茶树异胡豆苷合酶基因 CsSTR1 克隆及表达分析.

【Objective】The study aimed to explore the molecular characteristics and the expression regulation pattern of STR gene（CsSTR） in tea plant（Camellia sinensis）, so as to lay the foundation for further functional analysis of CsSTR gene and for mining the medicinal value of tea. 【Method】By employing the RACE technology, CsSTR1 gene was cloned. The physicochemical properties, protein structure, subcellular localization and phylogenetic relationship of CsSTR1 protein were studied by the methods of bioinformatics. Expression pattern of CsSTR1 gene was analyzed by qPCR. 【Result】The full length of CsSTR1 cDNA was 1382 bp, containing 92 bp 5′ UTR, 159 bp 3′ UTR, 1131 bp CDS. The CsSTR1 protein had 376 aa, with the molecular weight being 41.5 kD, the theoretical isoelectric point being 6.36, the instability index being 29.74, the aliphatic index being 88.94, and the grand average of hydropathicity being-0.077. Subcelluar analysis revealed that the CsSTR1 protein was localized in vacuole. The proportions of random coil, extended strand, α-helix and β-turn in the secondary structure of CsSTR1 protein were 42.82%, 29.79%, 16.76%, and 10.64%, respectively. The three-dimensional structure of CsSTR1 protein displayed as six-bladed β-propeller. The phylogenetic analysis revealed a close genetic relationship between CsSTR1 and rice OsSTRL2 protein. qPCR results showed that CsSTR1 gene was expressed in various organs of tea plant, with higher expression levels in buds, the first leaf, the second leaf and the third leaf, with lower expression levels in flowers and fruits. Up-regulation of CsSTR1 gene was seen under low temperature, PEG simulated drought stress, MeJA and SA treatments; Expression of CsSTR1 gene was down-regulated by ABA after 24-48 hours of the treatment. 【Conclusion】The results suggest that CsSTR1 has an important role in both the buds and leaves development of tea plant and defense response to adversity stress, MeJA, SA and ABA can regulate the CsSTR1 gene expression. [ABSTRACT FROM AUTHOR]