The characteristic high sulfate content in Brassica oleracea is controlled by the expression and activity of sulfate transporters.
The uptake and distribution of sulfate in BRASSICA OLERACEA, a species characterised by its high sulfate content in root and shoot, are coordinated and adjusted to the sulfur requirement for growth, even at external sulfate concentrations close to the K (m) value of the high-affinity sulfate transporters. Plants were able to grow normally and maintain a high sulfur content when grown at 5 or 10 microM sulfate in the root environment. Abundance of mRNAs for the high affinity sulfate transporters, BolSultr1;1 and BolSultr1;2, were enhanced at <or= 25 microM sulfate, and this was accompanied with an up to three-fold increase in the sulfate uptake capacity, whereas sulfate, organic sulfur, and thiol contents were only slightly affected. Upon sulfate deprivation, there was a much greater induction of the sulfate transporters, BolSultr1;1, BolSultr1;2, BolSultr1;3, BolSultr2;1, and BolSultr4;1, whilst the sulfate uptake capacity was only increased up to four-fold. Plant growth and shoot to root biomass allocation were affected only upon sulfate-deprivation and not at low external sulfate concentrations. From the current results it is suggested that the internal sulfate concentration may act as a determining factor in the regulation of activity and expression of sulfate transporters, and of shoot to root biomass allocation in B. OLERACEA.
Koralewska
A
A
Laboratory of Plant Physiology, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands.
Posthumus
F S
FS
Stuiver
C E E
CE
Buchner
P
P
Hawkesford
M J
MJ
De Kok
L J
LJ
D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018533:Biomass; D001937:Brassica / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007700:Kinetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism* / Q000494:pharmacology; D052584:Xylem / Q000187:drug effects / Q000378:metabolism
D027321:Anion Transport Proteins; D010940:Plant Proteins; D013431:Sulfates