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

发布时间：2018-10-23 15:39

【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。
[Abstract]:The evolutionary fate of P5CS and OAT genes of proline biosynthesis pathway and the differential expression of homologous genes from different ancestral sources of (Brassica napus) and diploid Chinese cabbage (B.rapa) and Brassica napus (B.oleracea) were studied by using allotetraploid Brassica napus (Brassica napus L.) and its diploid ancestors (B.rapa) and Brassica napus (B.oleracea). Sequence alignment and evolution analysis showed that P5CS gene and OAT gene were highly homologous to their diploid ancestors, and that P5CS2 gene of Brassica napus had a copy loss compared with diploid parent. The results of semi-quantitative RT-PCR showed that the autogenes of P5CS2 and OAT from diploid parent cabbage and cabbage were expressed in all the tested organs without gene silencing. However, they may have subfunctionalization. Two homologous genes of P5CS2 from different ancestors showed weak biased expression, and the expression patterns of homologous genes in different organs were slightly different. However, the OAT gene was inclined to express homologous genes from the ancestors of Brassica oleracea, and the expression patterns of two homologous genes of OAT were basically the same. The expression of BnaC.P5CS1.d from Brassica napus was significantly higher than that from Brassica campestris Bna A.P5CS1.a, which indicated that the expression of BnaC.P5CS1.d. in Brassica napus was biased under salt treatment. The salt-induced expression patterns of proline biosynthesis gene Bna A.P5CS1.aP5CS1.d and Bna A.P5CS2.aBnaC.P5CS2.c of Brassica napus maintained the characteristics of parental genes. These results suggest that proline synthesis gene sequences and expression patterns in Brassica napus are highly conserved compared with diploid ancestors, which may indicate the evolutionary advantage of proline accumulation in plants.
【作者单位】：宁夏林业研究院种苗生物工程国家重点实验室;中国科学院植物研究所;中国科学院大学;Department
【基金】：宁夏自然科学基金项目(NZ16215)资助~~
【分类号】：Q943.2;S565.4

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