Transition from a maternal to external nitrogen source in maize seedlings.
Maximizing NO3-uptake during seedling development is important as it has a major influence on plant growth and yield. However, little is known about the processes leading to, and involved in, the initiation of root NO3-uptake capacity in developing seedlings. This study examines the physiological processes involved in root NO3-uptake and metabolism, to gain an understanding of how the NO3-uptake system responds to meet demand as maize seedlings transition from seed N use to external N capture. The concentrations of seed-derived free amino acids within root and shoot tissues are initially high, but decrease rapidly until stabilizing eight days after imbibition (DAI). Similarly, shoot N% decreases, but does not stabilize until 12-13 DAI. Following the decrease in free amino acid concentrations, root NO3-uptake capacity increases until shoot N% stabilizes. The increase in root NO3-uptake capacity corresponds with a rapid rise in transcript levels of putative NO3-transporters, ZmNRT2.1 and ZmNRT2.2. The processes underlying the increase in root NO3-uptake capacity to meet N demand provide an insight into the processes controlling N uptake.
Australian Centre for Plant Functional Genomics, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.|School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.
Kasra
K
Sabermanesh
Australian Centre for Plant Functional Genomics, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.|School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.
Luke R
LR
Holtham
Australian Centre for Plant Functional Genomics, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.|School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.
Jessey
J
George
Australian Centre for Plant Functional Genomics, School of BioSciences, University of Melbourne, Parkville, Vic. 3010, Australia.|Metabolomics Australia, School of BioSciences, University of Melbourne, Vic. 3010, Australia.
Ute
U
Roessner
Metabolomics Australia, School of BioSciences, University of Melbourne, Vic. 3010, Australia.
Berin A
BA
Boughton
Australian Centre for Plant Functional Genomics, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.|School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.
Sigrid
S
Heuer
Australian Centre for Plant Functional Genomics, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.|King Abdullah University of Science and Technology, Center for Desert Agriculture, Thuwal 23955-6900, Kingdom of Saudi Arabia.
Mark
M
Tester
Australian Centre for Plant Functional Genomics, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.|School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.
Darren C
DC
Plett
Australian Centre for Plant Functional Genomics, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.|School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, SA 5064, Australia.|The Australian Plant Phenomics Facility, The Plant Accelerator, Waite Campus, The University of Adelaide, Adelaide, SA 5064, Australia.
Trevor P
TP
Garnett
D000596:Amino Acids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D050901:Nitrate Reductase / Q000235:genetics / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D003313:Zea mays / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
D000596:Amino Acids; D009566:Nitrates; D010940:Plant Proteins; D012333:RNA, Messenger; D050901:Nitrate Reductase; D009584:Nitrogen