The Medicago SPX1/3-PHR2 network relays phosphate signaling to orchestrate root nodulation-dependent nitrogen acquisition by controlling flavonoid biosynthesis.
Wang P, Jiang F, Xue Z, Bu F, Zhu W
Plant Signaling
PubMedThe beans and peas in your garden naturally fertilize themselves by recruiting soil bacteria — and this study reveals the hidden chemical dial that controls how well that process works, opening doors to crops that need far less synthetic fertilizer.
Plants like clover and alfalfa can 'hire' bacteria to pull nitrogen from the air and deliver it to their roots — but only when conditions are right. This study found that the plant's internal phosphorus sensor controls whether it sends out the chemical invitations (flavonoids) that attract those helpful bacteria. When phosphorus is plentiful, the plant sends the invitations and gets free nitrogen; when phosphorus is scarce, it holds back.
Key Findings
The SPX1/3-PHR2 regulatory network directly controls flavonoid biosynthesis genes, linking phosphate availability to nitrogen-fixing microbe recruitment.
Plants with disrupted SPX1/3 genes showed reduced flavonoid levels in root exudates and a measurably smaller population of nitrogen-fixing bacteria, including rhizobia, in the surrounding soil.
PHR2 binds directly to the promoter regions of flavonoid biosynthetic genes, providing a molecular mechanism by which phosphate status suppresses or promotes root nodule symbiosis.
chevron_right Technical Summary
Scientists discovered a molecular switch in legume plants that links phosphorus sensing to the recruitment of nitrogen-fixing bacteria. When phosphorus is available, the SPX1/3-PHR2 network releases chemical signals (flavonoids) that attract beneficial microbes to plant roots, enabling the plant to also acquire nitrogen.
Abstract Preview
The formation of symbiotic associations with rhizospheric microbes is a key strategy by which sessile plants acquire nitrogen and phosphorus from the soil. Root exudates play a central role in shap...
open_in_new Read full abstract on PubMedAbstract copyright held by the original publisher.
Species Mentioned
Was this useful?
Chloroplast Genome Editing Eliminates Gluten Immunogenicity in Triticum aestivum
It could mean that people with celiac disease — roughly 1 in 100 worldwide — may one day safely eat bread made from real wheat, without sacrificing the taste...
Medicago truncatula, the barrelclover, strong-spined medick, barrel medic, or barrel medick, is a small annual legume native to the Mediterranean region that is used in genomic research.