NODULE INCEPTION Recruits the Lateral Root Developmental Program for Symbiotic Nodule Organogenesis in Medicago truncatula

To overcome nitrogen deficiencies in the soil, legumes enter symbioses with rhizobial bacteria that convert atmospheric nitrogen into ammonium. Rhizobia are accommodated as endosymbionts within lateral root organs called nodules that initiate from the inner layers of Medicago truncatula roots in response to rhizobial perception. In contrast, lateral roots emerge from predefined founder cells as an adaptive response to environmental stimuli, including water and nutrient availability. CYTOKININ RESPONSE 1 (CRE1)-mediated signaling in the pericycle and in the cortex is necessary and sufficient for nodulation, whereas cytokinin is antagonistic to lateral root development, with cre1 showing increased lateral root emergence and decreased nodulation. To better understand the relatedness between nodule and lateral root development, we undertook a comparative analysis of these two root developmental programs. Here, we demonstrate that despite differential induction, lateral roots and nodules share overlapping developmental programs, with mutants in LOB-DOMAIN PROTEIN 16 (LBD16) showing equivalent defects in nodule and lateral root initiation. The cytokinin-inducible transcription factor NODULE INCEPTION (NIN) allows induction of this program during nodulation through activation of LBD16 that promotes auxin biosynthesis via transcriptional induction of STYLISH (STY) and YUCCAs (YUC). We conclude that cytokinin facilitates local auxin accumulation through NIN promotion of LBD16, which activates a nodule developmental program overlapping with that induced during lateral root initiation.

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Author Schiessl, Katharina
Last Updated November 20, 2019, 16:52 (UTC)
Created November 4, 2019, 17:56 (UTC)
Article Host Type publisher
Article Is Open Access true
Article License Type cc-by
Article Version Type publishedVersion
Citation Report https://scite.ai/reports/10.1016/j.cub.2019.09.005
DOI 10.1016/j.cub.2019.09.005
Date Last Updated 2019-10-20T20:00:15.561505
Evidence open (via page says license)
Funder code(s) Bill and Melinda Gates Foundation (OPP1028264); Biotechnology and Biological Sciences Research Council (BB/K003712/1); Nederlandse Organisatie voor Wetenschappelijk Onderzoek (VENI863-15-010); National Science Foundation (DBI 0703285, IOS-1127155); Noble Research Institute (); Gatsby Foundation (GAT3395/GLH)
Journal Is Open Access false
Open Access Status hybrid
PDF URL http://www.cell.com/article/S0960982219311650/pdf
Publisher URL https://doi.org/10.1016/j.cub.2019.09.005