Program in Molecular Medicine, UMASS Chan Medical School, Worcester, Massachusetts, United States of America.
Department of Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August University of Göttingen, Göttingen, Germany.
PLoS Negl Trop Dis. 2024 Oct 25;18(10):e0012611. doi: 10.1371/journal.pntd.0012611. eCollection 2024 Oct.
Bacillus thuringiensis crystal (Cry) proteins have been expressed in commercial transgenic crops for nearly 30 years, providing safe and effective control of insect pests and significantly reducing the application of hazardous chemical pesticides. B. thuringiensis crystal proteins have also been shown to target parasitic nematodes, including plant parasitic nematodes. Recently, transgenic soybean crops expressing Cry14Ab have been shown to provide control against the soybean cyst nematode Heterodera glycines, marking the first time a crystal protein is being commercialized in transgenic crops for control of a nematode pest. However, apart from H. glycines and the free-living nematode, Caenorhabditis elegans, the breadth of nematode activity of Cry14Ab, e.g., against gastrointestinal parasitic nematodes (GINs), has not been reported. Here we study the efficacy of Cry14Ab against a wide range of gastrointestinal nematode parasites (GINs) in vitro and in vivo. We find that Cry14Ab is effective in vitro against the barber's pole worm Haemonchus contortus larvae, small strongyles cyathostomin larvae, the hookworm Ancylostoma ceylanicum adults, the roundworm Ascaris suum L4 larvae, and the whipworm Trichuris muris adults. In rodents infected with GIN parasites, Cry14Ab is effective as an in vivo anthelmintic against the hookworms A. ceylanicum and N. americanus, against the mouse parasite Heligmosomoides polygyrus bakeri, and against the roundworm A. suum. Cry14Ab also variably reduces the reproduction of the whipworm T. muris in vivo. Using optimized profile Markov Models, we looked for other putative anthelmintic Cry proteins and, within this list, identified a Bt crystal protein, GenBank accession no. MF893203, that we produced and demonstrated intoxicated GINs. This protein, with 90% amino acid identity to Cry14Ab, is active against C. elegans, A. ceylanicum adults, and A. suum L4 larvae in vitro. MF893203 was given the official designation of Cry14Ac. Cry14Ac is also an effective in vivo anthelmintic against A. ceylanicum hookworms in hamsters and intestinal A. suum in mice. Taken together, our results demonstrate that Cry14Ab and Cry14Ac have wide therapeutic utility against GINs.
苏云金芽孢杆菌晶体（Cry）蛋白已在商业转基因作物中表达近 30 年，为防治害虫提供了安全有效的方法，并显著减少了危险化学农药的使用。苏云金芽孢杆菌晶体蛋白也被证明可以靶向寄生线虫，包括植物寄生线虫。最近，表达 Cry14Ab 的转基因大豆作物已被证明可以防治大豆胞囊线虫 Heterodera glycines，这标志着首次将晶体蛋白商业化用于防治线虫害虫。然而，除了 H. glycines 和自由生活线虫 Caenorhabditis elegans 之外，Cry14Ab 对线虫活动的广泛作用，例如对抗胃肠道寄生线虫（GINs），尚未有报道。在这里，我们研究了 Cry14Ab 对广泛的胃肠道线虫寄生虫（GINs）在体外和体内的功效。我们发现 Cry14Ab 在体外对旋毛虫 Haemonchus contortus 幼虫、小的 Strongyles cyathostomin 幼虫、钩虫 Ancylostoma ceylanicum 成虫、蛔虫 Ascaris suum L4 幼虫和鞭虫 Trichuris muris 成虫有效。在感染胃肠道线虫寄生虫的啮齿动物中，Cry14Ab 作为体内驱虫剂对钩虫 A. ceylanicum 和 N. americanus、鼠寄生虫 Heligmosomoides polygyrus bakeri 以及蛔虫 A. suum 有效。Cry14Ab 还可在体内不同程度地减少鞭虫 T. muris 的繁殖。使用优化的轮廓马尔可夫模型，我们寻找其他可能的驱虫 Cry 蛋白，并在该列表中鉴定出一种苏云金芽孢杆菌晶体蛋白，GenBank accession no. MF893203，我们生产并证明了该蛋白对胃肠道线虫具有毒性。这种蛋白与 Cry14Ab 有 90%的氨基酸同一性，在体外对 C. elegans、A. ceylanicum 成虫和 A. suum L4 幼虫有效。MF893203 被正式指定为 Cry14Ac。Cry14Ac 也是一种有效的体内驱虫剂，可防治仓鼠中的 A. ceylanicum 钩虫和小鼠中的肠道 A. suum。总之，我们的结果表明，Cry14Ab 和 Cry14Ac 对胃肠道线虫具有广泛的治疗用途。
