Transcript and Metabolite Changes during the Early Phase of ABA-mediated Induction of CAM in Talinum triangulare

• Published in: Journal of experimental botany
• Main Authors: Maleckova, Eva, Brilhaus, Dominik, Wrobel, Thomas J, Weber, Andreas P M
• Format: Journal Article
• Language: English
• Published: England 24.04.2019
• Subjects: Talinum triangulare; transcriptome; crassulacean acid metabolism; abscisic acid; time course; metabolome

Crassulacean Acid Metabolism (CAM) has evolved as a water saving strategy and its engineering into crops offers an opportunity to improve their water-use efficiency. This requires a comprehensive understanding of the regulation of the CAM pathway. Here, we use the facultative CAM species Talinum triangulare as a model in which CAM can be induced rapidly by exogenous abscisic acid (ABA). RNA-sequencing and metabolite measurements were employed to analyse the changes underlying CAM induction and identify potential CAM regulators. Non-negative matrix factorisation followed by k -means clustering identified an early CAM-specific cluster and a late one, which was specific for the early light phase. Enrichment analysis revealed ABA metabolism, WRKY-regulated transcription, sugar and nutrient transport and protein degradation in these clusters. Activation of the CAM pathway was supported by up-regulation of phosphoenolpyruvate carboxylase, cytosolic and chloroplastic malic enzymes and several transport proteins as well as by increased end-of-night titratable acidity and malate accumulation. Transcription factors HSFA2, NF-YA9 and JMJ27 were identified as candidate regulators of CAM induction. With this study we promote the model species T. triangulare, in which CAM can be induced in a controlled way, enabling further deciphering of CAM regulation.