Cloning and Expression Analysis of Sugar Beet Phosphatidylinositol Transfer Genes Related to Low Temperature

Phosphatidylinositol transfer proteins（PITP） exist in the inner membrane system of eukaryotic cells, which can improve the tolerance of plants in response to stress. In this study, 28 PITP genes were obtained from sugar beet（Beta vulgaris） genome. Under low temperature stress, four PITP genes most significantly related to low temperature stress were screened by RT-qPCR analysis and cloned from sugar beet. The four genes are named Bvsec14 with 776 bp, Bvsfh8 with 1 401 bp, Bvsfh11 with 1 519 bp and Bvpate4.2 with 1 604 bp and were located on chromosome 5, 9, 1 and 8 respectively, they all have a typical SEC14 conserved domain of PITP gene family. The subcellular localization prediction of four genes showed they were on cell membrane or cytoplasm by bioinformatics analysis, the structures of proteins encoded by four genes are mainly α-helix and irregular coil, many phosphorylation sites and the number of serine phosphorylation sites is the largest. According to the highly conserved SEC14 region of PITP compared with other species, the phylogenetic tree of four genes showed that they had the closest relative and PITP related to low temperature stress in sugar beet was analyzed and they were divided into four subgroups. There was no direct interaction between the proteins encoded by the four genes, and they had great differences in amino acid sequences. Under low temperature stress, RT-qPCR was used for expression analysis,analysis results showed that the four genes had inorganization specificity. Bvsfh11, Bvsfh8, Bvpate4.2 and Bvsec14 were overexpressed within 24 hours, the peak appeared at 2 h and 12 h, and the lowest expression was 1.8 times and the highest was 25 times of the control group. The above results showed that four genes were involved in the response of sugar beet under low temperature stress. This study provided a scientific theoretical basis for developing new sugar beet resistant varieties and further exploring the function of PITP.