Han Zhenzhen, Xie Yingping, Xue Jiaoliang, Fan Jinhua
College of Life Science, Shanxi University, Taiyuan 030006, China.
Wei Sheng Wu Xue Bao. 2010 Feb;50(2):211-21.
The strain No. V3.4504 of Lecanicilliurn lecanii (Zimmermann), an entomopathogenic fungus, was studied on the effect of successive multi-generation culture in seven different media on its colony growth characteristics, extracellular enzyme activities and the virulence against scale insects.
The strain No. V3.4504 of L. lecanii was original isolated from a natural infected scale insect. The two species of scale insects used were Rhodococcus sariuoni Borchsenius and Ceroplastes japonicus Green. Seven media were used and fungus colony characteristics, growth rate and sporulation, extracellular protease and chitinase activity, and infective effect against the two species of scale insects were conducted.
The fungus cultured on PDA medium for successive nine generations showed the most fast in colony growth, the minimal in sporulation, straight decline of extracellular protease and chitinase activity with generation increasing, and the minimal mortality of the scale insects. There was no significant effect to promote virulence of the fungus by increasing peptone into medium. On the media D, E and F, that with the body materials of the two scale insects, although the fungus appeared lower in the colony growth rate, its sporulation was higher upward 8.83 x 10(6) - 9.13 x 10(6) spores/cm2, extracellular protease and chitinase activities averagely reached 2.16 - 2.13 U/g and 1.01 - 1.03 U/g respectively, and the mortalities of the two scale insects were 55% - 58% and 39% - 42% respectively. Cultured three generations in vitro of the two scale insects, the fungus exhibited the highest activities in its protease and chitinase that were 3.08 - 2.92 U/g and 1.45 - 1.42 U/g respectively and the best infection effect against the two scale insects with mortalities of 71.30% and 58.89% respectively. A linear correlation was found between extracellular protease and chitinase activities of the fungus and the mortalities of the scale insects.
Cultured on PDA medium successive multiple generations made retrogradation of the strain No. V3.4504 of of L. lecanii. It was significant effect on keeping the vigor and higher virulence of the fungus adding the body materials of the scale insects into the medium. The vitro by using live scale insects as medium materials was the best way for the rejuvenation of the entomopathogenic fungus and promoting its virulence.
研究昆虫病原真菌蜡蚧轮枝菌（Lecanicilliurn lecanii (Zimmermann)）V3.4504菌株在七种不同培养基上连续多代培养对其菌落生长特性、胞外酶活性及对蚧虫毒力的影响。
蜡蚧轮枝菌V3.4504菌株最初从自然感染的蚧虫中分离得到。所用的两种蚧虫为柳蛎盾蚧（Rhodococcus sariuoni Borchsenius）和日本龟蜡蚧（Ceroplastes japonicus Green）。使用了七种培养基，对真菌菌落特征、生长速率和产孢量、胞外蛋白酶和几丁质酶活性以及对两种蚧虫的感染效果进行了研究。
在PDA培养基上连续培养九代的真菌菌落生长最快，产孢量最少，胞外蛋白酶和几丁质酶活性随代数增加直线下降，对蚧虫的死亡率最低。向培养基中增加蛋白胨对提高真菌毒力没有显著影响。在添加两种蚧虫虫体材料的D、E和F培养基上，真菌虽然菌落生长速率较低，但其产孢量较高，达8.83×10(6) - 9.13×10(6) 个孢子/cm2，胞外蛋白酶和几丁质酶活性平均分别达到2.16 - 2.13 U/g和1.01 - 1.03 U/g，对两种蚧虫的死亡率分别为55% - 58%和39% - 42%。两种蚧虫在体外培养三代后，真菌的蛋白酶和几丁质酶活性最高，分别为3.08 - 2.92 U/g和1.45 - 1.42 U/g，对两种蚧虫的感染效果最佳，死亡率分别为71.30%和58.89%。真菌的胞外蛋白酶和几丁质酶活性与蚧虫死亡率之间存在线性相关性。
蜡蚧轮枝菌V3.4504菌株在PDA培养基上连续多代培养会导致菌株退化。在培养基中添加蚧虫虫体材料对保持真菌活力和提高毒力有显著效果。以活蚧虫为培养基材料进行体外培养是昆虫病原真菌复壮和提高其毒力的最佳方法。
