State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China.
Pest Manag Sci. 2021 Mar;77(3):1465-1475. doi: 10.1002/ps.6165. Epub 2020 Nov 12.
Improvements in the virulence of the fungal pathogen Metarhizium acridum can crucially promote its efficacy to control locusts and grasshoppers. The polysaccharide components of the cell wall remarkably contribute to fungal virulence.
Here we found that M. acridum lacked the gene families of glycerate-3-kinase (GLYK) as the synthesis enzymes of saccharides. We then generated mutants by introducing the GLYK gene from the host-generalist M. robertsii into the host-specialist M. acridum. Consequently, compared with the wild-type strain, the mutant strain (Ma::MrGLYK) increased the level of phospho-6-fructose in mycelia, the length and density of the mannan fibril layer on the cell wall. The mutant strains increased the mannan fibril in the cell wall and resistance to heat stress. Further transcriptome analysis showed that compared with the wild-type strain, topical infection of Ma::MrGLYK strain induced higher expression of genes such as pattern-recognition proteins, serine protease, and CYP450s in locusts, while reduced the expression of antimicrobial peptide and phenoloxidase activity. Moreover, topical infection and injection of Ma::MrGLYK significantly increased the mortality and shortened the lifespan of locusts compared with wild-type M. acridum.
Our study highlighted the application potential of the novel genetically modified fungal mutant of the host-specialist M. acridum as a biocontrol agent against locust plagues. © 2020 Society of Chemical Industry.
真菌病原体绿僵菌毒力的提高可以显著提高其防治蝗虫和蚱蜢的功效。细胞壁的多糖成分对真菌毒力有重要贡献。
我们发现绿僵菌缺乏甘油酸-3-激酶（GLYK）基因家族，作为糖的合成酶。然后，我们通过将来自宿主广食性的绿僵菌的 GLYK 基因引入宿主专化性的绿僵菌中来产生突变体。因此，与野生型菌株相比，突变菌株（Ma::MrGLYK）增加了菌丝体中磷酸果糖-6 的水平，细胞壁上甘露聚糖纤维层的长度和密度。突变株增加了细胞壁中的甘露聚糖纤维和耐热性。进一步的转录组分析表明，与野生型菌株相比，Ma::MrGLYK 菌株的局部感染诱导了蝗虫中模式识别蛋白、丝氨酸蛋白酶和 CYP450s 等基因的更高表达，同时降低了抗菌肽和酚氧化酶活性的表达。此外，与野生型绿僵菌相比，Ma::MrGLYK 的局部感染和注射显著增加了蝗虫的死亡率并缩短了其寿命。
我们的研究强调了新型宿主专化性绿僵菌遗传修饰真菌突变体作为防治蝗虫灾害的生物防治剂的应用潜力。© 2020 化学工业协会。
