枸橼C-05抗柑橘溃疡病相关PRR基因LYK5的初步鉴定  

Preliminary Identification of a PRR Gene LYK5 of Citron C-05 in the Resistance to Citrus Canker Disease

作　　者：郝晨星 符红艳[1] 严佳文[1] 戴素明[1] 吴启 马先锋[1] 李大志[1] 龙桂友[1] 邓子牛[1] Hao Chenxing;Fu Hongyan;Yan Jiawen;Dai Suming;Wu Qi;Ma Xianfeng;Li Dazhi;Long Guiyou;Deng Ziniu(National Center of Citrus Improvement,Changsha Subcenter,Horticulture and Landscape College,Hunan Agricultural University,Changsha,410128)

机构地区：[1]湖南农业大学园艺学院,国家柑橘改良中心长沙分中心,长沙410128

出　　处：《分子植物育种》2020年第9期2814-2826,共13页Molecular Plant Breeding

基　　金：国家自然科学基金面上项目(31572111)资助。

摘　　要：为筛选出抗溃疡病病菌相关PRR(Pattern Recognition Receptors)基因,本研究以接种了溃疡病菌Xcc的抗病种质枸橼C-05(JY C-05)和感病种质冰糖橙(BTC)、酸橙(SC)及早蜜椪柑(ZM)为研究对象,利用荧光定量PCR分析PRR基因的表达,结果显示PRR基因中的LYK5(LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE5)基因在枸橼C-05中表达上调而在其它感病种质中表达下调,表明LYK5基因可能与枸橼C-05抗溃疡病相关;对枸橼C-05和感病种质LYK5核酸序列及氨基酸序列进行差异分析,发现枸橼C-05 LYK5基因与冰糖橙、来檬(LM)有差异,但是与大香橼(DXY)和爪哇柠檬(ZWNM)LYK5基因相似度为100%,说明基因结构差异不是枸橼C-05的LYK5基因参与抗溃疡病的原因;进一步对其蛋白关键结构域进行比较分析,显示LYK5蛋白质信号肽第16位氨基酸、LysM基序区域(第203号氨基酸,第209号氨基酸)和蛋白激酶结构域(第394位,第449位,第468位,第492位,第647位氨基酸)存在差异;同时,对其三级结构进行比对发现枸橼C-05 LYK5蛋白结构与感病种质冰糖橙、来檬、爪哇柠檬和大香橼并无差异,进一步表明LYK5基因参与枸橼C-05抗溃疡病的过程不是由其蛋白结构差异所致。分析枸橼C-05和其他柑橘种质的LYK5启动子,大多数元件的差异不能区分抗病和感病柑橘种质,只有枸橼C-05缺失激活分生组织特异性调控元件,其他柑橘种质均有该元件,这是不是LYK5在接种Xcc的不同柑橘中表达差异的原因还有待进一步探究。To screen the PRR gene related to Xcc resistance,we used leaves inoculated with Xcc from Xcc-resistant germplasm Citron C-05,and the susceptible citrus genotype-’Bingtang’sweet orange,sour orange and’Zaomi’ponkan,respectively,as raw materials,and employed qPCR to analyze the expression of PRR genes.The results showed that LYK5 gene was upregulated in Citron C-05,while downregulated in susceptible citrus,which indicated that LYK5 gene may related to the Xcc-resistant of Citron C-05.The nucleonic and amino acid sequences of LYK5 gene showed that the LYK5 gene of Citron C-05 was different from’Bingtang’sweet orange and Mexican lime,but no difference was detected between Citron C-05 and the susceptible’Daxiangyuan’citron and’Java’lemon,suggesting that the variation of gene sequence was not to the reason of Xcc-resistance.Further comparative analysis of the key protein domains showed that there were differences in signal peptides(16 th),Lys M domains(203 th,209 th)and protein kinase domains(394th,449th,468th,492th,647th).The comparison of the tertiary structure showed that there was no difference between the LYK5 proteins structures of Citron C-05 and susceptible genotypes’Bingtang’sweet orange,Mexican lime,’Java’lemon and’Daxiangyuan’citron,which further indicated that the difference of protein structure was not the reason why LYK5 gene participated in the resistance to canker disease of Citron C-05.The promoters of LYK5 genes were cloned.Most of the elements could not distinguish the resistant and susceptible citrus germplasm.Sequencing result showed the cis-acting elements demonstrated variation among the analyzed genotypes,no clear division was observed between the resistant Citron C-05 and the susceptible genotypes,except for one element,meristem specific regulatory element,which was absent only in Citron C-05 and present in genotypes.Whether the promoter is the reason for the differential expression of LYK5 response to Xcc remains to be further investigated.

关 键 词：柑橘溃疡病 枸橼C-05 模式识别受体 LYK5 

分 类 号：S436.66[农业科学—农业昆虫与害虫防治]