Transcriptomics and physiological analyses reveal co-ordinated alteration of metabolic pathways in Jatropha curcas drought tolerance

• Published in: Journal of experimental botany Vol. 67; no. 3; pp. 845 - 860
• Main Authors: Sapeta, Helena, Lourenço, Tiago, Lorenz, Stefan, Grumaz, Christian, Kirstahler, Philipp, Barros, Pedro M., Costa, Joaquim Miguel, Sohn, Kai, Oliveira, M. Margarida
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01-02-2016
• Subjects: Adaptation, Physiological - genetics; Chlorophyll - metabolism; Chromatography, High Pressure Liquid; Cluster Analysis; Desiccation; Droughts; Galactose - metabolism; Gases - metabolism; Gene Expression Profiling - methods; Gene Expression Regulation, Plant; Genes, Plant; Jatropha - genetics; Jatropha - growth & development; Jatropha - physiology; Metabolic Networks and Pathways - genetics; Models, Biological; Photosystem II Protein Complex - metabolism; Plant Leaves - genetics; Plant Leaves - physiology; Plant Roots - genetics; Plant Stomata - physiology; Reproducibility of Results; RESEARCH PAPER; Sequence Analysis, RNA; Starch - metabolism; Stress, Physiological - genetics; Water; leaf gas exchange; morphology; RNA-Seq; gene profiling; progressive drought; purging nut; Chlorophylls; Jatropha curcas; water stress–recovery cycle; leaf and root
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/erv499

Jatropha curcas, a multipurpose plant attracting a great deal of attention due to its high oil content and quality for biofuel, is recognized as a drought-tolerant species. However, this drought tolerance is still poorly characterized. This study aims to contribute to uncover the molecular background of this tolerance, using a combined approach of transcriptional profiling and morphophysiological characterization during a period of water-withholding (49 d) followed by rewatering (7 d). Morphophysiological measurements showed that J. curcas plants present different adaptation strategies to withstand moderate and severe drought. Therefore, RNA sequencing was performed for samples collected under moderate and severe stress followed by rewatering, for both roots and leaves. Jatropha curcas transcriptomic analysis revealed shoot- and root-specific adaptations across all investigated conditions, except under severe stress, when the dramatic transcriptomic reorganization at the root and shoot level surpassed organ specificity. These changes in gene expression were clearly shown by the down-regulation of genes involved in growth and water uptake, and up-regulation of genes related to osmotic adjustments and cellular homeostasis. However, organ-specific gene variations were also detected, such as strong up-regulation of abscisic acid synthesis in roots under moderate stress and of chlorophyll metabolism in leaves under severe stress. Functional validation further corroborated the differential expression of genes coding for enzymes involved in chlorophyll metabolism, which correlates with the metabolite content of this pathway.