三种侵染柑橘木虱的蜡蚧菌属真菌的生物学特性

Biological characteristics of three Lecanicillium species infecting Asian citrus psyllids

菌株ZJLA08、ZJLP09和ZJLSP07为从柑橘木虱虫体中分离纯化的蜡蚧菌属真菌,经鉴定分别为渐狭蜡蚧菌Lecanicillium attenuatum、刀孢蜡蚧菌Lecanicillium psalliotae及1个新种Lecanicillium sp.,均对柑橘木虱具有强致病性。为明确这3个菌株的生物学特性,测定了温度、光照和紫外照射等条件对菌株生长、产孢和孢子萌发的影响。结果表明:25~30℃是菌株生长、产孢和孢子萌发的适宜温度;光照对菌株生长和孢子萌发影响不显著,但适当的光照有利于菌株产孢,如在连续光照条件下培养7 d后,菌株ZJLSP07、ZJLA08和ZJLP09的产孢量依次为6.72×108、6.13×108、10.38×108个·m L^(-1);紫外照射对3个菌株的生长、产孢和孢子萌发均产生显著的抑制作用,如紫外照射60 min对菌株ZJLSP07、ZJLA08和ZJLP09的产孢抑制率分别达38.32%、51.17%和32.41%,对孢子萌发的抑制率分别为81.43%、87.35%和78.14%;湿度高有利于菌株孢子的萌发,如在相对湿度为62%时,菌株ZJLSP07、ZJLA08和ZJLP09的孢子萌发率相比饱和湿度条件下分别下降了84.31%、86.21%和77.47%。在测试的3个菌株中,菌株ZJLP09的菌丝生长速率、产孢量、孢子萌发率等均显著高于其他2个菌株,且其对高温、低湿和紫外照射等具有更强的抗逆性。

Strains ZJLA08,ZJLP09 and ZJLSP07,Lecanicillium species isolated from Diaphorina citri cadavers,were identified as Lecanicillium attenuatum,Lecanicillium psalliotae and a new species of Lecanicillium,and showed strong pathogenicity against D. citri. In order to make clear the biological characteristics of these strains,effect of temperature,light and UV irradiation on mycelial growth,sporulation quantity and conidial germination were determined. The results showed that the optimum temperature for mycelial growth,sporulation quantity and conidial germination of these three strains was 25 ℃ to 30 ℃. Light did not exert significant effect on mycelial growth and conidial germination,while was beneficial to sporulation. The sporulation quantity of strains ZJLSP07,ZJLA08 and ZJLP09 were 6. 72 × 10^8,6. 13 × 10^8 and 10. 38 × 10^8conidia·m L^-1after 7 days of incubation under continuous light. UV irradiation exhibited a dose-dependent inhibition effect on mycelial growth,sporulation quantity and conidial germination. After exposure to UV light for 60 min,the inhibition rates to sporulation quantity of strains ZJLSP07,ZJLA08 and ZJLP09 were 38. 32%,51. 17% and 32. 41%,and to conidial germination were 81. 43%,87. 35%and 78. 14%,respectively. High humidity could facilitate conidial germination. At 62% relative humidity,the conidial germination rates of strains ZJLSP07,ZJLA08 and ZJLP09 dropped by 84. 31%,86. 21% and 77. 47%,compared to those at 100% relative humidity. The mycelial growth rate,sporulation quantity and conidial germination rate of strain ZJLP09 were higher than the other two under the same conditions,and had stronger tolerance to high temperature,low humidity and UV irradiation.