Expression of Arabidopsis FCS-Like Zinc finger genes is differentially regulated by sugars, cellular energy level, and abiotic stress

Abstract

Cellular energy status is an important regulator of plant growth, development, and stress mitigation. Environmental stresses ultimately lead to energy deficit in the cell which activates the SNF1-RELATED KINASE 1 (SnRK1) signaling cascade which eventually triggering a massive reprogramming of transcription to enable the plant to survive under low-energy conditions. The role of Arabidopsis thaliana FCS-Like Zinc finger (FLZ) gene family in energy and stress signaling is recently come to highlight after their interaction with kinase subunits of SnRK1 were identified. In a detailed expression analysis in different sugars, energy starvation, and replenishment series, we identified that the expression of most of the FLZ genes is differentially modulated by cellular energy level. It was found that FLZ gene family contains genes which are both positively and negatively regulated by energy deficit as well as energy-rich conditions. Genetic and pharmacological studies identified the role of HEXOKINASE 1- dependent and energy signaling pathways in the sugar-induced expression of FLZ genes. Further, these genes were also found to be highly responsive to different stresses as well as abscisic acid. In over-expression of kinase subunit of SnRK1, FLZ genes were found to be differentially regulated in accordance with their response toward energy fluctuation suggesting that these genes may work downstream to the established SnRK1 signaling under low-energy stress. Taken together, the present study provides a conceptual framework for further studies related to SnRK1-FLZ interaction in relation to sugar and energy signaling and stress response.

FCS‐like zinc finger 6 and 10 repress SnRK1 signalling in Arabidopsis

“…SnRK1 is a central regulator of growth during energy deficit. Previously we demonstrated that energy status and SnRK1 regulate the expression of FLZ genes (Jamsheer K and Laxmi, ). Here we show that two FLZ proteins, FLZ6 and FLZ10, negatively regulate the level of SnRK1α1.…”

“…FLZ10 was also found to be induced in response to mild starvation; however, prolonged starvation repressed its transcription. Further, FLZ6 is induced in response to treatment with 2‐deoxy‐ d ‐glucose (2DG) which causes energy depletion by blocking glycolysis (Jamsheer K and Laxmi, ). To analyse whether FLZ10 is also regulated by the reduction in cellular energy, its expression was checked in seedlings treated with increasing concentrations of 2DG.…”

“…During energy starvation, SnRK1, through downstream transcription factors such as bZIPs, alters the expression of a large number of genes (Baena‐González et al ., ; Mair et al ., ). The expression of FLZ6 and FLZ10 is induced during energy starvation (Figure a; Jamsheer K and Laxmi, ). To understand whether SnRK1 signalling has any role in controlling the expression of these genes during energy starvation, we analysed their transcript level in a previously reported overexpression line SnRK1 α 1 OE2 before and after energy starvation (Baena‐González et al ., ).…”

“…Interestingly, reduced expression of these genes in their respective mutants resulted in the accumulation of SnRK1α1, suggesting that neither of these genes can completely replace the other in function. This could be attributed to the divergence in their expression pattern (Jamsheer K and Laxmi, ; Nietzsche et al ., ). In summary, this work highlights the presence of a plant‐specific regulatory component of the eukaryotic energy gauge, SnRK1.…”

Molecular signatures of local adaptation to light in Norway Spruce: role of lignin mediated immunity

“…SnRK1 signalling cascade involves interaction of FLZ gene family members with the kinase subunits. Expression of FLZ genes is both positively and negatively regulated by energy deficit as well as energy-rich conditions (Jamsheer and Laxmi, 2015). Starvation or low energy induces expression of FLZ6, SnRK1 also induces FLZ6 during energy starvation.…”