Root-knot nematodes (Meloidogyne spp.) are parasites that attack many field crops and orchard trees, and affect both the quantity and quality of the products. A root-colonizing bacterium, Pseudomonas chlororaphis O6, possesses beneficial traits including strong nematicidal activity. To determine the molecular mechanisms involved in the nematicidal activity of P. chlororaphis O6, we constructed two mutants; one lacking hydrogen cyanide production, and a second lacking an insecticidal toxin, FitD. Root drenching with wild-type P. chlororaphis O6 cells caused juvenile mortality in vitro and in planta. Efficacy was not altered in the fitD mutant compared to the wild-type but was reduced in both bioassays for the mutant lacking hydrogen cyanide production. The reduced number of galls on tomato plants caused by the wild-type strain was comparable to that of a standard chemical nematicide. These findings suggest that hydrogen cyanide-producing root colonizers, such as P. chlororaphis O6, could be formulated as "green" nematicides that are compatible with many crops and offer agricultural sustainability.

中文翻译：

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绿假单胞菌O6产生的氰化氢表现出对根结线虫的杀线虫活性。

根结线虫（Meloidogyne spp。）是一种寄生虫，会侵袭许多大田作物和果园树，并影响产品的数量和质量。根定殖细菌绿假单胞菌O6具有有益的特性，包括强大的杀线虫活性。为了确定参与P. chlororaphis O6杀线虫活性的分子机制，我们构建了两个突变体。一种缺乏氰化氢生产，另一种缺乏杀虫毒素FitD。用野生型绿藻P6细胞进行根浸可在体外和植物体内引起幼虫死亡。fitD中的功效没有改变突变体与野生型相比，但在两种生物测定中均减少了缺乏氰化氢产生的突变体。由野生型菌株引起的番茄植株上胆汁的减少与标准化学杀线虫剂的减少相当。这些发现表明，可以将产生氰化氢的根定殖剂，例如绿假单胞菌O6配制成与许多农作物相容并具有农业可持续性的“绿色”杀线虫剂。