Regulatory Functions of SnRK1 in Stress-Responsive Gene Expression and in Plant Growth and Development      

Abstract

Sucrose-nonfermentation1-related protein kinase1 (SnRK1) is an evolutionarily conserved energy sensor protein that regulates gene expression in response to energy depletion in plants. Efforts to elucidate the functions and mechanisms of this protein kinase are hampered, however, by inherent growth defects of snrk1-null mutant plants. To overcome these limitations and study SnRK1 functions in vivo, we applied a method combining transient expression in leaf mesophyll protoplasts and stable expression in transgenic plants. We found that both rice (Oryza sativa) and Arabidopsis (Arabidopsis thaliana) SnRK1 activities critically influence stress-inducible gene expression and the induction of stress tolerance. Genetic, molecular, and chromatin immunoprecipitation analyses further revealed that the nuclear SnRK1 modulated target gene transcription in a submergencedependent manner. From early seedling development through late senescence, SnRK1 activities appeared to modulate developmental processes in the plants. Our findings offer insight into the regulatory functions of plant SnRK1 in stressresponsive gene regulation and in plant growth and development throughout the life cycle.

Acclimation of metabolism to light in Arabidopsis thaliana: the glucose 6‐phosphate/phosphate translocator GPT2 directs metabolic acclimation

“…G6P inhibition of SnRK1 could therefore have a significant effect on metabolism as it provides a convergence point for regulatory networks (Cho et al . 2010). By altering the relative concentrations of G6P (and hence other metabolites), GPT2 may thus affect a number of metabolic signals controlling gene expression and/or protein synthesis.…”

The role of sugar signaling in plant defense responses against fungal pathogens

“…At a threat of cell energy deficit SnRK1 regulates the expression of over 1,000 genes, restoring cell homeostasis by repressing energy-intensive anabolic pathways and activating catabolism genes (Baena-Gonzalez 2010). Studies conducted on transgenic plants with the expression of the inactive SnRK1 form showed that this kinase is responsible for the activation of genes by stress conditions, as e.g., the expression of two marker genes for the flooding stress response, alcohol dehydrogenase 1 and pyruvate decarboxylase 1 was found only in plants expressing wild-type SnRK1 (Cho et al 2012). However, this activation may be abolished in wild plants by the addition of exogenous 90 mM sucrose.…”

“…There are many reports on the importance of sugar levels in plant resistance to diseases caused by fungal pathogens and oomycetes, but their role as signal molecules in defense responses has only been described in recent publications (Doehlemann et al 2008;Morkunas et al 2011;Bolouri Moghaddam and Van den Eden 2012). This influx of novel data has been provided by studies on mutants, primarily Arabidopsis thaliana, with disturbed sugar signaling pathways, on transgenic plants and thanks to the results supplied by analyses of gene expression (Cho et al 2012;Schenk et al 2012). Research on molecular plant responses to abiotic stresses also provides information which is useful in the interpretation of reactions occurring in plants during fungal pathogen attack (Hey et al 2010).…”

Waterproofing Crops: Effective Flooding Survival Strategies

“…In Arabidopsis, the energy-sensing SnRK1s are KIN10 and KIN11, which manage carbon utilization under hypoxia and/or carbohydrate starvation (Baena-González et al, 2007). KIN10 positively regulates the S group of bZIP transcription factors, genes associated with carbohydrate and amino acid catabolism, nighttime starch breakdown, and leaf senescence (Baena-González et al, 2007;Cho et al, 2012). Included among the KIN10/11-regulated genes is EXORDIUM-LIKE1, a HUP that is necessary for carbon management under oxygen deprivation (Schröder et al, 2011).…”