关键词: 致病疫霉, 游动孢子, 产量, 培养时间, 低温诱导

Abstract: Phytophthora infestans is the pathogen of potato late blight, which poses a serious threat to potato production.In order to explore the optimal preparation conditions for the zoospores of P.infestans,after cultivation for 7—12 days,Petri’s solution was added to cultures,and sporangia was collected and counted.Five different low-temperature induction methods were used to prepare zoospores,and the effects of different culture time and different preparation methods on zoospore yield were studied.The lowtemperature induction methods were as follows:M1,the sample was stood at 10℃ for 30 min and then at 18℃ for 30 min;M2,the sample was stood at 4℃ for 30 min and then at 10℃ for 90 min;M3,the sample was left at 4℃ for 30 min and then at 10℃ for 60 min;M4,the sample was stood at 4℃ for 3 h;M5,the sample was stood at 4℃ for 2 h and then at 18℃ for 1 h.The results showed that with the extension of the cultivation time, the yield of sporangia increased rapidly first and then slowed down,finally basically stopped. As the cultivation time of sporangia increased,the zoospore yields obtained by different preparation methods increased first and then decreased.The yield of zoospores was the highest when sporangia were harvested from 9 day culture and there was no significant difference among different preparation methods.In summary,to quickly obtain zoospores in large quantities,the sporangia of P.infestans cultured for 9 days was stood at 10℃ for 30 min and then at 18℃ for 30 min.Or regardless of the preparation time,the 9-day-old sporangia was stood at 4℃ for 2 h and then at 18℃ for 1 h to obtain the largest number of zoospores.The yield of sporangia is not completely positively correlated with the yield of zoospores.

Key words: Phytophthora infestans, Zoospores, Yield, Cultivation time, Low-temperature induction