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

为了阐明水稻过敏性细胞死亡的诱导机制，进行了两项研究。以水稻超敏细胞死亡诱导和非诱导培养的水稻细胞为材料，研究了水稻OsAMPK-_γ在诱导细胞死亡中的作用。水稻OsAMPK-_γ基因被鉴定为过敏性细胞死亡过程中的下调基因。将地塞米松诱导启动子控制的反义OsAMRK-_γ基因导入培养的水稻细胞。用地塞米松处理转基因细胞，可诱导转基因细胞发生过敏性细胞死亡。这些数据表明，OsAMRK-_γ基因表达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阐明活性氧在诱导水稻细胞过敏性死亡中的作用，用Inc.…接种水稻细胞。测定了较亲和的燕麦酸杆菌(N1141)菌株的H_2O_2产生和过敏性细胞死亡。用不亲和菌株N1141接种培养的水稻细胞，在细胞死亡诱导前检测到H_2O_2的产生。为了确定过氧化氢产生的位置，用Ce(0H)处理接种N1141菌株的水稻培养细胞，用透射电子显微镜观察Ce的积累。质膜与细菌接触处部分卷曲，质膜与细胞壁之间有电子致密物质存在。H_2O_2的产生依赖于NADPH，并被DPI抑制。为此，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基因导入水稻培养细胞。当不亲和菌株接种到反义转基因细胞中时，没有检测到H_2O_2的产生，转基因细胞中的过敏性细胞死亡也被消除，这表明Osrboh A产生的H_2O_2诱导了水稻的过敏性细胞死亡。较少

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