Molecular physiology reveals ammonium uptake and related gene expression in the seagrass Zostera muelleri.
Seagrasses are important marine foundation species, which are presently threatened by coastal development and global change worldwide. The molecular mechanisms that drive seagrass responses to anthropogenic stresses, including elevated levels of nutrients such as ammonium, remains poorly understood. Despite the evidence that seagrasses can assimilate ammonium by using glutamine synthetase (GS)/glutamate synthase (glutamine-oxoglutarate amidotransferase or GOGAT) cycle, the regulation of this fundamental metabolic pathway has never been studied at the gene expression level in seagrasses so far. Here, we combine (i) reverse transcription quantitative real-time PCR (RT-qPCR) to measure expression of key genes involved in the GS/GOGAT cycle, and (ii) stable isotope labelling and mass spectrometry to investigate15N-ammonium assimilation in the widespread Australian species Zostera muelleri subsp. capricorni (Z. muelleri). We demonstrate that exposure to a pulse of ammonium in seawater can induce changes in GS gene expression of Z. muelleri, and further correlate these changes in gene expression with15N-ammonium uptake rate in above- and below-ground tissue.
Climate Change Cluster, University of Technology Sydney, New South Wales 2007, Australia. Electronic address: mathieu.pernice@uts.edu.au.
Mathieu
M
Pernice
Climate Change Cluster, University of Technology Sydney, New South Wales 2007, Australia; Faculty of Environmental Management, Prince of Songkhla University, PO Box 50, Kor-Hong, Hatyai 90112, Thailand.
Sutinee
S
Sinutok
Climate Change Cluster, University of Technology Sydney, New South Wales 2007, Australia.
Gaurav
G
Sablok
Climate Change Cluster, University of Technology Sydney, New South Wales 2007, Australia.
Audrey S
AS
Commault
Climate Change Cluster, University of Technology Sydney, New South Wales 2007, Australia.
Martin
M
Schliep
Climate Change Cluster, University of Technology Sydney, New South Wales 2007, Australia; School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University, Victoria 3125, Australia.
Peter I
PI
Macreadie
TropWATER - Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, PO Box 6811, Cairns, Queensland 4870, Australia.
Michael A
MA
Rasheed
Climate Change Cluster, University of Technology Sydney, New South Wales 2007, Australia.
Peter J
PJ
Ralph
D064751:Ammonium Compounds / Q000378:metabolism*; D015870:Gene Expression; D005970:Glutamate Synthase / Q000235:genetics / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D035962:Zosteraceae / Q000235:genetics* / Q000378:metabolism
D064751:Ammonium Compounds; D010940:Plant Proteins; D014874:Water Pollutants, Chemical; D005970:Glutamate Synthase; D005974:Glutamate-Ammonia Ligase
Isotope; Molecular physiology; Nitrogen; Nutrients; RT-qPCR; Seagrass