101. Elevated CO2 Induces Root Defensive Mechanisms in Tomato Plants When Dealing with Ammonium Toxicity.
- Author
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Vega-Mas, Izargi, Pérez-Delgado, Carmen M., Marino, Daniel, Fuertes-Mendizábal, Teresa, González-Murua, Carmen, Márquez, Antonio J., Betti, Marco, Estavillo, José María, and González-Moro, Marıá Begonã
- Subjects
TOMATOES ,EFFECT of carbon dioxide on plants ,PLANT roots ,PLANT defenses ,EFFECT of ammonium on plants ,PLANT nutrition - Abstract
An adequate carbon supply is fundamental for plants to thrive under ammonium stress. In this work, we studied the mechanisms involved in tomato (Solanum lycopersicum L.) response to ammonium toxicity when grown under ambient or elevated CO
2 conditions (400 or 800 p.p.m. CO2 ). Tomato roots were observed to be the primary organ dealing with ammonium nutrition. We therefore analyzed nitrogen (N) and carbon (C) metabolism in the roots, integrating the physiological response with transcriptomic regulation. Elevated levels of CO2 preferentially stimulated root growth despite the high ammonium content. The induction of anaplerotic enzymes from the tricarboxylic acid (TCA) cycle led to enhanced amino acid synthesis under ammonium nutrition. Furthermore, the root transcriptional response to ammonium toxicity was improved by CO2 - enriched conditions, leading to higher expression of stressrelated genes, as well as enhanced modulation of genes related to signaling, transcription, transport and hormone metabolism. Tomato roots exposed to ammonium stress also showed a defense-like transcriptional response according to the modulation of genes related to detoxification and secondary metabolism, involving principally terpenoid and phenolic compounds. These results indicate that increasing C supply allowed the co-ordinated regulation of root defense mechanisms when dealing with ammonium toxicity. [ABSTRACT FROM AUTHOR]- Published
- 2017
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