Glycerol-3-phosphate is a critical mobile inducer of systemic immunity in plants

Authors: CHANDRA, B - University Of Kentucky; YE, XIA - University Of Kentucky; MANDAL, MH - University Of Kentucky; YU, K - University Of Kentucky; SEKINE, K-T - University Of Kentucky; GAO, Q - University Of Kentucky; SELOTE, D - University Of Kentucky; HU, Y - University Of Kentucky; STROMBERG, A - University Of Kentucky; Navarre, Duroy - Roy; KACHROO, A - University Of Kentucky; KACHROO, P - University Of Kentucky

Submitted to: Nature Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2011
Publication Date: 3/27/2011
Citation: Chandra, B., Ye, X., Mandal, M., Yu, K., Sekine, K., Gao, Q., Selote, D., Hu, Y., Stromberg, A., Navarre, D.A., Kachroo, A., Kachroo, P. 2011. Glycerol-3-phosphate is a critical mobile inducer of systemic immunity in plants.. Nature Genetics. 43:421-427. DOI 0110.1038/ng.798..

Interpretive Summary: Systemic immunity is a widespread phenomenom in plants that activates a broad spectrum resistance to pathogens throughout the plant and has been shown to be effective against bacteria, fungi, oomycetes and viruses. This is a natural defense mechanism that once more completely understood could be more fully utilized to improve disease resistance in plants, protect yields and reduce costly pesticide treatments. Systemic immunity can be activated by treatment with elicitors or naturally in response to pathogens. This work shows that glycerol-3-phosphate places a critical role in the development of systemic immunity at an early timepoint and suggests a role for this compound in developing resistance in distal parts of the plants not directly challenged by pathogens. This provides insight into the key question of how non-infected parts of plants develop resistance in response to a localized infection.

Technical Abstract: 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.