百脉根半胱氨酸蛋白酶基因在根瘤衰老过程中的表达分析  

Analysis of cysteine protease expression during nodule senescence in Lotus japonicus

作　　者：许泽远 苟洪兰 段柳剑 张忠明[1] XU Zeyuan;GOU Honglan;DUAN Liujian;ZHANG Zhongming(State Key Laboratory Agricultural Microbiology/College of Life Science&Technology,Huazhong Agricultural University,Wuhan 430070,China)

机构地区：[1]华中农业大学生命科学技术学院/农业微生物学国家重点实验室,武汉430070

出　　处：《华中农业大学学报》2019年第1期16-21,共6页Journal of Huazhong Agricultural University

基　　金：国家重点研发计划"七大农作物育种专项"(52016YFD0100702)

摘　　要：为明确半胱氨酸蛋白酶与定型根瘤衰老的相关性,通过与已鉴定的紫云英半胱氨酸蛋白酶AsNODf32进行序列比对分析,从百脉根中鉴定出2个与根瘤衰老相关的蛋白酶基因LjCyp1和LjCyp5。蛋白序列及结构分析表明,LjCyp1和LjCyp5同源性高达96.2%,均含有2个典型的半胱氨酸蛋白酶结构域和液泡定位信号肽,属于木瓜蛋白酶家族。体外酶活检测显示,2个蛋白都具有半胱氨酸蛋白酶活性。通过Realtime PCR和组织化学定位分析表明,2个蛋白酶基因主要在成熟和衰老的根瘤中表达。结果表明LjCyp1和LjCyp5可能在百脉根根瘤衰老过程中发挥重要作用。In order to explore the correlation between cysteine proteases and the senescence of determinate nodules,LjCyp 1 and LjCyp 5,associated with root nodule senescence were identified from Lotus japonicus by sequence alignment analysis with cysteine protease AsNODf32.The protein sequence and structure showed that the homology of LjCyp1 and LjCyp5 was as high as 96.2%,both of which contained two typical cysteine protease domains and vacuolar localization signal peptides,belonging to the papain family.In vitro enzyme activity assays showed that both proteins had cysteine protease activity.Real-time PCR and histochemical localization analysis showed that two protease genes were mainly expressed in mature and aged root nodules.The results indicated that LjCyp 1 and LjCyp 5 cysteine proteases may play an important role during nodule senescence in Lotus japonicus.

关 键 词：百脉根 半胱氨酸蛋白酶 根瘤衰老 共生固氮 

分 类 号：Q939.9[生物学—微生物学]