Overexpression of thioredoxin m in chloroplasts alters carbon and nitrogen partitioning in tobacco. (8th May 2021)

• Record Type: Journal Article
• Authors: Ancín, María; Larraya, Luis; Florez-Sarasa, Igor; Bénard, Camille; Fernández-San Millán, Alicia; Veramendi, Jon; Gibon, Yves; Fernie, Alisdair R; Aranjuelo, Iker; Farran, Inmaculada
• Editors: Gutiérrez, Rodrigo
• Is Part Of: Journal of experimental botany. Volume 72:Number 13(2021)
• Page Start: 4949
• Page End: 4964
• Publication Date: 2021-05-08
• Subjects: Carbon metabolism -- chloroplast -- glutamine synthetase -- GS-GOGAT pathway -- nitrogen metabolism -- photorespiration -- thioredoxin; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/erab193
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract: In plants, there is a complex interaction between carbon (C) and nitrogen (N) metabolism, and its coordination is fundamental for plant growth and development. Here, we studied the influence of thioredoxin (Trx) m on C and N partitioning using tobacco plants overexpressing Trx m from the chloroplast genome. The transgenic plants showed altered metabolism of C (lower leaf starch and soluble sugar accumulation) and N (with higher amounts of amino acids and soluble protein), which pointed to an activation of N metabolism at the expense of carbohydrates. To further delineate the effect of Trx m overexpression, metabolomic and enzymatic analyses were performed on these plants. These results showed an up-regulation of the glutamine synthetase–glutamate synthase pathway; specifically tobacco plants overexpressing Trx m displayed increased activity and stability of glutamine synthetase. Moreover, higher photorespiration and nitrate accumulation were observed in these plants relative to untransformed control plants, indicating that overexpression of Trx m favors the photorespiratory N cycle rather than primary nitrate assimilation. Taken together, our results reveal the importance of Trx m as a molecular mediator of N metabolism in plant chloroplasts. Abstract : Thioredoxin m overexpression modulates carbon and nitrogen partitioning in plants by regulating the photorespiratory nitrogen cycle, where an increase of activity and stability of glutamine synthetase was shown.