乙酸对淡紫紫孢菌生长发育及杀线虫能力的影响

Effect of acetic acid on growth and development of Purpureocillium lilacinum and its nematocidal activity

为探究乙酸对淡紫紫孢菌生长发育及杀线虫能力的影响,比较了不同乙酸浓度下淡紫紫孢菌的生长速率、孢子萌发率、菌落形态及产孢量的变化。在0~200μg·mL^(-1)的浓度范围内,乙酸对淡紫紫孢菌的生长发育无抑制作用;淡紫紫孢菌在PDB中培养3 d后,发酵液中乙酸含量为146μg·mL^(-1),随着培养时间的增加,养分不断消耗,发酵液中乙酸产量逐渐减少;当碳源匮乏时,无乙酸产生。在碳源匮乏时,淡紫紫孢菌能够将乙酸根作为碳源利用,在3~10 mg·mL^(-1)的乙酸根浓度范围内,淡紫紫孢菌表现出较好的生长态势。此外,乙酸能够增强淡紫紫孢菌的杀线虫效果,随着乙酸浓度的增加,抑制根结线虫卵孵化和杀二龄幼虫(J2)的效果呈上升趋势。

To investigate the effect of acetic acid on the growth development and nematocidal activity of Purpureocillium lilacinum,the growth rate,spore germination and production,and colony morphology of P.lilacinum were assayed in the presence of acetic acid with different concentrations. The growth development of P.lilacinum was not impaired in the culture medium containing low-dosage acetic acid（200 μg·mL-1）. P. lilacinum could produce acetic acid with the concentration up to 146 μg·mL-1in PDB medium at 3 days post-inoculation,whereas the concentration of it was decreased when the carbon sources were gradually consumed in PDB medium. It was observed that limited carbon sources of culture medium resulted in none of acetic acid produced by P. lilcacinum. In addition,P. lilacinum exhibited good growing status in the medium containing acetate with concentrations ranging from 3 mg·mL-1to 10 mg·mL-1,which suggested that P. lilacinum could make use of acetic acid radical as its carbon source. Furthermore,acetic acid could enhance P. lilacinum nematocidal activity,and the concentration of acetic acid was positive correlation to the inhibition of egg hatch and lethal effect on second-stage juvenile（J2） of root-knot nematode caused by P. lilacinum.