Arabidopsis GCN2 kinase contributes to ABA homeostasis and stomatal immunity

Liu, Xiaoyu; Afrin, Taiaba; Pajerowska-Mukhtar, Karolina M.

doi:10.1038/s42003-019-0544-x

Cited by 49 publications

(43 citation statements)

References 77 publications

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“…This conclusion is also in keeping with the emerging role of GCN2 in responses to plant pathogens. Under certain conditions, pathogens or effectors of immunity activate GCN2 or eIF2α phosphorylation (Pajerowska-Mukhtar et al, 2012;Liu et al, 2019) while in other conditions they do not (Zhang et al, 2008;Meteignier et al, 2017;Izquierdo et al, 2018). Certain pathogens do trigger translational reorganizations (Moeller et al, 2012;Xu et al, 2017) and GCN2 is involved in responses to bacterial pathogens (Liu et al, 2015b;Liu et al, 2019;Lokdarshi et al, 2019) although the precise role of GCN2 kinase signaling in defense related translational control remains to be defined.…”

Section: Discussionmentioning

confidence: 99%

Light dependent activation of the GCN2 kinase under cold and salt stress is mediated by the photosynthetic status of the chloroplast

Lokdarshi

Morgan

Franks

et al. 2019

Preprint

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ABSTRACTRegulation of cytosolic mRNA translation is a key node for rapid adaptation to environmental stress conditions. In yeast and animals, phosphorylation of the α-subunit of eukaryotic translation initiation factor eIF2 is the most thoroughly characterized event in regulating global translation under stress. In plants, the GCN2 kinase (General Control Non-derepressible-2) is the only known kinase for eIF2α. GCN2 is activated under a variety of stresses including reactive oxygen species. Here we provide new evidence that the GCN2 kinase in Arabidopsis is also activated rapidly and in a light dependent manner by cold and salt treatments. These treatments alone did not repress global mRNA ribosome loading in a major way. The activation of GCN2 was attenuated by inhibitors of photosynthesis and antioxidants, suggesting that it is gated by the redox poise or the reactive oxygen status of the chloroplast. In keeping with these results, gcn2 mutant seedlings were more sensitive than wild type to both cold and salt in a root elongation assay. These data suggest that cold and salt stress may both affect the status of the cytosolic translation apparatus via the conserved GCN2-eIF2α module. The potential role of the GCN2 kinase pathway in the global repression of translation under abiotic stress will be discussed.

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Section: Discussionmentioning

confidence: 99%

Light dependent activation of the GCN2 kinase under cold and salt stress is mediated by the photosynthetic status of the chloroplast

Lokdarshi

Morgan

Franks

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…Upon infection with Pseudomonas syringae, the GCN2-eIF2α module is involved in the regulation of genes encoding ABA receptors, ABA biosynthetic enzymes, and ABA-related transcription factors (X. Liu et al, 2019). These studies indicate specific adjustments to gene expression via the GCN2-eIF2α module.…”

Section: The Gcn2 Kinasementioning

confidence: 99%

“…Attempts to identify GCN2-resistant targets of translational control led to the Arabidopsis transcription factor TBF1/HsfB1, which functions in response to pathogens (X. Liu, Afrin, & Pajerowska-Mukhtar, 2019;Pajerowska-Mukhtar et al, 2012); coincidentally, its CPuORF confers translational repression in response to galactinol, a precursor of the trisaccharide raffinose (X. Zhu, Li, Fang, & Kusano, 2018).…”

Section: The Gcn2 Kinasementioning

confidence: 99%

Translational gene regulation in plants: A green new deal

2020

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The molecular machinery for protein synthesis is profoundly similar between plants and other eukaryotes. Mechanisms of translational gene regulation are embedded into the broader network of RNA-level processes including RNA quality control and RNA turnover. However, over eons of their separate history, plants acquired new components, dropped others, and generally evolved an alternate way of making the parts list of protein synthesis work. Research over the past 5 years has unveiled how plants utilize translational control to defend themselves against viruses, regulate translation in response to metabolites, and reversibly adjust translation to a wide variety of environmental parameters. Moreover, during seed and pollen development plants make use of RNA granules and other translational controls to underpin developmental transitions between quiescent and metabolically active stages. The economics of resource allocation over the daily light-dark cycle also include controls over cellular protein synthesis. Important new insights into translational control on cytosolic ribosomes continue to emerge from studies of translational control mechanisms in viruses. Finally, sketches of coherent signaling pathways that connect external stimuli with a translational response are emerging, anchored in part around TOR and GCN2 kinase signaling networks. These again reveal some mechanisms that are familiar and others that are different from other eukaryotes, motivating deeper studies on translational control in plants.

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“…Aside from inhibitors of amino acid biosynthesis, plant GCN2 kinase is activated by numerous other agents, including ultraviolet light, wounding, the ethylene precursor 1-aminocyclopropane carboxylic acid, the endogenous defense signals salicylic acid and methyl-jasmonate and bacterial infection (Lageix et al, 2008;Liu et al, 2019). What remains unclear is the nature of the biochemical signal that activates GCN2 under this variety of abiotic and biotic stresses.…”

Section: Introductionmentioning

confidence: 99%

Light-Dependent Activation of the GCN2 Kinase Under Cold and Salt Stress Is Mediated by the Photosynthetic Status of the Chloroplast

et al. 2020

View full text Add to dashboard Cite

Regulation of cytosolic mRNA translation is a key node for rapid adaptation to environmental stress conditions. In yeast and animals, phosphorylation of the α-subunit of eukaryotic translation initiation factor eIF2 is the most thoroughly characterized event for regulating global translation under stress. In plants, the GCN2 kinase (General Control Nonderepressible-2) is the only known kinase for eIF2α. GCN2 is activated under a variety of stresses including reactive oxygen species (ROS). Here, we provide new evidence that the GCN2 kinase in Arabidopsis is also activated rapidly and in a light-dependent manner by cold and salt treatments. These treatments alone did not repress global mRNA ribosome loading in a major way. The activation of GCN2 was accompanied by a more oxidative environment and was attenuated by inhibitors of photosynthetic electron transport, suggesting that it is gated by the redox poise or the reactive oxygen status of the chloroplast. In keeping with these results, gcn2 mutant seedlings were more sensitive than wild type to both cold and salt in a root elongation assay. These data suggest that cold and salt stress may both affect the status of the cytosolic translation apparatus via the conserved GCN2-eIF2α module. The potential role of the GCN2 kinase pathway in the global repression of translation under abiotic stress is discussed.

show abstract

Arabidopsis GCN2 kinase contributes to ABA homeostasis and stomatal immunity

Cited by 49 publications

References 77 publications

Light dependent activation of the GCN2 kinase under cold and salt stress is mediated by the photosynthetic status of the chloroplast

Light dependent activation of the GCN2 kinase under cold and salt stress is mediated by the photosynthetic status of the chloroplast

Translational gene regulation in plants: A green new deal

Light-Dependent Activation of the GCN2 Kinase Under Cold and Salt Stress Is Mediated by the Photosynthetic Status of the Chloroplast

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