Pacheco Sabino, Gómez Isabel, Chiñas Marcos, Sánchez Jorge, Soberón Mario, Bravo Alejandra
Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico.
Front Microbiol. 2021 Nov 2;12:758314. doi: 10.3389/fmicb.2021.758314. eCollection 2021.
() are soil ubiquitous bacteria. They produce a great variability of insecticidal proteins, where certain of these toxins are used worldwide for pest control. Through their adaptation to diverse ecosystems, certain strains have acquired genetic mobile elements by horizontal transfer, harboring genes that encode for different virulent factors and pesticidal proteins (PP). Genomic characterization of strains provides a valuable source of PP with potential biotechnological applications for pest control. In this work, we have sequenced the complete genome of the bacterium GR007 strain that is toxic to and larvae. Four replicons (one circular chromosome and three megaplasmids) were identified. The two largest megaplasmids (pGR340 and pGR157) contain multiple genes that codify for pesticidal proteins: 10 genes (, , , , , , , , , and ), two genes ( and ), two binary toxin genes (), five genes that codify for insecticidal toxin components (Tc's), and a truncated -like gene. In addition, genes that codify for several virulent factors were also found in this strain. Proteomic analysis of the parasporal crystals of GR007 revealed that they are composed of eight Cry proteins. Further cloning of these genes for their individual expression in acrystalliferous strain, by means of their own intrinsic promoter showed expression of seven Cry proteins. These proteins display differential toxicity against and larvae, where Cry1Bb showed to be the most active protein against larvae and Cry1Ka the most active protein against larvae.
（）是土壤中普遍存在的细菌。它们产生多种杀虫蛋白，其中某些毒素在全球范围内用于害虫防治。通过适应不同的生态系统，某些菌株通过水平转移获得了遗传移动元件，携带编码不同致病因子和杀虫蛋白（PP）的基因。菌株的基因组特征为害虫防治提供了具有潜在生物技术应用价值的PP来源。在这项工作中，我们对GR007菌株进行了全基因组测序，该菌株对和幼虫有毒。鉴定出四个复制子（一个环形染色体和三个大质粒）。两个最大的大质粒（pGR340和pGR157）包含多个编码杀虫蛋白的基因：10个基因（，，，，，，，，，和），两个基因（和），两个二元毒素基因（），五个编码杀虫毒素成分（Tc's）的基因，以及一个截短的样基因。此外，在该菌株中还发现了编码几种致病因子的基因。GR007芽孢伴孢晶体的蛋白质组分析表明，它们由八种Cry蛋白组成。通过其自身的内在启动子，将这些基因进一步克隆到无晶体菌株中进行单独表达，结果显示表达了七种Cry蛋白。这些蛋白对和幼虫表现出不同的毒性，其中Cry1Bb对幼虫最具活性，Cry1Ka对幼虫最具活性。
