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. In the present work, the influence of thioredoxin (Trx) m on C and N partitioning was studied 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, indicating an up-regulation of the GS-GOGAT pathway. Trx m-overexpressing plants specifically displayed increased activity and stability of glutamine synthetase in tobacco plants. Moreover, higher photorespiration and nitrate accumulation were determined in these plants relative to the untransformed control, indicating that overexpression of Trx m favors the photorespiratory N cycle rather than primary nitrate assimilation. Taken together, the combined results reveal the importance of Trx m as a molecular mediator of N metabolism in plant chloroplasts.

Nitrogen application alleviates salt stress by enhancing osmotic balance, ROS scavenging, and photosynthesis of rapeseed seedlings (Brassica napus)

“…It is a component of the main substances in crops, such as nucleic acid, protein, and chloroplast. 13 Nitrogen actively participates in a variety of physiological pathways, such as osmotic substance synthesis, 14 ROS scavenging, 15 photosynthesis regulation, 16 and so on. Ahanger et al 17 pointed out that nitrogen application could enhance the accumulation of antioxidant substances and osmolyte metabolism of wheat, and alleviate the growth inhibition caused by salt stress.…”

The emerging key role of reactive sulfur species in abiotic stress tolerance in plants

“…Activation of N metabolism by TRX has been proven in tobacco overexpressing Trx m, which exhibited reduced production of starch and soluble sugar but increased amino acid and T A B L E 1 Reports showing role of "S" species in mitigating various abiotic stress responses. protein accumulation (Ancín et al, 2021). In rice, multiple OsTrx genes have been shown to respond to multiple environmental stresses (Nuruzzaman et al, 2012).…”

“…TRX can also directly decrease ROS levels through the action of thioredoxin peroxidase (Yamawaki et al, 2003) and has been reported to play important roles in DNA and protein repair (Lu & Holmgren, 2014). Activation of N metabolism by TRX has been proven in tobacco overexpressing Trx m , which exhibited reduced production of starch and soluble sugar but increased amino acid and protein accumulation (Ancín et al, 2021). In rice, multiple OsTrx genes have been shown to respond to multiple environmental stresses (Nuruzzaman et al, 2012).…”

Canopy light distribution effects on light use efficiency in wheat and its mechanism

“…In this study, redox-related proteins also changed with the increase in row spacing. Additionally, observed redox-related proteins may be critical for maintaining the balance between C and N metabolism (Ancín et al, 2021). So, they could be good candidates for enriching the regulation network of light efficient utilization.…”