Functional characterization of （E）-β-caryophyllene synthase from lima bean and its up-regulation by spider mites and alamethicin

• Published in: 农业科学学报：英文版 2017, Vol.16 (10), p.2231-2238
• Main Author: LI Feng-qi FU Ning-ning ZHOU Jing-jiang WANG Gui-rong
• Format: Article
• Language: English
• Subjects: 倍半萜类化合物; 全长cDNA; 利马豆; 功能描述; 合酶; 实时定量PCR; 氨基酸序列; 石竹烯
• ISSN: 2095-3119; 2352-3425

（E）-β-Caryophyllene is a sesquiterpene compound widely distributed in plants and functions in plant defence. However, little is known about the sequence and function of （E）-β-caryophyllene synthase in lima bean （Phaseolus lunatus）. Here, we report a new full-length cDNA （PICAHS） encoding （E）-β-caryophyllene synthase, a possible key enzyme of plant defence. The cDNA of PICAHS contains an open reading frame of 1 761 bp, encoding a protein of 586 amino acids with a predicted mass of 67.95 kDa. The deduced amino acid sequence shows 52% identity with sesquiterpene synthase MtCAHS of Med- icago truncatula. Based on phylogenetic analysis, PICAHS is classified as the terpene synthases （TPS）-a subfamily. The recombinant enzyme, expressed in Escherichia coil, catalysed the formation of a major product （E）-β-caryophyllene （82%） and a minor product a-humulene （18%） from farnesyl dJphosphate. Real-time quantitative PCR （qRT-PCR） analysis found that the PICAHS transcript was significantly up-regulated in leaves after treatment with spider mites and alamethicin （ALA）, suggesting its ecological function in plant defence.