ACC氧化酶基因AhACOs对花生耐盐性的影响

Effect of ACC oxidase gene AhACOs on salt tolerance of peanut

摘要:

ACC氧化酶（ACC oxidase，ACO）是催化乙烯合成的关键酶之一，乙烯参与植物的盐胁迫反应过程，而盐胁迫严重影响花生产量。本研究通过对AhACOs基因的克隆及功能验证，探究AhACOs在花生盐胁迫响应中的生物学功能，为花生耐盐品种的选育提供基因资源。以花生耐盐突变体M29的cDNA为模板扩增得到基因AhACO1和AhACO2，与植物表达载体pCAMBIA super1300重组后，通过农杆菌介导的花粉管注射法将重组质粒转化到花育22号中。收获后切取籽仁远胚端部分子叶，利用PCR检测筛选阳性籽仁。利用qRT-PCR分析AhACOs基因表达量，通过毛细管柱气相色谱法检测植株的乙烯释放量。阳性籽仁和对照籽仁种植21 d后浇盐水，观察其表型变化。结果发现，盐胁迫后，转基因植株生长状况好于对照组花育22号，并且其叶绿素相对含量SPAD （soil and plant analyzer development）值和净光合速率（net photosynthesis rate，Pn）均高于对照组花生。另外，AhACO1和AhACO2转基因植株的乙烯释放量分别为对照组花生的2.79倍和1.87倍。这些结果表明AhACO1和AhACO2可显著提高花生的耐盐能力。

Abstract:

ACC oxidase (ACO) is one of the key enzymes that catalyze the synthesis of ethylene. Ethylene is involved in salt stress response in plants, and salt stress seriously affects the yield of peanut. In this study, AhACO genes were cloned and their functions were investigated with the aim to explore the biological function of AhACOs in salt stress response, and to provide genetic resources for the breeding of salt-tolerant varieties of peanut. AhACO1 and AhACO2 were amplified from the cDNA of salt-tolerant peanut mutant M29, respectively, and cloned into the plant expression vector pCAMBIA super1300. The recombinant plasmid was transformed into Huayu22 by pollen tube injection mediated by Agrobacterium tumefaciens. After harvest, the small slice cotyledon was separated from the kernel, and the positive seeds were screened by PCR. The expression of AhACO genes was analyzed by qRT-PCR, and the ethylene release was detected by capillary column gas chromatography. Transgenic seeds were sowed and then irrigated with NaCl solution, and the phenotypic changes of 21-day-seedings were recorded. The results showed that the growth of transgenic plants were better than that of the control group Huayu 22 upon salt stress, and the relative content of chlorophyll SPAD value and net photosynthetic rate (Pn) of transgenic peanuts were higher than those of the control group. In addition, the ethylene production of AhACO1 and AhACO2 transgenic plants were 2.79 and 1.87 times higher than that of control peanut, respectively. These results showed that AhACO1 and AhACO2 could significantly improve the salt stress tolerance of transgenic peanut.