植物耐铝的生物化学与分子机理

某些耐铝植物在铝胁迫下分泌有机酸被认为是一个重要的抗性机制.从根系分泌出来的有机酸能与根际的Al3 结合,形成无毒性的螯合物,从而减轻了铝对根系的毒害.但是,铝诱导有机酸分泌的中间环节及调节机制至今仍不清楚.一些证据表明,铝能激活根尖细胞质膜内的阴离子通道,因而可以调节有机酸的分泌.近年来,人们开始注意一些信号分子如蛋白激酶、水杨酸等介导铝诱导有机酸的分泌,已经获得一些成果.同时,铝胁迫基因的分离和鉴定也为人们从分子水平上研究和认识铝胁迫下植物的抗性机制奠定了基础.

Biochemical and Molecular Mechanism for the Aluminum Tolerance in Plants

Some plants exclude organic acids when exposed to toxic levels of aluminum. The exudation of organic acids is proposed to confer aluminum detoxification by forming Al organic acid complex. Although more than a dozen of Al tolerant plant species have been identified and demonstrated to secret organic acids, the regulatory processes leading to the organic acid efflux remain elusive. Activation of transport or anion channel by Al has been proposed to mediate efflux of organic acids. Recent progress in determining signal transduction components ( e.g . protein kinase, salicylic acid) that modulate the efflux activity of organic acids has been significant. However, a better understanding of the overall Al triggered signal transduction network needs more intensive investigations. Isolation and identification of Al induced stress genes have also evoked much interest. In this article, the key aspects of our recent biochemical and molecular understanding of regulatory mechanisms leading to organic acid exudation in response to Al are briefly described.