Multiparametric real‐time sensing of cytosolic physiology links hypoxia responses to mitochondrial electron transport

Abstract

Hypoxia regularly occurs during plant development and can be induced by the environment through, for example, flooding.To understand how plant tissue physiology responds to progressing oxygen restriction, we aimed to monitor subcellular physiology in real time and in vivo. We establish a fluorescent protein sensor-based system for multiparametric monitoring of dynamic changes in subcellular physiology of living Arabidopsis thaliana leaves and exemplify its applicability for hypoxia stress.By monitoring cytosolic dynamics of magnesium adenosine 5'-triphosphate, free calcium ion concentration, pH, NAD redox status, and glutathione redox status in parallel, linked to transcriptional and metabolic responses, we generate an integrated picture of the physiological response to progressing hypoxia. We show that the physiological changes are surprisingly robust, even when plant carbon status is modified, as achieved by sucrose feeding or extended night. Inhibition of the mitochondrial respiratory chain causes dynamics of cytosolic physiology that are remarkably similar to those under oxygen depletion, highlighting mitochondrial electron transport as a key determinant of the cellular consequences of hypoxia beyond the organelle. A broadly applicable system for parallel in vivo sensing of plant stress physiology is established to map out the physiological context under which both mitochondrial retrograde signalling and low oxygen signalling occur, indicating shared upstream stimuli.

The Arabidopsis mitochondrial dicarboxylate carrier 2 maintains leaf metabolic homeostasis by uniting malate import and citrate export

“…via a malate shuttle) (4), we hypothesised that a PIB increase in dic2-1 could be linked to altered distribution of TCA cycle metabolites between mitochondria and cytosol (and possibly plastids), leading to changes in metabolic and/or NAD redox state in these compartments. To capture any rapid and transient changes in NAD redox state during a sudden dark shift, we utilised a fluorescent protein biosensor Peredox‐mCherry which reports cytosolic NADH/NAD + through the ratio of tSapphire to mCherry fluorescence (log 10 (tS/mC)), where a higher log 10 (tS/mC) corresponds to a more reduced NAD pool (38, 39). We observed equally high NADH/NAD + ratios in Col-0 and dic2-1 plants during illumination (Fig.…”

Comparative Transcriptome Analysis Reveals the Potential Mechanism of Abortion in Tobacco sua-Cytoplasmic Male Sterility

“…Decreased ATP production was considered the reason for pollen abortion in transgenic tobacco [27] and rice [60]. Mitochondrial energy metabolism is mitochondria utilizing oxygen to produce ATP via OXPHOS, so mitochondrial energy metabolism is importantly linked to hypoxia [61]. While redox status is an important determinant of germ cell development in pre-sporogenous stage [62]-for example, hypoxic around the tassel, triggering archesporial cells formation and manipulating redox status-any lobe cell can become an archesporial cell in maize.…”

Dual-sensing genetically encoded fluorescent indicators resolve the spatiotemporal coordination of cytosolic abscisic acid and second messenger dynamics in Arabidopsis

“…Multiplexed live imaging in plants has been performed via the combination of GEFIs with fluorescent dyes, the use of GEFIs in parallel experiments, or through dual-expression of Ca 2+ indicators (Monshausen et al, 2007, 2009, 2011; Loro et al, 2012; Schwarzländer et al, 2012; Ngo et al, 2014; Keinath et al, 2015; Behera et al, 2018; Kelner et al, 2018; Wagner et al, 2019). However, GEFI-based simultaneous analyses of two signaling compounds has been established in Arabidopsis only for Ca 2+ and ABA (Waadt et al, 2017).…”