作物学报2017，Vol.43Issue(10)：1480-1488,9.DOI:10.3724/SP.J.1006.2017.01480
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 Biosyn-thesis in Brassica napus
摘要
Abstract
Proline accumulation is a widespread metabolic adaptation in many organisms in response to various environmental stresses, 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 BnP5CS2 but 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 P5CS2 and 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 pattern of original genes in diploid was found for P5CS1 (BnaA.P5CS1.a and BnaC.P5CS1.d), P5CS2 (BnaA.P5CS2.a and BnaC.P5CS2.c). These results suggest that the gene sequence and expression pattern existing in allotetraploid (B. napus) were conserved, which is benefit to proline accumulation for plant adaptation to environmental stresses.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Key words
Polyploidization/Proline biosynthesis/Biased expression/Salt stress/Sub-functionalization引用本文复制引用
王翠平,华学军,林彬,刘爱华..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[J].作物学报,2017,43(10):1480-1488,9.基金项目
本研究由宁夏自然科学基金项目(NZ16215)资助. The study was supported by the Ningxia Natural Science Foundation of China (NZ16215). （NZ16215）
