The low energy signaling network

Abstract

Stress impacts negatively on plant growth and crop productivity, caicultural production worldwide. Throughout their life, plants are often confronted with multiple types of stress that affect overall cellular energy status and activate energy-saving responses. The resulting low energy syndrome (LES) includes transcriptional, translational, and metabolic reprogramming and is essential for stress adaptation. The conserved kinases sucrose-non-fermenting-1-related protein kinase-1 (SnRK1) and target of rapamycin (TOR) play central roles in the regulation of LES in response to stress conditions, affecting cellular processes and leading to growth arrest and metabolic reprogramming. We review the current understanding of how TOR and SnRK1 are involved in regulating the response of plants to low energy conditions. The central role in the regulation of cellular processes, the reprogramming of metabolism, and the phenotypic consequences of these two kinases will be discussed in light of current knowledge and potential future developments.

Herbicide-related signaling in plants reveals novel insights for herbicide use strategies, environmental risk assessment and global change assessment challenges

“…However, xenobiotic stress is generally related to significant perturbations of carbon and nitrogen metabolic integration, with major variations of soluble sugars (Serra et al, , 2015a(Serra et al, , 2015b, and is strongly affected by the carbon status (Ramel et al, 2007(Ramel et al, , 2009a(Ramel et al, , 2009b. The distinct nutritional conditions of high or low carbon:nitrogen ratios used respectively by Zhang et al (2008) and Faus et al (2015) reflect contrasting situations of carbohydrate availability or limitation (Tomé et al, 2014). The differential impact of the gcn2 mutation on glyphosate responses may thus result from interactions between GCN2, or other components of the regulatory pathway, and the carbon and nitrogen status of the plant for the management of amino acid fluxes.…”

“…Some of these effectors interact with master regulators of metabolism, such as the SNF1 (sucrose non-fermenting 1)-related kinase 1 (SnRK1) (Baena-González et al, 2007;Emanuelle et al, 2015;Tomé et al, 2014) and the target-ofrapamycin (TOR) kinase (Tomé et al, 2014;Xiong et al, 2013), which exert major controls on the regulation of genes involved in catabolic processes (proteolysis, amino acid catabolism, sugar degradation, lipid catabolism) that can compensate low carbohydrate and low energy situations. In Arabidopsis, SnRK1 acts through the activation of bZIP transcription factors on asparagine biosynthesis and branched-chain amino acid metabolism (Dietrich et al, 2011), and the dynamics of these important amino acids is affected by chemically-and functionally-diverse herbicides, such as acetolactate synthase inhibitors (Duhoux et al, 2015), glyphosate (Serra et al, , 2015a(Serra et al, , 2015bVivancos et al, 2011), or atrazine , by the atrazine derivative hydroxyatrazine (Serra et al, , 2015a, and by the glyphosate derivative aminomethylphosphonic acid (AMPA) (Serra et al, , 2015a.…”

“…Herbicide treatments modify metabolic networks that include generegulating metabolic signals (Ramel et al, 2007(Ramel et al, , 2009aSerra et al, , 2015aSerra et al, , 2015bVivancos et al, 2011), such as sucrose, glucose, trehalose, serine, or leucine, which are major effectors of the sensing mechanisms that integrate metabolism, stress and development (Emanuelle et al, 2015;Tomé et al, 2014). Some of these effectors interact with master regulators of metabolism, such as the SNF1 (sucrose non-fermenting 1)-related kinase 1 (SnRK1) (Baena-González et al, 2007;Emanuelle et al, 2015;Tomé et al, 2014) and the target-ofrapamycin (TOR) kinase (Tomé et al, 2014;Xiong et al, 2013), which exert major controls on the regulation of genes involved in catabolic processes (proteolysis, amino acid catabolism, sugar degradation, lipid catabolism) that can compensate low carbohydrate and low energy situations.…”

Dynamic and diverse sugar signaling

“…Under sugar deprivation conditions, the evolutionarily conserved energy sensor complex SNRK1 plays central regulatory functions in metabolism, stress signaling and plant development [9,10,15,21,23,24]. In Arabidopsis , KIN10/11 protein kinases provide catalytic activities in the SNRK1 complex and orchestrate global gene expression changes to activate catabolism but repress anabolism [21,23, 24,70].…”

Quantitative phosphoproteomics reveals the role of the AMPK plant ortholog SnRK1 as a metabolic master regulator under energy deprivation

“…However, it is still unclear if this connection exists in plants, but there is evidence that TOR and SnRK1 pathways have antagonistic roles depending on the energy availability (for review, see refs 23,36,37). …”