香蕉MaASR1基因通过ABA途径提高拟南芥抗旱性的作用机制

The Regulation Mechanism of Banana Transcription Factor Gene-MaASR1 for Improving the Drought Resistance of Arabidopsis by ABA Pathway

香蕉MaASR1基因在植物响应逆境胁迫时发挥着重要作用,为了进一步研究MaASR1基因转入拟南芥后增强其抗旱性的分子机制,运用DNA芯片技术来筛选野生型的拟南芥和转MaASR1基因的拟南芥在不做任何处理和干旱胁迫处理条件下的差异基因。对基因芯片中与ABA途径相关的上调和下调大于2倍的差异基因进行了荧光定量PCR的验证,实验结果发现在以上两种处理条件下,转MaASR1基因的拟南芥体内ABA的生物合成量比野生型拟南芥低,而ABA的降解量却升高。当受到干旱胁迫时,转基因拟南芥体内ABI5和ABF1基因的表达量会得到提高,而ABI5基因可以赋予转基因拟南芥株系耐旱性和抗旱性的功能是因为LEA类的蛋白被其调控表达和提高了ABA诱导基因的表达水平。ABF1基因发挥其提高转基因株系抗旱性的功能则可以通过参与ABA信号途径以及与其它的ABI类基因共同作用来实现。除此之外转基因拟南芥株系抗旱性的提高,与CBL/CIPK复合物参与的胁迫应答途径无关。以上结果为解析MaASR1基因作为转录因子通过ABA途径提高植物抗旱能力的分子机制奠定基础。

The banana MaASR1 gene plays an important role in plant response to stress. In order to further study the molecular mechanism of drought resistance for over expressing MaASR1 gene in Arabidopsis thaliana. DNA microarray was used to broad-spectrum screening the differentially expressed genes under natural and drought treatment in wild-type Arabidopsis thaliana and transgenic lines. The genes related to ABA pathway in the DNA microarray were verified by RT-PCR. The results showed that without any treatment and drought stress conditions,MaASR1 transgenic Arabidopsis compared with the wild type the ABA biosynthesis was decreased and the amount of degradation was increased. Under drought treatment the transfer of MaASR1 can improve the expression of ABI5 and ABF1. ABI5 could regulate the expression of part of the LEA protein and enhance the expression of ABA-induced gene which conferred Arabidopsis transgenic plants drought-tolerant and drought resistance. ABF1can play a role with other ABI genes in synergy and could participate in the ABA signaling pathway which conferred Arabidopsis transgenic plants drought resistance. The drought resistance obtained of MaASR1 transgenic lines was not through the CBL/CIPK complex to complete the stress response. The above results lay the foundation for the molecular mechanism of MaASR1 gene as a transcription factor to improve plant drought resistance through ABA pathway