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Accumulation of 2‐ C ‐methyl‐ d ‐erythritol 2,4‐cyclodiphosphate in illuminated plant leaves at supraoptimal temperatures reveals a bottleneck of the prokaryotic methylerythritol 4‐phosphate pathway of isoprenoid biosynthesis
Author(s) -
RIVASSEAU CORINNE,
SEEMANN MYRIAM,
BOISSON ANNEMARIE,
STREB PETER,
GOUT ELISABETH,
DOUCE ROLAND,
ROHMER MICHEL,
BLIGNY RICHARD
Publication year - 2009
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2008.01903.x
Subject(s) - spinacia , chemistry , chloroplast , atp synthase , photosynthesis , phosphate , biochemistry , pentose phosphate pathway , terpenoid , ethylene , metabolism , botany , stereochemistry , enzyme , biology , glycolysis , gene , catalysis
Metabolic profiling using phosphorus nuclear magnetic resonance ( 31 P‐NMR) revealed that the leaves of different herbs and trees accumulate 2‐ C ‐methyl‐ d ‐erythritol 2,4‐cyclodiphosphate (MEcDP), an intermediate of the methylerythritol 4‐phosphate (MEP) pathway, during bright and hot days. In spinach ( Spinacia oleracea L.) leaves, its accumulation closely depended on irradiance and temperature. MEcDP was the only 31 P‐NMR‐detected MEP pathway intermediate. It remained in chloroplasts and was a sink for phosphate. The accumulation of MEcDP suggested that its conversion rate into 4‐hydroxy‐3‐methylbut‐2‐enyl diphosphate, catalysed by ( E )‐4‐hydroxy‐3‐methylbut‐2‐enyl diphosphate synthase (GcpE), was limiting under oxidative stress. Indeed, O 2 and ROS produced by photosynthesis damage this O 2 ‐hypersensitive [4Fe‐4S]‐protein. Nevertheless, as isoprenoid synthesis was not inhibited, damages were supposed to be continuously repaired. On the contrary, in the presence of cadmium that reinforced MEcDP accumulation, the MEP pathway was blocked. In vitro studies showed that Cd 2+ does not react directly with fully assembled GcpE, but interferes with its reconstitution from recombinant GcpE apoprotein and prosthetic group. Our results suggest that MEcDP accumulation in leaves may originate from both GcpE sensitivity to oxidative environment and limitations of its repair. We propose a model wherein GcpE turnover represents a bottleneck of the MEP pathway in plant leaves simultaneously exposed to high irradiance and hot temperature.