WRKY1 Mediates Transcriptional Regulation of Light and Nitrogen Signaling Pathways

Abstract

Plant responses to multiple environmental stimuli must be integrated to enable them to adapt their metabolism and development. Light and nitrogen (N) are two such stimuli whose downstream signaling pathways must be intimately connected to each other to control plant energy status. Here, we describe the functional role of the WRKY1 transcription factor in controlling genome-wide transcriptional reprogramming of Arabidopsis (Arabidopsis thaliana) leaves in response to individual and combined light and N signals. This includes a cross-regulatory network consisting of 724 genes regulated by WRKY1 and involved in both N and light signaling pathways. The loss of WRKY1 gene function has marked effects on the light and N response of genes involved in N uptake and assimilation (primary metabolism) as well as stress response pathways (secondary metabolism). Our results at the transcriptome and at the metabolite analysis level support a model in which WRKY1 enables plants to activate genes involved in the recycling of cellular carbon resources when light is limiting but N is abundant and upregulate amino acid metabolism when both light and N are limiting. In this potential energy conservation mechanism, WRKY1 integrates information about cellular N and light energy resources to trigger changes in plant metabolism. QJ (2005) Annotations and functional analyses of the rice WRKY gene superfamily reveal positive and negative regulators of abscisic acid signaling in aleurone cells. Plant Physiol 137: 176-189 Zhou X, Jiang Y, Yu D (2011) WRKY22 transcription factor mediates darkinduced leaf senescence in Arabidopsis.

Morphological Physiological and Transcriptional Response to Low Nitrogen Stress in Populus Deltoides Marsh. Clones With Contrasting Nitrogen Use Efficiency

“…Among the TFs found in this study, WRKY TFs, regulating a variety of hormone signaling pathways [58]; bHLH TFs, one of the largest TF families in plants, regulating plant growth and signal transduction [59]; and bZIP TFs, regulating processes including pathway defense, light, and stress signaling [60], were detected in response to low N stress. These TFs were identified as being responsive to N availability in maize [8], Arabidopsis [56], and rice [57]. Moreover, the PodelWRKY18 (Podel.18G019200) was specifically upregulated in N-efficient and N-inefficient genotypes under low N stress, which was consistent with previously published results [56].…”

An Integrated Analysis of the Rice Transcriptome and Metabolome Reveals Root Growth Regulation Mechanisms in Response to Nitrogen Availability

“…In the current study, TF families such as bHLH, NAC, MYB-related, WRKY, and ERF were identified as being responsive to nitrogen availability, of which the WRKY family’s members were specifically upregulated under low-nitrogen conditions (Table 1). Heerah et al [36] found that WRKY1 activates the transcription of GDH1 , NIA1 , NIA2 , NRT2.1 , and AMT1.1 in Arabidopsis . Imamura et al [37] also found that in Cyanidioschyzon merolae MYB1 can enhance nitrogen assimilation in nitrogen deficiency by regulating NRT, NAR, NIR, and GS expression.…”

Morphological, physiological, and transcriptional responses to low nitrogen stress in Populus deltoides Marsh. clones with contrasting nitrogen use efficiency

“…Among the TFs found in this study, WRKY TFs, regulating a variety of hormone signaling pathways [ 59 ]; bHLH TFs, one of the largest TF families in plants, regulating plant growth and signal transduction [ 60 ]; and bZIP TFs, regulating processes including pathway defense, light, and stress signaling [ 61 ], were detected in response to low N stress. These TFs were identified as being responsive to N availability in maize [ 8 ], Arabidopsis [ 57 ], and rice [ 58 ]. Moreover, the PodelWRKY18 (Podel.18G019200) was specifically upregulated in N-efficient and N-inefficient genotypes under low N stress, which was consistent with previously published results [ 57 ].…”

“…These TFs were identified as being responsive to N availability in maize [ 8 ], Arabidopsis [ 57 ], and rice [ 58 ]. Moreover, the PodelWRKY18 (Podel.18G019200) was specifically upregulated in N-efficient and N-inefficient genotypes under low N stress, which was consistent with previously published results [ 57 ].…”