Induction signaling and its mechanism of hypersensitive cell death which is thought to be the rice defense responses

为了阐明水稻超敏性细胞死亡的诱导机制，本研究进行了两个方面的研究.水稻OsAMPK-γ在诱导过敏性细胞死亡中的作用利用诱导和未诱导过敏性细胞死亡的水稻培养细胞进行荧光差异显示。水稻OsAMPK-γ基因被鉴定为在过敏性细胞死亡过程中表达下调的基因。将DEX诱导型启动子控制的反义OsAMRK-γ基因转化水稻细胞。用DEX处理转基因培养细胞，可诱导转基因培养细胞发生过敏性死亡。结果表明，OsAMRK-_γ基因表达的下调参与了水稻过敏性细胞死亡的诱导.活性氧在诱导水稻细胞过敏性死亡中的作用为了阐明活性氧在诱导水稻细胞过敏性死亡中的作用，本研究以水稻细胞为材料，接种了不同浓度的外源基因，研究了外源基因对水稻细胞过敏性死亡的影响。 ...更多信息 测定了燕麦食酸菌（Acidovorax avenae，N1141）的H_2O_2产生量和过敏性细胞死亡率。用不亲和菌株N1141接种水稻培养细胞，在诱导细胞死亡之前就有H_2O_2产生。用Ce（OH）处理接种N1141菌株的水稻细胞，透射电镜观察Ce的积累，以确定H_2O_2产生的位置。细胞质膜与细菌接触处部分卷曲，细胞壁与质膜之间存在电子致密物质。H_2O_2的产生依赖于NADPH，DPI抑制H_2O_2的产生。因此，从水稻培养细胞中克隆了水稻NADPH氧化酶基因Osrboh A，并将反义Osrboh A转化到水稻培养细胞中。将不亲和菌株接种到反义转基因细胞上，没有检测到H_2O_2的产生，转基因细胞的过敏性死亡也被消除，表明Osrboh A产生的H_2O_2诱导了水稻过敏性细胞死亡。少

To clarify the induction mechanism of the hypersensitive cell death in rice, two researches were performed.1. Function of rice OsAMPK-_γ on induction of the hypersensitive cell deathFluorescence differential display was performed using the hypersensitive cell death inducing and non-inducing cultured rice cells. Rice OsAMPK-_γ gene was identified as down regulated genes during the hypersensitive cell death. Anti-sense OsAMRK-_γ gene controlled by DEX-inducible promoter was transformed into cultured rice cells. The hypersensitive cell death was induced in the transgenic cultured cells when the transgenic cultured cells were treated with DEX. The data indicate that downregulation of OsAMRK-_γ gene expression was involved in induction of the hypersensitive cell death in rice.2. Function of active oxygen species on induction of the hypersensitive cell deathTo clarify function of active oxygen species on induction of the hypersensitive cell death, cultured rice cells were inoculated with inc … More ompatible strain of Acidovorax avenae (N1141) and H_2O_2 generation and the hypersensitive cell death were measured. When cultured rice cells were inoculated with the incompatible N1141 strain, H_2O_2 generation was detected before the cell death induction. To examine the location of the H_2O_2 generation, the cultured rice cells inoculated with N1141 strain were treated with Ce (0H) and accumulated Ce was observed by TEM. Plasma membrane was partially convoluted at contact site to bacteria and electron dense material existed between plasma membrane and cell wall. The H_2O_2 generation was dependent on NADPH and inhibited by DPI treatment. Therefore, Osrboh A, NADPH oxidase gene of rice, was cloned from cultured rice cells and anti-sense Osrboh A was transformed into cultured rice cells. When the incompatible strain inoculated to the anti-sense transgenic cells, no H_2O_2 generation was detected and the hypersensitive cell death was also abolished in the transgenic cells, suggesting that H_2O_2 generated by Osrboh A induced the hypersensitive cell death in rice. Less