Discovery of nitrate–CPK–NLP signalling in central nutrient–growth networks

5 years ago

Discovery of nitrate–CPK–NLP signalling in central nutrient–growth networks

Kevan Shokat, Hao Du, Shugo Maekawa, Marie Boudsocq, Chao Zhang, Kun-hsiang Liu, Yue Wu, Jen Sheen, Yajie Niu, Shuichi Yanagisawa, Lei Li, Mineko Konishi, Tetsuya Ishida, Hoo Sun Chung, Matthew McCormack

Nutrient signalling integrates and coordinates gene expression, metabolism and growth. However, its primary molecular mechanisms remain incompletely understood in plants and animals. Here we report unique Ca²⁺ signalling triggered by nitrate with live imaging of an ultrasensitive biosensor in Arabidopsis leaves and roots. A nitrate-sensitized and targeted functional genomic screen identifies subgroup III Ca²⁺-sensor protein kinases (CPKs) as master regulators that orchestrate primary nitrate responses. A chemical switch with the engineered mutant CPK10(M141G) circumvents embryo lethality and enables conditional analyses of cpk10 cpk30 cpk32 triple mutants to define comprehensive nitrate-associated regulatory and developmental programs. Nitrate-coupled CPK signalling phosphorylates conserved NIN-LIKE PROTEIN (NLP) transcription factors to specify the reprogramming of gene sets for downstream transcription factors, transporters, nitrogen assimilation, carbon/nitrogen metabolism, redox, signalling, hormones and proliferation. Conditional cpk10 cpk30 cpk32 and nlp7 mutants similarly impair nitrate-stimulated system-wide shoot growth and root establishment. The nutrient-coupled Ca²⁺ signalling network integrates transcriptome and cellular metabolism with shoot–root coordination and developmental plasticity in shaping organ biomass and architecture.

Publisher URL: http://dx.doi.org/10.1038/nature22077

DOI: 10.1038/nature22077