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.
作者
郝晨星
符红艳
严佳文
戴素明
吴启
马先锋
李大志
龙桂友
邓子牛
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)
出处
《分子植物育种》
CAS
CSCD
北大核心
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。
