水杨酸和乙烯对依赖于Cf基因的过敏坏死的调控作用

Regulatory Effect of Salicylic Acid and Ethylene on Cf-dependent Hypersensitive Necrosis

通过农杆菌 (Agrobacteriumtumefaciens)介导的方法将互补Avr/Cf基因对同时在烟草叶片中表达 ,可以导致过敏性坏死反应。以水杨酸积累缺失型nahG和乙烯不应型etr1 1转基因烟草植株为材料 ,对水杨酸和乙烯在依赖于番茄Cf 4和Cf 9基因的过敏坏死中的调控作用进行了比较研究。结果表明 ,nahG植株产生的依赖于Cf 4的过敏坏死反应强度与野生型相似 ,依赖于Cf 9的坏死反应则明显轻于野生型。转etr1 1基因植株产生的依赖于Cf 4和Cf 9的坏死反应均轻于野生型 ,与依赖于Cf 4的坏死反应相比 ,转基因植株中依赖于Cf 9的坏死反应比野生型的减轻程度更显著。这些结果说明水杨酸可能对依赖于Cf 9的过敏坏死起重要调控作用 ,但对依赖于Cf 4的无此作用 ;而乙烯则对两者依赖性过敏坏死均起调控作用。

Transient expression of complementary Avr/Cf gene pair in planta through Agrobacterium-mediated approach resulted in hypersensitive necrosis in tobacco leaves (Fig.1). Regulatory effect of salicylic acid and ethylene on Cf-4- and Cf-9-dependent hypersensitive necrosis was compared in this study using nahG and etr1-1 transgenic tobacco plants which were defective in salicylic acid accumulating ability or ethylene perception respectively. It was found that Cf-4-dependent necrosis in nahG plants was similar to that in wild-type plants, whereas Cf-9-dependent necrosis in nahG plants was significantly weaker than that in wild-type plants. Both Cf-4- and Cf-9-dependent necrosis in etr1-1 transgenic plants was weaker than that in wild-type plants. The superiority of the etr1-1 transgenic plants over the wild-type plants in resistance against Cf-9-dependent necrosis was more pronounced than that against Cf-4-dependent necrosis (Fig.2). These results indicate that salicylic acid may play an important role in the regulation of Cf-9-dependent necrosis, but not Cf-4-dependent necrosis, while ethylene might be involved in the regulation of both Cf gene-dependent necrosis.