Dissecting local and systemic circadian signals in nodulation

Dissecting local and systemic circadian signals in nodulation

Plant Biology

Yu Yan

Miriam L. Gifford, Yinying Yuan

Legumes form root nodules that house nitrogen-fixing bacteria. The circadian clock gene *LHY* has been linked to nodulation in *Medicago truncatula*, but it remains unclear whether its effects depend on the root, the shoot, or both. This project uses reciprocal micrografting between wild-type and *lhy* mutant seedlings to separate the contributions of root and shoot genotype. A complementary split-root experiment tests whether nitrogen supplied to one root compartment affects nodulation in the other. So far, a micrografting workflow has been established and the split-root setup has been piloted. Planned analyses will compare nodule numbers and use timed RT–qPCR to measure the relative abundance of *LHY* and selected nodulation-related transcripts. Understanding how the plant clock regulates nodulation could inform future efforts to improve symbiotic nitrogen fixation in legume crops.

Medicago truncatula, nodulation, circadian clock, LHY, rhizobia, symbiotic nitrogen fixation, reciprocal micrografting, split-root experiment