Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA.
Nat Genet. 2011 May;43(5):421-7. doi: 10.1038/ng.798. Epub 2011 Mar 27.
Glycerol-3-phosphate (G3P) is an important metabolite that contributes to the growth and disease-related physiologies of prokaryotes, plants, animals and humans alike. Here we show that G3P serves as the inducer of an important form of broad-spectrum immunity in plants, termed systemic acquired resistance (SAR). SAR is induced upon primary infection and protects distal tissues from secondary infections. Genetic mutants defective in G3P biosynthesis cannot induce SAR but can be rescued when G3P is supplied exogenously. Radioactive tracer experiments show that a G3P derivative is translocated to distal tissues, and this requires the lipid transfer protein, DIR1. Conversely, G3P is required for the translocation of DIR1 to distal tissues, which occurs through the symplast. These observations, along with the fact that dir1 plants accumulate reduced levels of G3P in their petiole exudates, suggest that the cooperative interaction of DIR1 and G3P orchestrates the induction of SAR in plants.
甘油-3-磷酸（G3P）是一种重要的代谢物，有助于原核生物、植物、动物和人类的生长和疾病相关生理过程。在这里，我们表明 G3P 是植物中一种重要的广谱免疫形式——系统性获得抗性（SAR）的诱导剂。SAR 在初次感染时被诱导，并保护远端组织免受二次感染。在 G3P 生物合成中发生突变的遗传突变体不能诱导 SAR，但当外源性提供 G3P 时可以被挽救。放射性示踪剂实验表明，G3P 的一种衍生物被转运到远端组织，这需要脂转移蛋白 DIR1。相反，G3P 是 DIR1 向远端组织转运所必需的，这是通过质外体发生的。这些观察结果，以及 dir1 植物在叶柄分泌物中积累的 G3P 水平降低的事实，表明 DIR1 和 G3P 的合作相互作用协调了植物中 SAR 的诱导。
