甘蓝型油菜P5CSb和OAT基因在干旱胁迫下的表达分析

Expression Analysis of P5CSb and OAT Gene under Drought Stress in Brasscia napus

为了探明脯氨酸积累过程的分子机制,以耐旱性较强的甘蓝型油菜holiday为材料,应用酸性茚三酮染色法和RT-qPCR(实时荧光定量PCR,real-time quantitative PCR)技术分别检测在干旱胁迫0d(对照组)、1d、3d、5d、7d油菜根、茎、叶、花和青荚中脯氨酸含量以及控制其合成的关键基因P5CSb和OAT的表达量。结果表明,各器官中脯氨酸的含量和干旱胁迫时间成正比,不同器官中脯氨酸的含量存在明显的差异;P5CSb基因和OAT基因的表达量在不同器官中呈现表达特异性,P5CSb基因在青荚中随着干旱时间的增加无明显变化,在叶中逐渐上升,在其他器官中均表现为先升高后降低的趋势,OAT基因的表达量在茎中无明显变化,在叶和花中呈现先升高后降低趋势,在根和青荚中表现为上升趋势;三者对比结果显示,P5CSb基因和OAT基因共同控制脯氨酸的合成,且不同胁迫时间,2个基因所起的作用不同,其中P5CSb基因占主导地位。

Proline acted as an accumulated osmolyte that accumulates when plants are subjected to abiotic stress. P5CSb （Δ1’ pyrroline 5 carboxylate synthetase） and OAT were two key regulatory enzymes that played a crucial role in proline biosynthesis. The Brassica napus was grown under 0 day, 1 day, 3 day, 5 day, 7 day treatments of drought stress in early flowering period, and the various tissues （roots, stems, leaves, flowers and pods） were harvested for analyzing proline content, P5CSb gene and OAT gene expression levels. The expression patterns of P5CSb in Brasscia napus treated with drought stresses were examined using real time quantitative PCR. Data analysis revealed that proline accumulation after treatment of Brasscia napus with drought, and there were evident correlation between the expression of gene and the content of proline. The expression level of the P5CSb gene was significantly increased after 5 day drought stress in roots, while the trends of expression were nearly identical in leaves and flowers. The expressions of P5CSb gene maintained stably in the pods and gradually rise in leaf. The expressions of OAT gene increased but then decreased in leaves and flowers, it maintained stably in the stems and gradually rise in pods and roots. In contrast, proline content increased after stress application and was correlated with P5CSb and OAT expression. Under drought stress, the up regulated expression of P5CSb was higher than that of OAT. In summary,the P5CSb and OAT were stress inducible genes regulating the accumulation of proline in plants subjected to drought stress, and the two genes might play different roles in plant development. Compared with two genes, P5CSb gene played the senior part in response for drought stress. The result indicated that recovery is a specific physiological process following different patterns in different tissues. The two genes could have the potential to be used in improving drought stress tolerance of Brasscia napus. Understanding gene expression patterns of the stress responsive genes may provide insights into complex regulatory network of stress tolerance.