Potato belongs to the botanical family Solanaceae, which is the third most important plant family,
marked after the cereals and legumes, with an annual production of over 300 million tons. Its nutritional
value was recognized by western countries, and is now one of the staple foods in Europe and Northern
America. The consumption of potato in developing countries shows an increased trend in recent years.
China now is the largest potato producer in the world, reaching an annual production of 68 million tons.
P.infestans is the cause of potato late blight. The worldwide losses in potato production caused by late
blight have been estimated to cost $3 billion annually Potato breeding for late blight resistance was one of the earliest mankind practices in combating plant
pathogens by means of genetic improvement[2], but the disease has not been controlled by resistance
breeding so far because P. infestans ranks highest in the evolutionary potential[3], which made it difficult
to control. In previous R gene deployment, R gene monoculture had been rapidly overcome when
deployed separately[4]. R gene pyramiding had the shortcoming of linkage between resistance genes and
unfavorable ‘wild’ traits, and it would be broke down sooner of later due to its single resistance speciality
in the field. Chemical control was costly to farmers in developing countries and also raised
environmental concerns in developed countries. Furthermore, the pathogen could mutate itself to become
resistant to certain chemicals such as metalaxyl, a phenylamide used to control P.infestans [5].
Biological[6]and cultural control measures, such as antagonistic fungi, sanitation, and crop rotation
sometimes could be effective, but the effect remained limited due to difficulty in application. So, we
need to adopt integrated disease management that take pathogen and host traits into account.