Effects of phosphate deficiency and sugars on expression of rab18 in Arabidopsis: hexokinase-dependent and okadaic acid-sensitive transduction of the sugar signal
2002 (English)In: Biochimica et Biophysica Acta, Gene Structure and Expression, ISSN 0167-4781, E-ISSN 1879-2634, Vol. 1579, no 1, 43-49 p.Article in journal (Refereed) Published
The lack of phosphorus in the nutrient medium increased the expression of rab18, an abscisic acid (ABA)-responsive gene, in leaves of Arabidopsis thaliana. The expression of this gene was also upregulated after feeding the excised leaves with D-mannose and sucrose for both wild-type (wt) and aba1 (ABA-deficient) mutant plants. For aba1 mutants, both the phosphate deficiency and sugar effects on rab18 were weaker than in wt plants, suggesting possible involvement of both ABA-dependent and ABA-independent components in signalling. Transgenic Arabidopsis plants with increased hexokinase (HXK) expression had a much higher sucrose-dependent level of rab18 mRNA, implying the HXK involvement in sensing/transmitting the sugar signal. Sucrose-related induction of rab18 was completely inhibited by okadaic acid (OKA), suggesting the involvement of specific protein phosphatase(s) in transduction of the sugar signal. The results suggest that rab18 is regulated via interaction of a plethora of signals, including ABA, sugar and phosphate deficiency, and that the sugar effect is transmitted via a HXK-pathway, involving OKA-sensitive component(s). The findings prompt caution in linking the expression of rab18 solely to ABA signalling. (C) 2002 Elsevier Science B.V. All rights reserved.
Place, publisher, year, edition, pages
2002. Vol. 1579, no 1, 43-49 p.
aba mutant, gene expression, mannose, phosphate stress, sucrose
IdentifiersURN: urn:nbn:se:umu:diva-44730ISI: 000178980800006OAI: oai:DiVA.org:umu-44730DiVA: diva2:426363