The good, the bad, and the phosphate: regulation of beneficial and detrimental plant-microbe interactions by the plant phosphate status.

Phosphate (P ) is indispensable for life on this planet. However, for sessile land plants it is poorly accessible. Therefore, plants have developed a variety of strategies for enhanced acquisition and recycling of P .

PHOSPHATE STARVATION RESPONSE transcription factors enable arbuscular mycorrhiza symbiosis.

Arbuscular mycorrhiza (AM) is a widespread symbiosis between roots of the majority of land plants and Glomeromycotina fungi. AM is important for ecosystem health and functioning as the fungi critically support plant performance by providing essential mineral nutrients, particularly the poorly accessible phosphate, in exchange for organic carbon. AM fungi colonize the inside of roots and this is promoted at low but inhibited at high plant phosphate status, while the mechanistic basis for this phosphate-dependence remained obscure.

A CCaMK-CYCLOPS-DELLA Complex Activates Transcription of RAM1 to Regulate Arbuscule Branching.

Intracellular arbuscular mycorrhiza symbiosis between plants and glomeromycotan fungi leads to formation of highly branched fungal arbuscules that release mineral nutrients to the plant host. Their development is regulated in plants by a mechanistically unresolved interplay between symbiosis, nutrient, and hormone (gibberellin) signaling. Using a positional cloning strategy and a retrotransposon insertion line, we identify two novel alleles of Lotus japonicus REDUCED ARBUSCULAR MYCORRHIZA1 (RAM1) encoding a GRAS protein.