高羊茅应答盐胁迫的AtSOS途径基因的效应分析

本研究在2015年采用基因工程技术改良高羊茅耐盐性,通过种植转基因耐盐草坪草达到改良土壤改善生态环境的目的。以草坪草成熟种子诱导的胚性愈伤组织为受体,通过农杆菌介导法将拟南芥AtSOS途径基因AtSOS1、AtSOS2-AtSOS3和AtSOS1-AtSOS2-AtSOS3分别导入高羊茅爱瑞3号中,经PCR检测、Southern blotting分析和RT-PCR鉴定,获得了能稳定表达的转基因株系。以转不同组合AtSOS基因的高羊茅植株和野生型植株为材料进行盐处理,每次处理重复3次,测定其生理生化指标、株高、Na⁺、K⁺离子含量、叶绿素含量,结果显示,盐胁迫下转基因植株的过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活性都显著高于对照植株,而丙二醛(MDA)和脯氨酸(Pro)含量的增加幅度均显著低于对照植株;盐胁迫下转基因和野生型植株叶片中的Na⁺、K⁺含量都增加;盐胁迫下所有植株的株高均呈下降趋势,各株系的叶绿素含量也减少,但是转基因(AtSOS1-AtSOS2-AtSOS3)植株的叶绿素含量增加。转AtSOS基因的高羊茅通过发挥AtSOS途径的作用,促进了植物体内Na⁺的外排,减轻了盐胁迫所导致的伤害,提高了植物的耐盐性。

Introduction of AtSOS pathway genes into tall fescue to improve salt tolerance

Our research group is aiming to genetically engineer tall fescue to improve its salt tolerance, so that it can be used as a salt-tolerant turf grass to improve the soil in salt-contaminated environments. To this end, a regeneration system was established for tall fescue. Using embryogenic calli as the experimental materials, three salt tolerance-related AtSOS pathway genes from Arabidopsis thaliana (AtSOS1, AtSOS2, AtSOS3) were introduced in different combinations into the genome of the tall fescue cultivar‘Arid3’ by Agrobacterium-mediated transformation. The transgenic plants showed increased salt tolerance. Genomic DNA was extracted from the transgenic tall fescue plants, and PCR detection, Southern blotting, and RT-PCR analyses were conducted. The tall fescue plants transformed with different AtSOS gene combinations and wild-type plants were subjected to salt treatment, with three replicates for each line. The physiological and biochemical indexes, plant height, and Na⁺, K⁺, and chlorophyll contents were determined. Under salt stress, the superoxide dismutase (SOD), peroxidase (POD), hydrogen peroxidase (CAT) activities were significantly higher in the transgenic plants than in the control plants, and the malondialdehyde (MDA) and proline (Pro) contents were lower than those in the control plants. In the NaCl treatment, the Na⁺ and K⁺ contents in leaves were increased in transgenic and in wild-type plants. Most of the transgenic plants and wild-type plants showed reduced plant height and chlorophyll content under salt treatment, however, the chlorophyll content of transgenic plants harboring AtSOS1-AtSOS2-AtSOS3 was higher than that in control plants. These results demonstrate that the introduction of AtSOS pathway genes into tall fescue can increase its Na⁺ content under salt stress, alleviate the symptoms of salt stress, and improve its salt tolerance.