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Plant Stress Signaling

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http://hdl.handle.net/10400.7/105

We are ultimately interested in signaling processes that operate ubiquitously in Nature, such as those related to the nutrient and energy status, and in how they have been modified to the needs of autotrophic and multi-cellular plants. In contrast to animals, plant growth is largely conditioned by environmental inputs. Such plasticity allows the plant to optimise its growth and development according to the prevailing conditions, ensuring the best possible chance to complete its life cycle and contributing to the striking phenotypic variation of the plant kingdom. Stress can have a great impact on growth, on developmental transitions, as well as on the characteristics of newly formed organs. Often associated with stress is a reduction in photosynthesis and/or respiration, which in turn results in an energy deficit in the cell. Dealing with such imbalances in the energy status is of uttermost importance, since even short periods of starvation can cause growth arrest and result, for example, in seed abortion characteristic of episodes of drought and heat.

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Massachusetts General Hospital, Harvard Medical School, Boston, USA Jen Sheen

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Browsing Plant Stress Signaling by Author "Bachmair, Andreas"

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  • SUMOylation represses SnRK1 signaling in Arabidopsis
    Publication . Crozet, Pierre; Margalha, Leonor; Butowt, Rafal; Fernandes, Noémia; Elias, Carlos A.; Orosa, Beatriz; Tomanov, Konstantin; Teige, Markus; Bachmair, Andreas; Sadanandom, Ari; Baena-González, Elena
    The SnRK1 protein kinase balances cellular energy levels in accordance with extracellular conditions and is thereby key for plant stress tolerance. In addition, SnRK1 has been implicated in numerous growth and developmental processes from seed filling and maturation to flowering and senescence. Despite its importance, the mechanisms that regulate SnRK1 activity are poorly understood. Here, we demonstrate that the SnRK1 complex is SUMOylated on multiple subunits and identify SIZ1 as the E3 Small Ubiquitin-like Modifier (SUMO) ligase responsible for this modification. We further show that SnRK1 is ubiquitinated in a SIZ1-dependent manner, causing its degradation through the proteasome. In consequence, SnRK1 degradation is deficient in siz1-2 mutants, leading to its accumulation and hyperactivation of SnRK1 signaling. Finally, SnRK1 degradation is strictly dependent on its activity, as inactive SnRK1 variants are aberrantly stable but recover normal degradation when expressed as SUMO mimetics. Altogether, our data suggest that active SnRK1 triggers its own SUMOylation and degradation, establishing a negative feedback loop that attenuates SnRK1 signaling and prevents detrimental hyperactivation of stress responses.
    2015-12-30Journal article Open access Show more