烟草NtMLO家族全基因组序列鉴定及表达分析

Genome-scale identification and expression analysis of NtMLO gene family in tobacco(Nicotiana tabacum L.)

为系统鉴定普通烟草(Nicotiana tabacum)基因组中白粉病感病基因NtMLO,通过构建已知拟南芥(Arabidopsis thaliana)和番茄(Solanum lycopersicum)MLO蛋白保守结构域的隐马尔可夫模型,获得烟草MLO家族候选序列共29个,对序列进行了基础理化性质、亚细胞定位和系统发育等分析。基础理化性质分析结果显示,NtMLO蛋白序列长度范围为479~605个氨基酸,理论等电点在7.02~9.50之间,富含碱性氨基酸,跨膜结构域数量为5~7个。亚细胞定位结果显示,该家族蛋白均定位于细胞膜上。通过对拟南芥、番茄、普通烟草、林烟草(N.sylvestris)和绒毛状烟草(N.tomentosiformis)等物种的共计90个MLO蛋白构建系统发育树,显示烟草中的MLO基因可分为5个亚组。通过定量PCR分析了不同亚组的19个NtMLO基因的组织表达特异性,发现除NtMLO3和NtMLO5两个基因在花中没有表达、NtMLO26在叶中没有表达外,其余NtMLO基因在根、茎、叶片和花组织中均有表达。本研究为全面了解烟草基因组中MLO基因提供相关信息。

For novel insights on MLO gene family,we identified MLO domain-contained members and examined their expression in different tissues in tobacco(Nicotiana tabacum).A total of 29 tobacco MLO genes were identified(NtMLO1–29)using conserved domain profile hidden Markov models.The result of bioinformatic analysis of NtMLO proteins showed the sequence length is between 479 to 605 amino acids;the isoelectric point is 7.02–9.50,riching in alkaline amino acids.The transmembrane domain of NtMLO proteins is between five to seven,and the result of subcellular localization show all of NtMLO proteins are located on plasma membranes.Phylogenetic analysis indicates that the MLO family can be classified into five subfamilies.The transcript abundances of 19 NtMLO genes on different clades in different tobacco tissues were quantified using qRT-PCR.There was no transcript of NtMLO3 and NtMLO5 in flowers,and no transcript of NtMLO26 in leaves.