Four distinct types of dehydration stress memory genes in Arabidopsis thaliana
Arabidopsis plants that have experienced stress from water withdrawal show an improved ability to tolerate subsequent exposures as a ‘memory’ from the previous stress. This physiological stress memory is associated with ‘transcriptional memory’ illustrated by a subset of dehydrations stress responding genes that produce significantly different transcript amounts during repeated dehydration stresses relative to their response in the first. Here we report the genome-wide representation of dehydration stress transcriptional memory genes in A. thaliana. We identify four novel transcription patterns in response to repeated dehydration stress treatments. The nature of the proteins encoded by genes from each type of memory-response pattern is analyzed and the consequences of the genes’ memory behavior are considered in the context of possible biological relevance. The memory behavior of genes co-regulated by the dehydration/ABA and other abiotic stress and hormone responding pathways suggested that the crosstalk at the transcriptional level between them was affected as well. The intensity and the nature of specific biochemical, membrane, chloroplast, and stress response-related interactions during multiple exposures to dehydration stress are different from the responses to a single dehydration stress. The results reveal additional, hitherto unknown, levels of complexity of the plants’ transcriptional behavior when adjusting and adapting to recurring water deficits. Overall design: For each condition (water, S1, and S3) the transcriptome was sequenced for two replicates. The watered condition is considered the control.