142and its mutant showed that Gh-LTP6,7,8,11might be closely related to cotton fiber development.Ecotopic expressed Gh-LTP6in Arabidopsis showed that transgenic plants had more branches and epidermal hairs in wild type, indicating its function in trichome development. But its function in cotton fiber development still needs to be confirmed in the future. Promoter analysis showed that Gh-LTP6promoter contains many MYB binding sites. However, yeast one hybridization results indicated that there was no obvious interaction between LTP6promoter and MYB2or MYB25.Phylogenetic analysis showed that Gh-LTP11(also named as Gh-LTPG) had highly homologues to At-LTPG1, while distantly from LTPs in cotton. Membrane Lipid Strips analysis demonstrated that Gh-LTPG had a strong combination with PIP, PS and Cardiolipin. These results together provided a hint for deeply analysis LTPs’functions during cotton fiber development.