论文部分内容阅读
【目的】研究昆虫病原真菌蜡蚧霉Lecanicilliurn lecanii(Zimmermann.)菌株No.V3.4504在不同培养基上继代培养,对菌种的菌落生长特性、胞外酶活力和对蚧虫致病力的影响。【方法】试验菌种蜡蚧霉菌株No.V3.4504是从染病蚧虫上分离的。试验蚧虫是沙里院褐球蚧Rhodococcus sariuoni Borchsenius和日本龟蜡蚧Ceroplastes japonicus Green。采用7种培养基继代培养多代。观察菌落形态特征、测定生长速率、产孢量、胞外蛋白酶和几丁质酶活性及对蚧虫的致死率。【结果】在PDA培养基上,菌落生长速率最快,但产孢量最低,胞外蛋白酶和几丁质酶的活性均呈逐代下降趋势,对两种蚧虫致死率也最低;增加蛋白胨对改善菌种致病力没有明显效果;在增加蚧虫尸体的D、E、F培养基上,菌落生长速率虽然较慢,但产孢量上升为8.83×106-9.13×106孢子/cm2。蛋白酶和几丁质酶的活性平均达到2.16-2.13 U/g和1.01-1.03 U/g,对两种蚧虫的致死率分别在55%-58%和39%-42%;在活蚧虫上连续培养3代,蛋白酶和几丁质酶的活性最高,为3.08-2.92 U/g和1.45-1.42 U/g,是PDA培养基上的1.6倍。对两种蚧虫的致死率也最高,分别达到71.30%和58.89%。蛋白酶和几丁质酶的活性与蚧虫死亡率呈正直线相关关系。【结论】采用PDA培养基连续多代培养会引起菌株No.V3.4504明显退化;在培养基中加入蚧虫尸体,对于保持菌种活力有明显效果;在活蚧虫体上继代培养对复壮菌种,提高菌种毒力的效果最佳。
【Objective】 The objective of this study was to investigate the growth characteristics of colony, extracellular enzyme activity and pathogenicity to scale insects of Lecanicilliurn lecanii (Zimmermann.) Strain No. V3.4504 on different media by subculturing, Impact. 【Method】 Test strain Coccidia molds strain No.V3.4504 was isolated from the disease scales insects. The test insects were Rhodococcus sariuoni Borchsenius and Ceroplastes japonicus Green. Seven kinds of culture medium were used to subcultivate multiple generations. Morphological characteristics of colony were observed, growth rate, sporulation rate, extracellular protease and chitinase activity and lethal rate to scale insects were measured. 【Result】 The results showed that in PDA medium, the colony growth rate was the fastest, but the sporulation rate was the lowest. The activities of extracellular protease and chitinase decreased from the previous generation to the lowest, There was no obvious effect on improving pathogenicity of the strains. On the other hand, the growth rate of colonies on D, E and F increased slowly but the sporulation increased to 8.83 × 106-9.13 × 106 spores / cm2. Protease and chitinase activity reached an average of 2.16-2.13 U / g and 1.01-1.03 U / g, respectively, with lethal rates of 55% -58% and 39% -42% for the two scale insects respectively; Three generations of continuous culture, protease and chitinase activity of the highest, 3.08-2.92 U / g and 1.45-1.42 U / g, PDA medium 1.6 times. The mortality of the two scale insects is also highest, reaching 71.30% and 58.89% respectively. The activities of protease and chitinase showed a positive correlation with mortality of scale insects. 【Conclusion】 The continuous culture of multiple subcultures in PDA medium caused the obvious degeneration of strain No.V3.4504. The addition of coccidian carcass to the culture medium had a significant effect on maintaining the viability of the strains. Rejuvenating strains to enhance the virulence of strains best.