HEXOKINASE-dependent regulation of WRKY transcription factors in Arabidopsis

Abstract

Sugars are the major product of photosynthesis and provide the stored energy and basic building blocks for all living cells. Sugars also act as dynamic signals throughout the plant life cycle to regulate growth, development and interactions with the biotic and abiotic environment. From a previous RNA-seq experiment, we have identified eight sugar-regulated WRKY transcription factor genes. Focusing on four, we find that WRKY11, WRKY17, WRKY60 and WRKY72 are upregulated by sucrose, glucose or fructose by a superoxide signalling pathway. WRKY gene expression is downregulated by 2-deoxyglucose (2-DG) or mannose, which are inhibitors of hexokinase (HXK), and in hxk1-3 mutants. Mutants in WRKY17, WRKY60 or WRKY72 have reduced hypocotyl growth in response to sucrose, but do not have altered circadian period. Our data suggest that HXK1-dependent regulation of WRKY genes by sugars represents a superoxide-activated transcriptional subnetwork that influences plant growth. HighlightWRKY11, WRKY17, WRKY60 and WRKY72 are upregulated by a sugar-activated superoxide signalling pathway in a HKX1-dependent manner. These sugar-regulated WRKYs represent a transcriptional subnetwork promoting plant growth.