甘蓝型油菜脯氨酸合成相关同源基因的进化和差异表达分析  

Evolutionary Fate and Expression Pattern of Genes Related to Proline Biosynthesis in Brassica napus

作　　者：王翠平 华学军[2] 林彬 刘爱华 WANG Cui-Ping;HUA Xue-Jun;LIN Bin;LIU Ai-Hua(State Key Laboratory of Seedling Bioengineering, Ningxia Forestry Institute, Yinchuan 750004, China;Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;University of Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[1]宁夏林业研究院种苗生物工程国家重点实验室,宁夏银川750004 [2]中国科学院植物研究所,北京100093 [3]中国科学院大学,北京100049 [4]Department of Plant Science,University of Manitoba

出　　处：《作物学报》2017年第10期1480-1488,共9页Acta Agronomica Sinica

基　　金：宁夏自然科学基金项目(NZ16215)资助~~

摘　　要：以异源四倍体甘蓝型油菜(Brassica napus)及其二倍体祖先白菜(B.rapa)和甘蓝(B.oleracea)为对象,研究了脯氨酸合成途径关键酶基因P5CS和OAT的进化命运以及各自不同祖先来源的同源基因的差异表达情况。序列比对和进化分析表明,甘蓝型油菜中P5CS基因和OAT基因和其二倍体祖先的相对应基因高度同源;进化上,和二倍体亲本相比甘蓝型油菜P5CS2基因发生了1个拷贝的丢失,而OAT基因没有基因丢失现象;半定量RT-PCR结果表明,甘蓝型油菜中来自二倍体亲本白菜和甘蓝的P5CS2和OAT同源基因在所有检测器官中均表达,没有发生基因沉默;但是它们可能发生了亚功能化,不同祖先来源的2个P5CS2同源基因存在较弱的偏向性表达,不同器官的同源基因表达模式稍有不同;而OAT基因明显偏向于表达来自于甘蓝祖先的同源基因,OAT的2个同源基因的不同器官表达模式基本一致;盐胁迫处理后,来自于甘蓝的BnaC.P5CS1.d表达量显著高于来自于白菜的Bna A.P5CS1.a,表明盐处理条件下甘蓝型油菜偏向性表达BnaC.P5CS1.d。甘蓝型油菜的脯氨酸合成基因Bna A.P5CS1.a、BnaC.P5CS1.d及Bna A.P5CS2.a、BnaC.P5CS2.c的盐诱导表达模式均基本保持了亲本来源基因的特征。以上结果表明,与二倍体祖先相比,甘蓝型油菜中脯氨酸合成基因序列和表达模式均存在高度保守性,这可能说明了脯氨酸积累在进化上对植物的有利性。Proline accumulation is a widespread metabolic adaptation in many organisms in response to various environmental sstresses,and it was proved to play protective roles for plants under adverse conditions.Polyploidization is a prominent driving force during plant evolution and many important crops have experienced this process during their evolutionary history.Brassica napus(AACC)is believed to be a newly formed allotetraploid,evolving from the inter-specific hybridization of two diploids,B.rapa(AA)and B.oleracea(CC)followed by chromosome doubling.In this research,we studied the evolutionary fate of genes related to proline synthesis in allotetraploid(B.napus),and its diploids ancestors(B.rapa and B.oleracea),to explore the effect of polyploidition on homologous gene evolution.First,we obtained the genes for proline biosynthesis(P5CSs,OAT)by database searching,and studied the similarities and the expression regulation pattern of homologous genes in allotetraploid(B.napus),in comparison with its diploids progenitors(B.rapa and B.oleracea),in different organs and in response to salt stress.Sequence analysis and phylogenetic analysis revealed that BnaA.P5CS2.a,BnaA.P5CS2.b,and BnaC.P5CS2.c originated from BraA.P5CS2.a,BraA.P5CS2.b,and BolC.P5CS2.a,respectively;BnaA.OAT.a,BnaC.OAT.b originated from BraA.OAT.a and BolC.OAT.a,respectively.And,one copy of gene loss from B.oleracea occurred for BnP5CS2but not for BnOAT.Expression patterns of these homologous genes in response to salt stress in different organs were also characterized by semi-quantitive RT-PCR.In B.napus,two homologous gene pairs with different origins,BnaA.P5CS2.a and BnaC.P5CS2.c,BnaA.OAT.a and BnaC.OAT.b exhibited biased expression in different organs,implying possible sub-functionalization of P5CS2and OAT.The genes BnaA.P5CS1.a and BnaC.P5CS1.d with different diploid ancestors were induced by NaCl treatment,and the expression of BnaC.P5CS1.d was higher than that of BnaA.P5CS1.a,showing a biased expression.RT-PCR manifested that preservation of expression

关 键 词：甘蓝型油菜 脯氨酸合成 多倍化 偏向性表达 亚功能化 

分 类 号：Q943.2[生物学—植物学] S565.4[农业科学—作物学]