基于丹参基因组的COI1基因抗虫与次生代谢调控功能研究

Roles of SmCOI1 in pest resistance and secondary metabolism regulation based on Salvia miltiorrhiza Bunge genome

本草基因组学极大地推动了药用植物分子育种、次生代谢网络调控和品质成因等研究的进程.本研究基于本草基因组学,从模式药用植物丹参(Salvia miltiorrhiza Bunge)基因组中克隆丹参COI1(SmCOI1)基因并初步分析其蛋白特征及表达模式.利用RNAi技术获得丹参COI1沉默株系(iCOI1).抗虫性检测结果显示,与对照相比iCOI1株系叶片损伤指数上升,对昆虫咬噬耐受性减弱;同时,抗性相关基因WKRY70和NPR1的表达量在iCOI1株系中显著降低.进一步检测iCOI1株系中主要次生代谢产物合成与积累情况,结果表明iCOI1株系中迷迭香酸、丹酚酸B、隐丹参酮及丹参酮ⅡA的含量较野生型显著降低,其生源合成途径中的关键酶基因C4H,RAS,HCT,HMGR,GGPPS,CPS,KSL,CYP76AH1的表达量较野生型显著下调,且与丹参COI1的沉默显著正相关.上述结果表明,丹参COI1基因参与调控丹参抗虫性及主要次生代谢产物合成和积累过程.本研究为丹参抗性研究和次生代谢过程调控提供理论依据,也为优质高产药用植物品种选育奠定了基础.

Herb genomics is of great significance to studies of molecular breeding, secondary metabolite regulation, and quality control of medicinal plants. We isolated SmCOI1 gene from the medicinal plant Salvia miltiorrhiza Bunge by screening genome databases and analyzed the structure and expression pattern of this gene. For functional analysis, we down-regulated SmCOI1 expression in S. mi#iorrhiza （iCOI1s） via RNA interference. Tests conducted to examine pest resistance revealed that leaf damage scores of iCOI1s were much higher than those of wild-type plants, whereas the expression of defense genes （NPR1 and WRKY70） was significantly reduced in iCOIls. Major secondary metabolite contents of S. miltiorrhiza （rosmarinic acid, salvianolic acid B, cryptotanshinone, and tanshinones IIA） were significantly reduced compared with those of wild-type plants. Furthermore, the expression of key genes involved in tanshinones and salvianolic acid biosynthesis pathways （HMGR, GGPPS, CPS, KSL, CYP76AH1, C4H, RAS, and HCT） was also down-regulated in iCOI1 plants. Our results indicated that SmCOI1 plays a critical role in pest resistance and secondary metabolism regulation in S. miltiorrhiza, paving the way for the breeding of high-quality medical plants.