Molecular genetic analysis of plant survival strategy by cell death

细胞程序性死亡是一种典型的细胞死亡现象，在许多生物体中早已发现。虽然对植物细胞死亡的机制细节知之甚少，但分子机制的某些方面在植物和动物之间是保守的。本研究的目的是找出利用细胞死亡机制与胁迫生物学相关的基本策略。特别感兴趣的是鉴定负责细胞死亡的基因，以及将这些基因应用于植物抗逆分子育种。在这种背景下，一些新的基因，调节细胞死亡，是耐人寻味的。事实上，这些基因也可以防止真菌感染和氧化应激。另一个很好的例子可以在下面的例子中看到。过量表达NADPH还原酶的水稻表现出对稻瘟病以及各种非生物胁迫如紫外线辐射、盐和淹水的抗性增强。大量研究表明，H_2O_2是一种重要的细胞介质，在生物和非生物胁迫条件下，H_2O_2都能调节细胞的生长、发育和启动细胞防御系统。在这项研究中，我们首次证明，NADPH还原酶是响应NADPH和NADP的氧化还原状态，这反过来又刺激整个植物的抗逆性。总之，我们提出的证据表明，细胞死亡调节剂可以用于抗逆作物分子育种的新工具的应用，这将是容易获得的可持续农业。

Programmed cell death is a typical phenomenon, which has been known long time in many organisms. Although relatively little is known about the mechanistic details of cell death in plants, some aspects of the molecular machinery are conserved between plants and animals. This study was intended to find out the basic strategy to use cell death mechanism in relation to stress biology. Special interest has been paid in terms of identifying genes responsible for cell death, and application of such genes in molecular breeding of plants for stress resistance. In this context, some new genes, which regulated cell death, are intriguing. In facts, such genes also work to prevent fungus infestation as well as oxidative stress. Another good instance can be seen in the following example. The phenotype of over-expressed NADPH reductase lines of rice showed enhanced resistance to rice blast disease as well as various abiotic stresses, such as UV radiation, salt and submergence. This apparently indicates that such gene plays a role in plant defense systems via a new pathway under biotic and abiotic stress.A great deal of evidence has shown that H_2O_2 functions as an important cellular mediator regulating cell growth, development and triggering cell defense systems in both biotic and abiotic stresses. In this study, we demonstrated for the first time that NADPH reductase is responsive for redox state of NADPH and NADP, which in turn stimulate stress resistance as a whole plants. In conclusion we presented the evidence that cell death regulators can be used for the application of new tools of molecular breeding of stress resistant crops, which would be readily available for the sustainable agriculture.