TY - JOUR
T1 - Genes controlling legume nodule numbers affect phenotypic plasticity responses to nitrogen in the presence and absence of rhizobia
AU - Goh, Chooi Hua
AU - Nicotra, Adrienne B.
AU - Mathesius, Ulrike
N1 - Publisher Copyright:
© 2018 John Wiley & Sons Ltd
PY - 2019/5
Y1 - 2019/5
N2 - We investigated the role of three autoregulation of nodulation (AON) genes in regulating of root and shoot phenotypes when responding to changing nitrogen availability in the model legume, Medicago truncatula. These genes, RDN1-1 (ROOT DETERMINED NODULATION1-1), SUNN (SUPER NUMERIC NODULES), and LSS (LIKE SUNN SUPERNODULAOR), act in a systemic signalling pathway that limits nodule numbers. This pathway is also influenced by nitrogen availability, but it is not well known if AON genes control root and shoot phenotypes other than nodule numbers in response to nitrogen. We conducted a controlled glasshouse experiment to compare root and shoot phenotypes of mutants and wild type plants treated with four nitrate concentrations. All AON mutants showed altered rhizobia-independent phenotypes, including biomass allocation, lateral root length, lateral root density, and root length ratio. In response to nitrogen, uninoculated AON mutants were less plastic than the wild type in controlling root mass ratio, root length ratio, and lateral root length. This suggests that AON genes control nodulation-independent root architecture phenotypes in response to nitrogen. The phenotypic differences between wild type and AON mutants were exacerbated by the presence of nodules, pointing to resource competition as an additional mechanism affecting root and shoot responses to nitrogen.
AB - We investigated the role of three autoregulation of nodulation (AON) genes in regulating of root and shoot phenotypes when responding to changing nitrogen availability in the model legume, Medicago truncatula. These genes, RDN1-1 (ROOT DETERMINED NODULATION1-1), SUNN (SUPER NUMERIC NODULES), and LSS (LIKE SUNN SUPERNODULAOR), act in a systemic signalling pathway that limits nodule numbers. This pathway is also influenced by nitrogen availability, but it is not well known if AON genes control root and shoot phenotypes other than nodule numbers in response to nitrogen. We conducted a controlled glasshouse experiment to compare root and shoot phenotypes of mutants and wild type plants treated with four nitrate concentrations. All AON mutants showed altered rhizobia-independent phenotypes, including biomass allocation, lateral root length, lateral root density, and root length ratio. In response to nitrogen, uninoculated AON mutants were less plastic than the wild type in controlling root mass ratio, root length ratio, and lateral root length. This suggests that AON genes control nodulation-independent root architecture phenotypes in response to nitrogen. The phenotypic differences between wild type and AON mutants were exacerbated by the presence of nodules, pointing to resource competition as an additional mechanism affecting root and shoot responses to nitrogen.
KW - autoregulation of nodulation
KW - biomass allocation
KW - lateral root development
KW - legume
KW - nitrogen responses
KW - phenotypic plasticity
KW - rhizobia
KW - root architecture
UR - http://www.scopus.com/inward/record.url?scp=85058858802&partnerID=8YFLogxK
U2 - 10.1111/pce.13498
DO - 10.1111/pce.13498
M3 - Article
SN - 0140-7791
VL - 42
SP - 1747
EP - 1757
JO - Plant, Cell and Environment
JF - Plant, Cell and Environment
IS - 5
ER -