【摘要】 酮脂酰ACP还原酶(β-ketoacyl-(ACP)reductase,KAR)和烯脂酰ACP还原酶(β-enoyl-(ACP)reductase,ENR)是脂肪酸合成过程中2个关键的还原酶,主要负责脂肪酸碳链的延伸。为明确棉花同源基因的功能,克隆了陆地棉Gh KAR和Gh ENR基因,并构建表达载体;应用花粉管通道法转化棉花,经过PCR检测和Southern杂交,筛选出阳性单拷贝植株,分析其后代株系中目的基因对油分含量以及抗寒性的影响。通过对转基因T4株系含油量的测定,发现转基因株系种子的含油量比野生型对照提高10.2%~14.1%,与对照差异极显著。通过气相色谱法分析转基因株系种子的脂肪酸成分,发现不饱和脂肪酸含量比野生型对照增加4.04%~6.02%。测定4℃低温胁迫下各个转基因株系不同时间生理指标的变化,结果表明:转基因株系的相对电导率和脯氨酸含量积累明显高于对照,而丙二醛含量低于对照,在不同胁迫时间与对照表现出显著或极显著差异,过表达的转基因株系的抗寒性有所提高。更多还原

【Abstract】 Cotton is an important economic crop, and fatty acids account for 25%-40% of cottonseeds. A positive correlation exists between the unsaturated fatty acid content and cold tolerance. Gh KAR and Gh ENR are two reductase genes that are responsible for carbon-chain extension, which is related to fatty acid synthesis in cotton. Here, we built two vectors that over-expressed Gh KAR and Gh ENR independently, and then separately transferred the vectors into upland cotton by means of the pollen tube channel. The positive transformants containing single vector copies were obtained after being identified by PCR and Southern hybridization. The objectives of this research were to explore the gene functions and to provide candidate genes for high-oil and abiotic stress-resistance breeding in cotton. The oil contents in transgenic T4 lines were 10.2%-14.1% higher than that of the control(wild type). The fatty acidcompositions of transgenic lines were analyzed by gas chromatography and revealed that the unsaturated fatty acidcontent increased by 4.04%-6.02% compared with the control. Additionally, the cold tolerance of the transgenic lines was investigated under low-temperature(4 ℃) stress. The changes in the physiological indexes were evaluated. The relative electric conductivity and proline contents of the transgenic lines were remarkably or extremely higher than those of the control, but the malonaldehyde contents were remarkablylower in all periods of stress treatment. The results indicated that the transgenic lines could potentially be used in improving cotton’s cold tolerance.更多还原