State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China; College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China; Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China; Department of Biotechnology and Genetic Engineering, School of Life Sciences, Bharathidasan University, Tamil Nadu, India.
Department of Biotechnology and Genetic Engineering, School of Life Sciences, Bharathidasan University, Tamil Nadu, India.
Pestic Biochem Physiol. 2019 Jun;157:99-107. doi: 10.1016/j.pestbp.2019.03.012. Epub 2019 Mar 18.
The entmopathogenic fungus Lecaniicillium lecanii is a naturally available biological control and it is considered to be one of the best mycoinsecticide agents against the destructive insect pest Diaphorina citri Kuwayama. The present study aimed to extract and characterize the toxic insecticidal protein from L. lecanii and to assess the toxicity level against the Asian citrus psyllid the vector of Huanglongbing disease (HLB), also called citrus greening. Extracts of a toxic substance from submerged batch culture examined by sodium dodecyl sulfate-poly-acrylamide (SDS-PAGE), had a molecular weight of 45 kDa. The most abundant toxic metabolite was subjected to HPLC to purify and identified it by mass spectrometry. Subsequently, metabolite toxicity was tested against D. citri at three different concentrations (1%, 2%, and 3%). The results showed that the highest concentration had a significant maximum mortality at 120 h post application. Furthermore, we investigated the expression of the GAS1 gene which was previously identified to have a role in pathogenicity in in vivo studies in adult insect psyllids. Results of this study indicated that expression of the virulence factor gene was present at three concentrations of the fungal suspension post inoculation. This is the first study to provide this novel approach for the characterization of fungal mediated synthesis of a cuticle degrading soluble protein against the insect D. citri. The present results provide strong information on the in vivo expression of the GAS1 gene involved in fungal virulence pertaining to penetration of the insect cuticle, but not to inhibiting the growth of the host.
昆虫病原真菌蜡蚧轮枝菌是一种天然存在的生物防治剂，被认为是防治破坏性害虫柑橘木虱的最佳真菌杀虫剂之一。本研究旨在从蜡蚧轮枝菌中提取和表征有毒杀虫蛋白，并评估其对亚洲柑橘木虱（HLB 的传播媒介，也称为柑橘黄龙病）的毒性水平。通过十二烷基硫酸钠-聚丙烯酰胺（SDS-PAGE）检测的深层批量培养物中有毒物质的提取物的分子量为 45 kDa。对最丰富的有毒代谢物进行 HPLC 纯化，并通过质谱进行鉴定。随后，在三个不同浓度（1%、2%和 3%）下测试代谢物对柑橘木虱的毒性。结果表明，最高浓度在施药后 120 小时具有显著的最高死亡率。此外，我们研究了 GAS1 基因的表达，该基因在体内研究中被鉴定为与成虫昆虫木虱的致病性有关。本研究的结果表明，在接种真菌悬浮液的三个浓度下，毒力因子基因的表达都存在。这是首次针对针对昆虫柑橘木虱的角质层降解可溶性蛋白的真菌介导合成进行特征描述的研究。本研究结果提供了有关与昆虫角质层穿透有关的真菌毒力的 GAS1 基因体内表达的强有力信息，但与抑制宿主生长无关。
