Reversible Burst of Transcriptional Changes during Induction of Crassulacean Acid Metabolism in Talinum triangulare

To examine the effects of day length on the induction of crassulacean acid metabolism (CAM) by drought in the tropical species, Talinum triangulare (Jacq.) Willd. (Portulacaceae), plants were subjected to drought under different photoperiods. Nocturnal acid accumulation was 52 µmol H+··g-1 fresh mass (FM) in plants grown under a 10 h light : 14 h dark photoperiod and 76 µmol H+·g-1 FM in plants grown under 13 h light : 11 h dark, whereas it was only 10 µmol H+·g-1 FM in plants grown under 18 h light : 6 h dark. Plants were subjected to drought under short days and under short days with a night interruption of 1.5 h white light, aiming to simulate a long day, while minimally affecting daily carbon balance. Only droughted plants under normal short days accumulated acids during the night. Absence of CAM could not be attributed to differences due to photoperiod in either biomass allocation, chlorophyll content, or leaf water content. Photoperiod did not significantly affect fecundity in watered plants, whereas drought markedly reduced fecundity in plants with night interruption relative to plants under normal short days. Reproductive effort, calculated as seeds per gram leaf, was significantly higher in droughted plants under normal short days and watered plants with and without night interruption than in droughted plants with night interruption.Key words: CAM, crassulacean acid metabolism, drought, fecundity, induction, photoperiod, reproductive effort, reproduction, Talinum triangulare

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Transcript and metabolite changes during the early phase of abscisic acid-mediated induction of crassulacean acid metabolism in Talinum triangulare

Journal of Experimental Botany ◽

10.1093/jxb/erz189 ◽

2019 ◽

Vol 70 (22) ◽

pp. 6581-6596 ◽

Cited By ~ 4

Author(s):

Eva Maleckova ◽

Dominik Brilhaus ◽

Thomas J Wrobel ◽

Andreas P M Weber

Keyword(s):

Abscisic Acid ◽

Crassulacean Acid Metabolism ◽

Acid Metabolism ◽

Enrichment Analysis ◽

Titratable Acidity ◽

Abscisic Acid Metabolism ◽

Use Efficiency ◽

Cam Regulation ◽

Cam Species ◽

Talinum Triangulare

Abstract 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. RNA sequencing and metabolite measurements were employed to analyse the changes underlying CAM induction and identify potential CAM regulators. Non-negative matrix factorization 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 abscisic acid 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. The 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.

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A relationship between fecundity, survival, and the operation of crassulacean acid metabolism in Talinum triangulare

Canadian Journal of Botany ◽

10.1139/b98-136 ◽

1998 ◽

Vol 76 (11) ◽

pp. 1908-1915 ◽

Cited By ~ 2

Author(s):

María Angélica Taisma ◽

Ana Herrera

Keyword(s):

Life History ◽

Life Table ◽

Water Deficit ◽

Crassulacean Acid Metabolism ◽

Reproductive Effort ◽

Acid Metabolism ◽

Significant Rise ◽

Acid Accumulation ◽

Nocturnal Acid Accumulation ◽

Talinum Triangulare

In plants of the perennial, deciduous herb Talinum triangulare, crassulacean acid metabolism (CAM) is induced by drought; therefore, CAM may be an adaptation to water deficit in this species. The present study was undertaken to determine the effects of water deficit on fecundity and CAM in plants of T. triangulare. Plants were grown from seed in the greenhouse and the life table was constructed with dynamic cohorts. CAM was induced by drought in plants as young as 45 days old, and its induction was associated with a significant rise in fecundity; values of survival beta mean fecundity by age-class were 30-50% higher in plants subjected to drought than in control plants due to a rise in fecundity. Plants subjected to drought produced more and lighter seeds, which germinated faster than their watered controls. These characteristics could be advantageous for a colonizing species such as T. triangulare. Plants obtained from the germination of seeds of plants subjected to drought did not show higher values of nocturnal acid accumulation when subjected to drought than the droughted offspring of watered plants but they showed higher survival and an earlier and higher reproductive effort than plants obtained from the germination of seeds of watered plants. The fact that values of survival beta mean fecundity were higher in plants subjected to drought than in watered plants suggests, within the context of the life history, that characters associated with the CAM syndrome may be adaptive.Key words: fitness, inducible CAM, life table.

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