Functional characterization of inositol pyrophosphates in arabidopsis thaliana

Autori

• Debabrata Laha

Parametri

• Libri di testo
• Libri di testo universitari

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Diphosphorylated inositol polyphosphates, or inositol pyrophosphates, are energy-rich molecules that regulate essential molecular events across eukaryotic organisms. In mammals and fungi, their biosynthesis is mediated by two classes of inositol polyphosphate kinases: Kcs1/IP6K- and Vip1/PPIP5K-like proteins. While more polar inositol polyphosphate molecules than InsP6 have been found in some plants, their synthesis, isomer identity, and physiological functions remain largely unexplored. This study reveals that PPIP5K homologs are prevalent in plants and identifies Arabidopsis VIH1 and VIH2 as functional PPIP5K enzymes. It demonstrates that jasmonate specifically induces the inositol pyrophosphate InsP8, with both steady-state and jasmonate-induced InsP8 levels relying on VIH2. Investigations involving vih2 loss-of-function lines, in silico docking, and in vitro radioligand binding assays indicate that InsP8 serves as a crucial co-factor for the ASK1-COI1-JAZ jasmonate coreceptor complex, significantly influencing plant defense against insect herbivores and necrotrophic fungi. Additionally, the F-box component COI1 is shown to determine the inositol polyphosphate binding specificity of the jasmonate receptor, suggesting that the simultaneous detection of jasmonate and inositol pyrophosphate is vital for hormone perception.

Lingua: Inglese

Pubblicato: 2017