| 蔡霓，龙秀珍，刘蓉，吴雨欣，曾宪儒，农向群，王广君，涂雄兵，张泽华,2022,一株白僵菌对红火蚁的毒力及对免疫酶活性与基因表达的影响[J].环境昆虫学报,44(6):1517-1527 |
| 一株白僵菌对红火蚁的毒力及对免疫酶活性与基因表达的影响 |
| Virulence and regulating immune-associated enzyme activity and gene expression of a Beauveria bassiana strain against red fire ants |
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| DOI： |
| 中文关键词: 球孢白僵菌 红火蚁 毒力 酶活 Toll通路 免疫 |
| 英文关键词:Beauveria bassiana Solenopsis invicta virulence enzyme activity Toll pathway immunity |
| 基金项目:国家重点研发计划项目（2021YFD1000500） |
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| 摘要点击次数: 183 |
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| 中文摘要: |
| 白僵菌是最具防治害虫潜力的一类昆虫病原真菌。本研究测定了球孢白僵菌Beauveria bassiana 237菌株对红火蚁Solenopsis invicta的感染毒力，并探究了白僵菌侵染对红火蚁免疫相关酶活性及相关基因表达的影响。结果显示，该白僵菌菌株对红火蚁的毒力较强，在孢子悬浮液108孢子/mL浓度下，对红火蚁的致死中时间LT50为5.288±0.2014 d；在10^4~10^8孢子/mL的不同浓度处理下，红火蚁死亡率随孢子浓度的增加而显著增加。经计算，第4~10天致死中浓度LC50值由8.82×10^6孢子/mL降低到8.95×10^5孢子/mL。红火蚁被球孢白僵菌感染后，体内保护酶和解毒酶发生了不同程度的改变。其中保护酶类酚氧化酶（PO）的活性在白僵菌处理后的第12 h已出现抑制，而在第24 h、48 h、72 h时均显著高于对照；超氧化物歧化酶（SOD）活性在12 h时与对照无显著差异，但在24~48 h阶段酶活显著上升，之后下降；过氧化物酶（POD）在较早时段保持与对照无显著差异水平，至中后期48~72 h出现持续升高。解毒酶类混合功能氧化酶系（MFO）的活性在整个检测时间段内表现为抑制-上升-抑制-上升的波动状态；谷胱甘肽S-转移酶（GSTs）活性的变化与SOD相似，只在24~48 h阶段出现上升。白僵菌还导致红火蚁免疫信号通路Toll途径相关基因表达量变化。在处理后12 h，识别因子GNBP1、Spaetzle即被激活，维持上调-回调波动趋势；而信号传递因子Myd88、pelle在检测的12~72 h内基本处于被抑制状态，只有Myd88在48 h时表达量上升；转录因子Dorsal以及抗菌肽Defensin在12~24 h都已被显著激活，而在后续48~72 h被抑制。综上所述，球孢白僵菌237菌株通过调节红火蚁酶活以及免疫相关基因的表达量实现成功侵染和致病作用，具有很高的生防应用价值。 |
| 英文摘要: |
| Beauveria is one genus of the most promising entomopathogenic fungi for pest bio-control. In this study, the virulence of Beauveria bassiana 237 strain to red fire ant Solenopsis invicta was determined, and the effects of the fungal strain on immune-related enzyme and gene expression level of the infected S. invicta was investigated. The results showed that B. bassiana 237 strain was highly virulent to red fire ants. At the fungal concentration of 108 spores /mL, the lethal medium time (LT50) of red fire ants was 5.288±0.2014 d. Under different concentrations of 10^4~10^8 spores /mL, the death rate of red fire ants increased significantly with the increase of spore concentration. The lethal medium concentration (LC50) decreased from 8.82×106 spores /mL to 8.95×10^5 spores /mL during the 4th to 10th day. After infected by B. bassiana, the protective enzymes and detoxification enzymes in red fire ants were changed to different degrees. The activity of phenol oxidase (PO), a protective enzyme, was inhibited at the 12th h after treatment with B. bassiana, but was significantly higher than that of the control at the 24th, 48th and 72th. The activity of superoxide dismutase (SOD) was not significantly different from that of the control group at 12 h, but increased significantly at 24~48 h and then decreased. The level of peroxidase (POD) was not significantly different from that of the control at the early stage, but subsequently increase at 48~72 h in the middle and late stage. For two detoxification enzymes tested, the activity of detoxification enzyme mixed functional oxidase system (MFO) fluctuated in a state of inhibition-increase-inhibition-increase during the whole detection period. The change of glutathione S-transferase (GSTs) activity was similar to SOD, and only increased at 24~48 h. In addition, B. bassiana also caused changes in the expression of immune-related genes of Toll signaling pathway in red fire ants. The genes of recognition factors GNBP1 and Spaetzle were activated at 12 h after treatment, maintaining an alternate up and down trend. The signal transfer factors, Myd88 and pelle, were overall suppressed during the 12~72 h detection, but only Myd88 increased expression at 48 h. The transcription factor Dorsal and the antimicrobial peptide Defensin have been significantly activated at 12~24 h then inhibited at 48~72 h. In conclusion, B. bassiana 237 strain successfully infected and caused disease to red fire ants by regulating the enzyme activity and the expression of immune-related genes in red fire ant, which has a high value of biocontrol application. |
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