Phosphorylation of D-allose by hexokinase involved in regulation of OsABF1 expression for growth inhibition in Oryza sativa L

Planta. 2013 May;237(5):1379-91. doi: 10.1007/s00425-013-1853-9. Epub 2013 Feb 9.


We previously reported that a rare sugar D-allose, which is the D-glucose epimer at C3, inhibits the gibberellin-dependent responses such as elongation of the second leaf sheath and induction of α-amylase in embryo-less half seeds in rice (Fukumoto et al. 2011). D-Allose suppresses expressions of gibberellin-responsive genes downstream of SLR1 protein in the gibberellin-signaling through hexokinase (HXK)-dependent pathway. In this study, we discovered that D-allose induced expression of ABA-related genes including OsNCED1-3 and OsABA8ox1-3 in rice. Interestingly, D-allose also up-regulated expression of OsABF1, encoding a conserved bZIP transcription factor in ABA signaling, in rice. The D-allose-induced expression of OsABF1 was diminished by a hexokinase inhibitor, D-mannoheptulose (MNH). Consistently, D-allose also inhibited Arabidopsis growth, but failed to trigger growth retardation in the glucose-insensitive2 (gin2) mutant, which is a loss-of-function mutant of the glucose sensor AtHXK1. D-Allose activated AtABI5 expression in transgenic gin2 over-expressing wild-type AtHXK1 but not in gin2 over-expressing the catalytic mutant AtHXK1(S177A), indicating that the D-allose phosphorylation by HXK to D-allose 6-phosphate (A6P) is the first step for the up-regulation of AtABI5 gene expression as well as D-allose-induced growth inhibition. Moreover, overexpression of OsABF1 showed increased sensitivity to D-allose in rice. These findings indicated that the phosphorylation of D-allose at C6 by hexokinase is essential and OsABF1 is involved in the signal transduction for D-allose-induced growth inhibition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Gene Expression Regulation, Plant / drug effects
  • Glucose / metabolism*
  • Glucose / pharmacology*
  • Hexokinase / genetics
  • Hexokinase / metabolism*
  • Oryza / drug effects
  • Oryza / genetics
  • Oryza / metabolism*
  • Phosphorylation
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*


  • Plant Proteins
  • allose
  • Hexokinase
  • Glucose