一株淡紫紫孢菌12ID-1的分离及其对埃及吹绵蚧的致病性

Isolation of Purpureocillium lilacinum 12ID-1 and Its Virulence against Icerya aegyptiaca

从埃及吹绵蚧虫(Icerya aegyptiaca)体中分离出一株虫生真菌菌株12ID-1,对其进行了形态观察和r DNA ITS序列分析,同时优化了该菌株的产孢条件和测定了其不同浓度的孢子悬浮液对埃及吹绵蚧2龄若虫的致病性。结果表明:根据形态特征和分子鉴定结果,该菌株12ID-1为淡紫紫孢菌(Purpureocillium lilacinum);菌株12ID-1在SMAY培养基、28℃和光暗交替(14 L:10 D)的条件下产孢能力最强;致病性结果表明,当孢子浓度高于1×10^6孢子/m L时,随着12ID-1孢子浓度的增加,埃及吹绵蚧的校正死亡率越高,LT50值递减,在孢子浓度为1×10^8孢子/m L时,第7天校正死亡率接近100%,LT50为3.99 d;随着接种后时间的延续,LC50值递减,在接种后7 d,LC50值为1.3×10^6孢子/m L。可见淡紫紫孢菌12ID-1对埃及吹绵蚧具有较强的毒力,在埃及吹绵蚧生物防治中具有广阔的应用前景。

A fungal strain named12ID-1,was isolated from Icerya aegyptiaca,which was strongly virulent against I.aegyptiaca.The morphological characters and rDNA ITS sequence were examined and analyzed in the meanwhile,the condition of sporulation production and test the virulent effect of 12ID-1 against the2nd instar nymph of I.aegyptiaca were optimized.The results were showed as follows:12ID-1 was identified as Purpureocillium lilacinum based on its morphological characters and rDNA ITS sequence analysis.The optimum solid medium,temperature and light conditions for the growth and spore production of 12ID-1 were Sabouraud maltose agar supplemented yeast extract(SMAY),28℃,alternation of light and darkness(14L:10D)respectively.The virulence test indicated that the corrected mortality of I.aegyptiaca between concentrations increased with increment of concentration when the spore concentration was above 1×10^6 conidia/mL,while the values of LT50 were shortened.The corrected mortality was nearly 100%and the LT50 values was 3.99 d at a concentration of 1×10^8 conidia/mL.The estimates of the median lethal concentration(LC50)decreased with observation days,the estimates of LC50 on day 7 after inoculation was 1.3×10^6 conidia/mL.It is thus clear that P lilacinum 12ID-1 has high virulence to I.aegyptiaca,and 12ID-1 could be suitable for application in biocontrol of I.aegyptiaca.