Biological Control Laboratory, Division of Entomology, ICAR-IARI, New Delhi, Delhi, India.
Zoology Department, DAV College (CCS University, Meerut), Muzaffarnagar, India.
PeerJ. 2023 Oct 26;11:e16030. doi: 10.7717/peerj.16030. eCollection 2023.
Cotton mealybug, (Tinsley) and cowpea aphid (Koch) are notorious polyphagous, hemipteran sap sucking insect pests. A recombinant toxin gene 'LqqIT1' from the scorpion (Ehrenberg) was cloned in the pAL1 fungal expression vector and then expressed in the entomopathogenic fungus (Balasmo) using genetic modification techniques. The genetically transformed strain (BbLqqIT1-3) and its un-transformed parent strain (Bb-C) were screened to infect the third instar nymphs of and first instar nymph of through leaf treatment and topical application (spray) method at 1 * 10 spores per ml concentration. The recombinant strain BbLqqIT1-3 was highly pathogenic against but non pathogenic to . BbLqqIT1-3 induced 72 and 43.33% mortality in nymphs 96 h after leaf treatment and topical application, respectively. The nymphs of infected with BbLqqIT1-3 displayed classical neurotoxic symptoms such as sluggishness, solublize and liquification of the body. Crude soluble toxin protein, BbLqqIT1a-CSE and Bb-WT-CSE was extracted from the BbLqqIT1-3 and Bb-C, respectively using ammonium sulphate precipitation method, and their oral toxicity was analyzed at 5 µg/ml concentration. The survival of the studied insects was negatively affected by the crude soluble toxin extracts. The LT values of BbLqqIT1a-CSE against and were 22.18 and 17.69 h, respectively. Exposure to crude soluble toxin extracts also accounted for the imbalance of ionic concentrations in the hemolymph of treated insects such as hyperpotassemia (3.53-8.18 meq/ml) in the and hypopotassemia (7.52-0.47 meq/ml) in . The transformed fungus BbLqqIT1-3 strain exhibited promising results in invitro study.
棉蚜和豇豆蚜是臭名昭著的多食性半翅目刺吸式害虫。从蝎子（Ehrenberg）中克隆了一个重组毒素基因'LqqIT1'，并将其克隆到真菌表达载体 pAL1 中，然后利用遗传修饰技术在昆虫病原真菌（Balasmo）中表达。通过叶片处理和叶面喷雾（喷洒）法，用 1 * 10 个孢子/ml 的浓度，对转化菌株（BbLqqIT1-3）及其未转化亲本菌株（Bb-C）进行了筛选，以感染三龄若虫和初龄若虫。重组菌株 BbLqqIT1-3 对 高度致病，但对 无致病性。叶片处理和叶面喷雾后 96 小时，BbLqqIT1-3 诱导 72%和 43.33%的 若虫死亡。感染 BbLqqIT1-3 的 若虫表现出典型的神经毒性症状，如行动迟缓、身体溶解和液化。用硫酸铵沉淀法从 BbLqqIT1-3 和 Bb-C 中分别提取粗可溶性毒素蛋白 BbLqqIT1a-CSE 和 Bb-WT-CSE，并在 5 µg/ml 浓度下分析其口服毒性。研究昆虫的生存受到粗可溶性毒素提取物的负面影响。BbLqqIT1a-CSE 对 和 的 LT 值分别为 22.18 和 17.69 小时。暴露于粗可溶性毒素提取物也导致处理昆虫血液中离子浓度失衡，如 中的高钾血症（3.53-8.18 meq/ml）和 中的低钾血症（7.52-0.47 meq/ml）。转化菌 BbLqqIT1-3 菌株在体外研究中表现出良好的效果。
