Transcriptome profiling illustrates expression signatures of dehydration tolerance in developing grasspea seedlings

摘要

Main conclusionThis study highlights dehydration-mediated temporal changes in physicochemical, transcriptome and metabolome profiles indicating altered gene expression and metabolic shifts, underlying endurance and adaptation to stress tolerance in themarginalized crop, grasspea.Grasspea, often regarded as an orphan legume, is recognized to befairly tolerant to water-deficit stress. In the present study, 3-week-old grasspea seedlings were subjected to dehydration by withholding water over a period of 144h. While there were no detectable phenotypic changes in the seedlings till 48h, the symptoms appeared during 72h and aggravated upon prolonged dehydration. The physiological responses to water-deficit stressduring 72-96h displayed a decrease in pigments, disruption in membrane integrity and osmotic imbalance. We evaluated the temporal effects of dehydration at the transcriptome and metabolome levels. In total, 5201 genes of various functional classes including transcription factors, cytoplasmic enzymes and structural cell wall proteins, among others, were found to be dehydration-responsive. Further, metabolome profiling revealed 59 dehydration-responsive metabolites including sugar alcohols and amino acids. Despite the lack of genome information of grasspea, the time course of physicochemical and molecular responses suggest a synchronized dehydration response. The cross-species comparison of the transcriptomes and metabolomes with other legumes provides evidence for marked molecular diversity. We propose a hypothetical model that highlights novel biomarkers and explain their relevance in dehydration-response, which would facilitate targeted breeding and aid in commencing crop improvement efforts.