Premium
The diversion of 2‐ C ‐methyl‐ d ‐erythritol‐2,4‐cyclodiphosphate from the 2‐ C ‐methyl‐ d ‐erythritol 4‐phosphate pathway to hemiterpene glycosides mediates stress responses in Arabidopsis thaliana
Author(s) -
GonzálezCabanelas Diego,
Wright Louwrance P.,
Paetz Christian,
Onkokesung Nawaporn,
Gershenzon Jonathan,
RodríguezConcepción Manuel,
Phillips Michael A.
Publication year - 2015
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12798
Subject(s) - erythritol , biochemistry , mutant , chemistry , stereochemistry , metabolic pathway , arabidopsis , metabolism , biology , gene
Summary 2‐ C ‐Methyl‐ d ‐erythritol‐2,4‐cyclodiphosphate ( ME c DP ) is an intermediate of the plastid‐localized 2‐ C ‐methyl‐ d ‐erythritol‐4‐phosphate ( MEP ) pathway which supplies isoprenoid precursors for photosynthetic pigments, redox co‐factor side chains, plant volatiles, and phytohormones. The Arabidopsis hds‐3 mutant, defective in the 1‐hydroxy‐2‐methyl‐2‐( E )‐butenyl‐4‐diphosphate synthase step of the MEP pathway, accumulates its substrate ME c DP as well as the free tetraol 2‐ C ‐methyl‐ d ‐erythritol ( ME ) and glucosylated ME metabolites, a metabolic diversion also occurring in wild type plants. ME c DP dephosphorylation to the free tetraol precedes glucosylation, a process which likely takes place in the cytosol. Other MEP pathway intermediates were not affected in hds‐3 . Isotopic labeling, dark treatment, and inhibitor studies indicate that a second pool of ME c DP metabolically isolated from the main pathway is the source of a signal which activates salicylic acid induced defense responses before its conversion to hemiterpene glycosides. The hds‐3 mutant also showed enhanced resistance to the phloem‐feeding aphid Brevicoryne brassicae due to its constitutively activated defense response. However, this ME c DP ‐mediated defense response is developmentally dependent and is repressed in emerging seedlings. ME c DP and ME exogenously applied to adult leaves mimics many of the gene induction effects seen in the hds‐3 mutant. In conclusion, we have identified a metabolic shunt from the central MEP pathway that diverts ME c DP to hemiterpene glycosides via ME , a process linked to balancing plant responses to biotic stress.