橡胶树树皮中ACC氧化酶基因(HbACO7)的表达特性及功能探究  

Expression and Function of an ACC Oxidase Gene(HbACO7)from the Bark of Hevea brasiliensis

作　　者：王艺玮 冯仁军[1,2] 黄亚成 刘晓东 方永军 罗红丽[1] 唐朝荣[1] WANG Yiwei;FENG Renjun;HUANG Yacheng;LIU Xiaodong;FANG Yongjun;LUO Hongli;TANG Chaorong(Natural Rubber Cooperative Innovation Center,Hainan Province&Ministry of Education of PRC/College of Tropical Crops,Hainan University,Haikou,Hainan 570228,China;Hainan Key Laboratory of Tropical Brain Research and Transformation,Hainan Medical College,Haikou,Hainan 571199,China;Rubber Research Institute,Chinese Academy of Tropical Agricultural Sciences,Haikou,Hainan 571101,China)

机构地区：[1]天然橡胶省部共建协同创新中心/海南大学热带作物学院,海南海口570228 [2]海南医学院海南省热带脑科学研究与转化重点实验室,海南海口571199 [3]中国热带农业科学院橡胶研究所,海南海口571101

出　　处：《热带作物学报》2021年第9期2435-2442,共8页Chinese Journal of Tropical Crops

基　　金：国家自然科学基金项目(No.31825007);海南大学高层次人才科研启动资金。

摘　　要：天然橡胶是重要的工业原材料,主要来自橡胶树树皮中的乳管。乙烯能促进橡胶树乳管产胶和排胶,在树皮上施用乙烯利(一种乙烯释放剂)或乙烯可显著提高胶乳产量。基于本课题组前期获得的橡胶树基因组和转录组数据,克隆橡胶树中乙烯合成通路关键酶--1-氨基环丙烷基-1-羧酸(ACC)氧化酶基因家族(HbACOs)的全部8个家族基因,研究其组织表达模式。结果表明:在分析的7种组织中,尽管HbACO基因存在不同程度的冗余表达,但每种基因的组织表达模式具有明显的特异性,其中HbACO7是树皮中表达量最高的家族基因。HbACO7基因的表达在割胶季节的不同月份发生明显变化,其中在8月的表达量最高。成功构建了HbACO7基因的原核表达载体,实现其在大肠杆菌BL21中的诱导表达。纯化后的HbACO7重组蛋白具有明显的ACO酶催化活性,成功地催化了乙烯的体外合成。该结果将为后续橡胶树树皮中的乙烯生物合成调控机制研究提供参考。Natural rubber is an important industrial raw material,mainly harvested from the rubber-producing laticifers residing in the bark of rubber tree(Hevea brasiliensis).Previous studies reveal that ethylene promotes both latex flow and regeneration,and the application of ethrel(an ethylene generator)or ethylene on bark could stimulate latex yield.In this study,based on the Hevea genome and transcriptome database we previously constructed,eight HbACO genes encoding the Hevea ACC oxidase(ACO),a key enzyme in ethylene biosynthesis,were cloned and examined for their expression patterns in seven Hevea tissues.Although the HbACO genes exhibited varying degrees of redundant expression in the seven tissues examined,each retained a distinct pattern of tissue expression.Of the eight HbACOs,HbACO7 showed the highest expression in the bark.The expressions of HbACO7 fluctuated greatly with the change of tapping months,showing the highest level in August.The prokaryotic expression vector HbACO7 was successfully constructed,and the expression of HbACO7 protein was induced in E.coli BL21.The purified HbACO7 recombinant protein successfully catalyzed ethylene synthesis in vitro,indicating its functionality as an active ACO enzyme.This study would lay a foundation for further research on the regulatory mechanism of ethylene biosynthesis in the bark of rubber tree.

关 键 词：橡胶树 乙烯 生物合成 HbACO7 酶活 

分 类 号：S794.1[农业科学—林木遗传育种]