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要旨

ABSTRACTPlants are constantly exposed to environmental changes that affect their performance. Metabolic adjustments are crucial to control energy homeostasis and plant survival, particularly during stress. Under carbon starvation conditions, coordinated reprogramming is initiated to adjust metabolic processes, which culminate in premature senescence. This fact notwithstanding, the regulatory networks that modulate transcriptional control during low energy remain poorly understood. Here, we show that the WRKY45 transcription factor (TF) is highly induced during both developmental and dark-induced senescence. The overexpression of Arabidopsis WRKY45 resulted in an early senescence phenotype characterized by a reduction of maximum photochemical efficiency of photosystem II and chlorophyll levels in the later stages of darkness. The detailed metabolic characterization showed significant changes in amino acids coupled with the accumulation of organic acids in WRKY45 overexpression lines during dark-induced senescence. Furthermore, the markedly up-regulation of alternative oxidase (AOX1a, AOX1d) and electron transfer flavoprotein/ubiquinone oxidoreductase (ETFQO) genes suggested that WRKY45 is likely associated with a dysregulation of mitochondrial signalling and the activation of alternative respiration rather than amino acids catabolism regulation. Collectively our results provided molecular evidence that WRKY45 is involved in the plant metabolic reprogramming following carbon starvation and highlight the potential role of WRKY45 in the modulation of mitochondrial signalling pathways.This article is protected by copyright. All rights reserved.