利用田间抗病基因近等混合系防治马铃薯晚疫病

Potato Late Blight Control using R-gene Polyculture

马铃薯是世界上第四大粮食作物,是我国七大农作物之一。晚疫病是由致病疫霉菌(Phytophthora infes-tans)引起的毁灭性的病害,19世纪中叶曾造成举世闻名的“爱尔兰大饥荒”,至今仍然是马铃薯最严重的病害。提高抗晚疫病的水平是马铃薯育种的重要目标。马铃薯抗晚疫病育种是通过遗传操作来抵抗植物病害的最早的人类实践之一,但至今收效甚微,从野生种导入的抗病基因在田间很容易失效。马铃薯和致病疫霉菌的互作关系符合经典的“基因对基因”假说,只有马铃薯的抗病基因和致病疫霉菌的非毒力基因同时存在并表达时,抗病反应才能发生。致病疫霉菌是一种进化潜力非常高的病原,可以快速突变本身的非毒力基因,因而造成对应的马铃薯抗病基因的失效。要提高抗病基因的持久性,目前唯一的途径是同时释放多个抗病基因,人为造成田间抗病基因的多态性。马铃薯抗晚疫病基因的克隆取得了快速的发展,为通过转基因的手段创造田间抗晚疫病基因的多态性提供了基础。

Abstract： Potato （Solanum tuberosum L. ） is the fourth most important crop in the world and one of the top seven important crops in china. Late blight is a devastating disease of potato caused by Phytophthora infestans （Mont.） de Bary, which was the reason of the Great Irish Famine in 1 845. Today, late blight remains the No. 1 threat to potato production. It is urgent to improve the late blight resistance of potato cuhivars. Potato breeding for late blight resistance was one of the earliest practices mankind used to combat plant pathogens by means of genetic improvement, but the disease has not been controlled by resistance breeding so far. Resistance genes （R genes） introgressed from wild species broke down quickly. The potato-P, infestans pathosystem suits the gene-for-gene model, which states that resistance only occurs when the R genes in the host and the corresponding avirulence gene （Avr） are both present and expressed. P. infestans ranks highest in the evolutionary potential and it can easily mutate its Avr genes and thus overcome the only promising solution for late blight control is potato plants carrying corresponding R genes. So, to release several R genes simultaneously and to artificially create a resistance polymorphism in the field, a strategy so called R gene polyculture. Recently, scientists gained a great success in cloning R genes conferring late blight resistance, providing a basis to create R gene polycuhure by means of transgenic technology.