Temporal analysis of physiological, metabolite and transcriptome responses during drought identifies distinct early and late phases in Arabidopsis

ABSTRACT: Water availability is the biggest single limitation on plant productivity worldwide. In Arabidopsis, adjustments to drought stress, involving changes in metabolism and gene expression drive increased drought tolerance and initiate diverse drought avoidance and escape responses. To address regulatory processes that integrate these complex responses we hypothesised that we needed to identify genes that govern early responses to drought. To this end, we produced a high-resolution time series transcriptomics dataset, coupled with detailed physiological and metabolic analyses of plants subjected to a slow transition from well-watered to the onset of drought conditions. 1825 differentially expressed genes (DEGs) were identified which showed no significant enrichment in gene ontology terms associated with dehydration responses and abscisic acid (ABA) regulation, confirming that the gene expression time series had targeted events prior to severe drought stress. Initial changes in gene expression coincided with a drop in carbon assimilation, not the later increase in foliar ABA content. Thus the early physiological and gene expression responses to drought were not driven by changes in leaf ABA content. In order to identify gene regulatory networks (GRNs) linked to early events, we used Bayesian network modelling of differentially expressed transcription factor (TF) genes. This approach identified AGAMOUS-LIKE 22 as key hub gene in a TF GRN. AGL22 is involved in the transition from vegetative state to flowering. Loss of AGL22 expression affected flowering time and drying rate providing a link between early changes in metabolism and the subsequent initiation of developmental responses to stress that govern plant productivity.

ORGANISM(S): Arabidopsis thaliana

PROVIDER: GSE65046 | GEO | 2016/02/29

SECONDARY ACCESSION(S): PRJNA272977

REPOSITORIES: GEO