Cloning and expression of mevalonate kinase gene CsMVK in tea plant

ObjectiveMevalonate kinase gene(CsMVK)from tea plant was cloned,and its biological information and expression in different tissues and Oolong tea during fine manipulation procedure were analyzed,to provide theoreti-cal basis for exploring the formation machanism of aroma during tea processing.MethodGene CsMVK was amplified by RT-PCR,and the amino acid sequence of its encoded protein(CsMVK)was predicted by bioinformatics software. Ex-pressions of gene CsMVK in different tissues of tea plant and Oolong tea during fine manipulation procedure were ana-lyzed by real-time fluorescence quantitative PCR(qPCR).ResultThe full-length cDNA of cloned gene CsMVK(Gen-Bank accession number MF668187)was 1455 bp in length,containing a 1164 bp open reading frame(ORF)encoding 387 amino acids. The protein molecular was 41.18 kD and theoretical isoelectric point(pI)5.88. Protein CsMV contained two functional domains,GHMP_kinases_N domain and GHMP_kinases_C domain functional domain. It was primarily located in cytoplasm,with no transmembrane structure and signal peptide. The phylogenetic tree analysis showed that CsMVK and MVK of Panax notoginseng and Hedera helix belonged to the same category,which indicated that tea plant, P. notoginseng and H. helix had the closest genetic relationship. According to qPCR detection,expression of gene CsMVK in fruit was significantly higher than those in other tissues(P<0.05,the same below). The order of gene CsMVK expression levels was fruit>root>leaf>stem>flower. During fine manipulation procedure of Oolong tea,expression of gene CsMVK up-regulated from leaves to solar withering and down-regulated from solar withering to first tumblings. Through three tum-blings,the expression of gene CsMVK reached its peak before fixation and showed significant difference with other stages.ConclusionExpression of gene CsMVK might be related to aroma formation in tea processing.