PMID- 12624766
OWN - NLM
STAT- MEDLINE
DCOM- 20030620
LR  - 20161124
IS  - 0032-0935 (Print)
IS  - 0032-0935 (Linking)
VI  - 216
IP  - 5
DP  - 2003 Mar
TI  - Integrating diel starch metabolism with the circadian and environmental 
      regulation of Crassulacean acid metabolism in Mesembryanthemum crystallinum.
PG  - 789-97
AB  - The diel (24-h) Crassulacean acid metabolism (CAM) cycle in Mesembryanthemum 
      crystallinum (L.) requires rhythmic patterns of transitory starch degradation to 
      produce carbon skeletons for phospho enolpyruvate (PEP) synthesis during the 
      nocturnal Phase I, when PEP carboxylase (PEPc) mediates CO(2) fixation. Under a 
      normal light-dark cycle, nocturnal malate accumulation and nocturnal CO(2) uptake 
      were observed for CAM-induced, but not C(3), M. crystallinum. In both C(3) and 
      CAM plants, transcripts encoding beta-amylase and starch phosphorylase 
      accumulated during the afternoon and declined nocturnally. Under a continuous 
      light regime, ribulose-1,5-bisphosphate carboxylase/oxygenase activity remained 
      co-ordinated with the CAM phases, and circadian abundance patterns were observed 
      for transcripts encoding starch degradative enzymes. Despite circadian PEPc 
      kinase expression, the accumulation of vacuolar malate ceased under continuous 
      light. Exposure to CO(2)-free air for 24 h inhibited starch accumulation over the 
      photoperiod, but re-fixation of respiratory CO(2) resulted in the overnight 
      accumulation of malate to levels comparable to those of control plants. Upon 
      return to normal air, the depleted starch concentration led to stoichiometric 
      decreases in Phase-I CO(2) uptake and malate accumulation. The up-regulation of 
      PEPc kinase transcripts under these conditions was ineffective at sustaining 
      Phase-I CO(2) uptake under starch-limited conditions. We conclude that starch 
      turnover regulates and limits carbon flux through the diel CAM cycle.
FAU - Dodd, Antony N
AU  - Dodd AN
AD  - Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, 
      CB2 3EA, UK. antony.dodd@plantsci.cam.ac.uk
FAU - Griffiths, Howard
AU  - Griffiths H
FAU - Taybi, Tahar
AU  - Taybi T
FAU - Cushman, John C
AU  - Cushman JC
FAU - Borland, Anne M
AU  - Borland AM
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20021119
PL  - Germany
TA  - Planta
JT  - Planta
JID - 1250576
RN  - 0 (Malates)
RN  - 0 (Photosynthetic Reaction Center Complex Proteins)
RN  - 142M471B3J (Carbon Dioxide)
RN  - 817L1N4CKP (malic acid)
RN  - 9005-25-8 (Starch)
RN  - EC 2.4.1.- (Starch Phosphorylase)
RN  - EC 3.2.1.2 (beta-Amylase)
RN  - EC 4.1.1.31 (Phosphoenolpyruvate Carboxylase)
RN  - EC 4.1.1.39 (Ribulose-Bisphosphate Carboxylase)
SB  - IM
MH  - Carbon Dioxide/metabolism
MH  - Circadian Rhythm/*physiology
MH  - Crassulaceae/genetics/*metabolism/radiation effects
MH  - Gene Expression Regulation, Plant/radiation effects
MH  - Light
MH  - Malates/metabolism
MH  - Mesembryanthemum/genetics/*metabolism/radiation effects
MH  - Phosphoenolpyruvate Carboxylase/metabolism
MH  - Photoperiod
MH  - Photosynthetic Reaction Center Complex 
      Proteins/classification/*metabolism/radiation effects
MH  - Plant Leaves/metabolism
MH  - Ribulose-Bisphosphate Carboxylase/metabolism
MH  - Starch/*metabolism
MH  - Starch Phosphorylase/metabolism
MH  - beta-Amylase/metabolism
EDAT- 2003/03/08 04:00
MHDA- 2003/06/21 05:00
CRDT- 2003/03/08 04:00
PHST- 2002/06/01 00:00 [received]
PHST- 2002/10/07 00:00 [accepted]
PHST- 2003/03/08 04:00 [pubmed]
PHST- 2003/06/21 05:00 [medline]
PHST- 2003/03/08 04:00 [entrez]
AID - 10.1007/s00425-002-0930-2 [doi]
PST - ppublish
SO  - Planta. 2003 Mar;216(5):789-97. doi: 10.1007/s00425-002-0930-2. Epub 2002 Nov 19.