Expression of a Toll Signaling Regulator Serpin in a Mycoinsecticide for Increased Virulence
Expression of a Toll Signaling Regulator Serpin in a Mycoinsecticide for Increased Virulence
复制标题
Toll 信号调节器 Serpin 在 Mycoinsecticide 中的表达以增加毒力
DOI：
10.1128/aem.01197-14
复制
发表时间：
2014-05
影响因子：
4.4
通讯作者：
Fan Yanhua
中科院分区：
文献类型：
--
作者：
Lu Ruipeng;Wang Xin;Pei Yan;Fan Yanhua
摘要 丝氨酸蛋白酶抑制剂是普遍分布的丝氨酸蛋白酶抑制剂，可与目标蛋白酶共价结合以发挥其活性。丝氨酸蛋白酶抑制剂调节多种活性，特别是那些蛋白酶介导的级联反应活跃的活性。果蝇丝氨酸蛋白酶抑制剂 Spn43Ac 负向控制响应真菌感染而激活的 Toll 途径。昆虫病原真菌白僵菌为昆虫控制提供了化学农药的环保替代品。然而，杀霉菌剂的使用仍然受到限制，部分原因是功效问题（低毒力）和目标的顽固性（由于强烈的免疫反应）。由于 Spn43Ac 可以抑制 Toll 介导的防御反应激活，因此我们探索了一种新策略的可行性，即通过在真菌中表达 Spn43Ac 来改造昆虫病原真菌，使其毒力增加。与野生型亲本的50%致死剂量（LD50）相比，表达Spn43Ac（菌株Bb::S43Ac-1）的白僵菌的LD50降低了~3倍，对大蜡螟（Galleria mellonella）的中位致死时间缩短了~24%，并且在宿主中看到菌丝体增殖更快 血淋巴。体外和体内测定显示，在 Spn43Ac 存在的情况下，酚氧化酶 (PO) 的活化受到抑制，其中 Spn43Ac 介导的胰凝乳蛋白酶、胰蛋白酶、昆布多糖和脂多糖对活化的抑制按以下顺序发生：胰凝乳蛋白酶和胰蛋白酶 > 昆布多糖 > 脂多糖。 Spn43Ac 的表达对内源白僵菌来源的角质层降解蛋白酶 (CDEP-1) 的活性没有影响。这些结果扩展了我们对 Spn43Ac 功能的理解，并证实抑制昆虫免疫系统防御是改造昆虫病原真菌以提高功效的可行方法。
ABSTRACT Serpins are ubiquitously distributed serine protease inhibitors that covalently bind to target proteases to exert their activities. Serpins regulate a wide range of activities, particularly those in which protease-mediated cascades are active. The Drosophila melanogaster serpin Spn43Ac negatively controls the Toll pathway that is activated in response to fungal infection. The entomopathogenic fungus Beauveria bassiana offers an environmentally friendly alternative to chemical pesticides for insect control. However, the use of mycoinsecticides remains limited in part due to issues of efficacy (low virulence) and the recalcitrance of the targets (due to strong immune responses). Since Spn43Ac acts to inhibit Toll-mediated activation of defense responses, we explored the feasibility of a new strategy to engineer entomopathogenic fungi with increased virulence by expression of Spn43Ac in the fungus. Compared to the 50% lethal dose (LD50) for the wild-type parent, the LD50 of B. bassiana expressing Spn43Ac (strain Bb::S43Ac-1) was reduced ∼3-fold, and the median lethal time against the greater wax moth (Galleria mellonella) was decreased by ∼24%, with the more rapid proliferation of hyphal bodies being seen in the host hemolymph. In vitro and in vivo assays showed inhibition of phenoloxidase (PO) activation in the presence of Spn43Ac, with Spn43Ac-mediated suppression of activation by chymotrypsin, trypsin, laminarin, and lipopolysaccharide occurring in the following order: chymotrypsin and trypsin > laminarin > lipopolysaccharide. Expression of Spn43Ac had no effect on the activity of the endogenous B. bassiana-derived cuticle-degrading protease (CDEP-1). These results expand our understanding of Spn43Ac function and confirm that suppression of insect immune system defenses represents a feasible approach to engineering entomopathogenic fungi for greater efficacy.
登录
查看更多内容
影响因子：
2.9
作者：
N. Asada;N. Kawamoto;H. Sezaki
通讯作者：
N. Asada;N. Kawamoto;H. Sezaki
鳞翅目昆虫的免疫力。
影响因子：
--
作者：
通讯作者：
--
影响因子：
5.2
作者：
Keyhani NO
通讯作者：
Keyhani NO
影响因子：
56.9
作者：
Levashina, EA;Langley, E;Reichhart, JM
通讯作者：
Reichhart, JM
影响因子：
2.9
作者：
An, Chunju;Lovell, Scott;Kanost, Michael R.;Battaile, Kevin P.;Michel, Kristin
通讯作者：
Michel, Kristin