Involvement of Arabidopsis Hexokinase1 in Cell Death Mediated by Myo-Inositol Accumulation.

Citation data:

The Plant cell, ISSN: 1532-298X, Vol: 27, Issue: 6, Page: 1801-14

Publication Year:
2015
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Abstract Views 46
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Captures 48
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Citations 11
Citation Indexes 11
Repository URL:
http://hdl.handle.net/10754/575652
PMID:
26048869
DOI:
10.1105/tpc.15.00068
PMCID:
PMC4498202
Author(s):
Bruggeman, Quentin; Prunier, Florence; Mazubert, Christelle; de Bont, Linda; Garmier, Marie; Lugan, Raphaël; Benhamed, Moussa; Bergounioux, Catherine; Raynaud, Cécile; Delarue, Marianne
Publisher(s):
American Society of Plant Biologists (ASPB)
Tags:
Agricultural and Biological Sciences; Biochemistry, Genetics and Molecular Biology
article description
Programmed cell death (PCD) is essential for several aspects of plant life, including development and stress responses. We recently identified the mips1 mutant of Arabidopsis thaliana, which is deficient for the enzyme catalyzing the limiting step of myo-inositol (MI) synthesis. One of the most striking features of mips1 is the light-dependent formation of lesions on leaves due to salicylic acid (SA)-dependent PCD. Here, we identified a suppressor of PCD by screening for mutations that abolish the mips1 cell death phenotype. Our screen identified the hxk1 mutant, mutated in the gene encoding the hexokinase1 (HXK1) enzyme that catalyzes sugar phosphorylation and acts as a genuine glucose sensor. We show that HXK1 is required for lesion formation in mips1 due to alterations in MI content, via SA-dependant signaling. Using two catalytically inactive HXK1 mutants, we also show that hexokinase catalytic activity is necessary for the establishment of lesions in mips1. Gas chromatography-mass spectrometry analyses revealed a restoration of the MI content in mips1 hxk1 that it is due to the activity of the MIPS2 isoform, while MIPS3 is not involved. Our work defines a pathway of HXK1-mediated cell death in plants and demonstrates that two MIPS enzymes act cooperatively under a particular metabolic status, highlighting a novel checkpoint of MI homeostasis in plants.