Conserved and Divergent: Salicylic Acid Biosynthesis and Signaling Pathways across the Plant Kingdom.
Liu Y, Wu M, Li X, Zhang Y
Summary
PubMedPlants deploy a hormone called salicylic acid to defend against disease-causing pathogens, but different plant groups have evolved distinct strategies to produce it. Recent discoveries reveal a widespread pathway used by most seed plants, while another pathway emerged specifically in plant families including cabbage and mustard. Understanding these evolutionary differences could enable scientists to engineer more disease-resistant crops.
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Key Findings
Salicylic acid modulates plant immune responses by amplifying defenses against biotrophic and hemibiotrophic pathogens
Two distinct SA biosynthesis pathways exist: the isochorismate (ICS) pathway specific to the Brassicales order, and a phenylalanine-derived pathway widespread across seed plants
NPR proteins function as SA receptors that activate downstream signaling pathways conferring pathogen immunity
Original Abstract
Salicylic acid (SA) is a pivotal plant hormone that modulates immune responses in a pathogen lifestyle-dependent manner, typically amplifying defenses against biotrophic and hemibiotrophic pathogens. Foundational research in Arabidopsis established a paradigm for SA biology, elucidating the isochorismate (ICS) pathway for SA biosynthesis, the mechanisms regulating SA levels, the role of NPR proteins as SA receptors, and the downstream signaling pathways that confer immunity. However, recent studies in species like Nicotiana benthamiana and rice have revealed a complete phenylalanine-derived SA biosynthesis pathway that is widespread among seed plants. In contrast, the ICS pathway appears to be a recent evolutionary innovation specific to the Brassicales order. This review synthesizes the established knowledge of SA in Arabidopsis, discusses insights into the alternative pathway and the evolution of SA biosynthesis and signaling across diverse plants, and identifies key outstanding questions for future research.
This connects to 11 other discoveries — 3 species, 3 topics, 5 related articles
Species Mentioned
Arabidopsis (rockcress) is a genus of small flowering plants in the cabbage and mustard family, Brassicaceae. Arabidopsis species are native to temperate and subarctic Eurasia and North America, North Africa, and the mountains of eastern tropical Africa. This genus is of great interest since it c...
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