Cloning Of Three Apple Sorbitol Transporter Genes (MdSOTs) And Their Expression In Two Aplle Cultivars Under Drought Stress

Plants share different drought resistance mechanisms, which carbohydrates act asosmotic adjustment substances in plants can not be ignored. The sugar transporters as themain decision factor of sugar transportation and storage, has been the attention of theresearchers at home and abroad. Through this research, the SOT expression patterns havebeen clear about in apple under drought stress. The main results are as follows:1. According to SOT conserved sequence of amino acids from apple genome,17sorbitol transporters were screened. They were divided into5groups together withsix-reported MdSOTs through cluster analysis, amino acid sequence homology comparison,transmembrane domain structure analysis.2. Three new SOTs which highly homologous with MdSOT5were cloned, wherein theMdSOT7comprising a1617bp ORF (open reading frame) encoding529amino acids;MdSOT8comprising a1617bp of ORF, encoding529amino acids; MdSOT9also including a1530bp of ORF, encoding510amino acids.3. The results of the positioning of Arabidopsis protoplasts showed that MdSOT7waslocated in the vacuole membrane, MdSOT8in the cell membrane and beaded arrangement,MdSOT9in the cell membrane.4. Real-time quantitative PCR results showed that three MdSOTs had different responsemodes under drought stress: the expression mode of the same gene in different apple varietieswas different. Overall, the order of their increasing expression multiple in ’Qinguan’ wasMdSOT8> MdSOT9> MdSOT7, which in ’ NaganoFuji No.2’ was MdSOT8> MdSOT7>MdSOT9. MdSOT7was intensified by drought stress which the highest upregulatedexpression multiple and trend were similar in the ’Qinguan’ and ’ NaganoFuji No.2’; Theconclusion for MdSOT8was as similar as MdSOT7excepted that the upregulated multiple ofMdSOT8was significantly higher than MdSOT7; MdSOT9in ’Qinguan’ subsequent increasein the first cut, but in the ’ NaganoFuji No.2’ in the first cut been raised again, inflection pointwas in the first day of controlling water.5. Leaf micromorphology and sugar may contribute to differences in drought toleranceby two apple cultivars...