亚磷酸钾对马铃薯晚疫病病原菌的作用机理

Action mechanism of potassium phosphite against potato Phytophthora infestans

为明确亚磷酸钾对马铃薯晚疫病病原菌的作用机理,通过菌丝生长速率法和显微观察技术研究亚磷酸钾对马铃薯晚疫病病原菌菌丝生长和游动孢子释放的影响,并分别采用半定量反转录-聚合酶链锁反应(reverse transcription-polymerase chain reaction,RT-PCR)及生物化学技术分析亚磷酸钾处理后马铃薯叶片防御基因表达、氧化酶活性以及可溶性蛋白含量的变化情况。结果表明,亚磷酸钾对马铃薯晚疫病病原菌菌丝生长和游动孢子释放均有明显的抑制作用,其抑制中浓度EC_(50)分别为24.03μg/mL和5.99μg/mL。接种晚疫病菌并经亚磷酸钾溶液处理的马铃薯叶片防御基因PR1、PR2表达量显著上调,接种8 d时表达量为银法利处理和清水对照的1.97～5.12倍;同时,过氧化物酶(peroxidase,POD)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)酶活性增强,其峰值分别达534.29、281.13和68.84 U/mg,为银法利处理和清水对照的1.18～3.52倍;可溶性蛋白含量也随之增加,峰值(0.85 mg/mL)分别为银法利处理和清水对照的1.85倍和3.15倍。表明亚磷酸钾可通过直接抑菌作用和诱导植物产生抗病反应从而达到防治病害的目的。

In order to explore the action mechanism of potassium phosphite against potato Phytophthora infestans, the method of mycelium growth rate and microscopic observation were used to detected the effect for mycelium growth and zoospore release of P. infestans treated with potassium phosphite,and the expression of defense genes, oxidase activity and soluble protein content in the treated leaves of potato were analyzed by RT-PCR and biochemical method, respectively, after being inoculated with P.infestans and application of the potassium phosphite. The results showed that potassium phosphite could inhibit the mycelium growth and zoospore release of P. infestans, and the EC50 values were 24.03,5.99 μg/mL, respectively. The expression of resistance related genes, including PR1 and PR2, were significantly increased by 1.97-5.12 times than CK(infinito and water treatment), after application of potassium phosphite. The activity of peroxidase(POD), superoxide dismutase(SOD) and catalase(CAT)were increased, the specific value of that were 534.29, 281.13, 68.84 U/mg, with 1.18-3.52 times than CK, and the soluble protein concentration were also increased, the specific value of that were 0.85 mg/mL,with 1.85 and 3.15 times than CK(infinito and water treatment), respectively. In conclusion, the potassium phosphite may against the pathogen of oomycetes by direct inhibition and induced resistance of host.