Overexpression of thioredoxin m in chloroplasts alters carbon and nitrogen partitioning in tobacco

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 ch...

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Published in:Journal of experimental botany 2021-06, Vol.72 (13), p.4949-4964
Main 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
Format: Article
Language:English
Subjects:
Carbon - metabolism
Chloroplast Thioredoxins - metabolism
Chloroplasts - metabolism
Gene Expression Regulation, Plant
Nicotiana - genetics
Nicotiana - metabolism
Nitrogen - metabolism
Plants, Genetically Modified - genetics
Plants, Genetically Modified - metabolism
Research Papers
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Summary: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. 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.
ISSN:0022-0957
1460-2431
DOI:10.1093/jxb/erab193