Increased fructose 1,6-bisphosphate aldolase in plastids enhances growth and photosynthesis of tobacco plants

Abstract

The Calvin cycle is the initial pathway of photosynthetic carbon fixation, and several of its reaction steps are suggested to exert rate-limiting influence on the growth of higher plants. Plastid fructose 1,6-bisphosphate aldolase (aldolase, EC 4.1.2.13) is one of the nonregulated enzymes comprising the Calvin cycle and is predicted to have the potential to control photosynthetic carbon flux through the cycle. In order to investigate the effect of overexpression of aldolase, this study generated transgenic tobacco (Nicotiana tabacum L. cv Xanthi) expressing Arabidopsis plastid aldolase. Resultant transgenic plants with 1.4-1.9-fold higher aldolase activities than those of wild-type plants showed enhanced growth, culminating in increased biomass, particularly under high CO₂ concentration (700 ppm) where the increase reached 2.2-fold relative to wild-type plants. This increase was associated with a 1.5-fold elevation of photosynthetic CO₂ fixation in the transgenic plants. The increased plastid aldolase resulted in a decrease in 3-phosphoglycerate and an increase in ribulose 1,5-bisphosphate and its immediate precursors in the Calvin cycle, but no significant changes in the activities of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) or other major enzymes of carbon assimilation. Taken together, these results suggest that aldolase overexpression stimulates ribulose 1,5-bisphosphate regeneration and promotes CO₂ fixation. It was concluded that increased photosynthetic rate was responsible for enhanced growth and biomass yields of aldolase-overexpressing plants.

Overexpression of Plastid Transketolase in Tobacco Results in a Thiamine Auxotrophic Phenotype

“…This appears to be a unique feature of a C3-cycle enzyme, as overexpression of SBPase, FBP aldolase, or a cyanobacterial bifunctional FBPase/SBPase did not have this negative effect (Miyagawa et al, 2001;Lefebvre et al, 2005;Uematsu et al, 2012). These data together with that from the TK antisense study have revealed that plants can tolerate only small changes in the level of the endogenous TK protein; otherwise, there is an effect the pathways that receive compounds from the C3 cycle (Henkes et al, 2001).…”

Comparative Transcriptomic Approaches Exploring Contamination Stress Tolerance in Salix sp. Reveal the Importance for a Metaorganismal de Novo Assembly Approach for Nonmodel Plants

“…This is unsurprising given the stressful environment created by petroleum hydrocarbon contamination. Increased FBA has been shown to enhance both biomass yield and photosynthesis in Arabidopsis (Uematsu et al, 2012). Peroxisomal (S)-2-hydroxy-acid oxidase (GLO1 and GLO4), also in higher abundance in noncontaminated trees, are known to regulate glycolate oxidase protein levels in leaves and, more recently, suppression of glycolate oxidase has been shown to deactivate Rubisco, inhibiting photosynthesis in rice (Lu et al, 2014).…”

Overexpression of the RieskeFeS Protein Increases Electron Transport Rates and Biomass Yield

“…Transgenic studies, modeling approaches, and theoretical considerations provide evidence that increasing photosynthetic capacity is a viable route to increase the yield of crop plants (Zhu et al, 2010;Raines, 2011;Long et al, 2015;von Caemmerer and Furbank, 2016). There is now a growing body of experimental evidence showing that increasing the levels of photosynthetic enzymes in carbon metabolism results in increased photosynthesis and plant biomass (Miyagawa et al, 2001;Lefebvre et al, 2005;Raines, 2006Raines, , 2011Rosenthal et al, 2011;Uematsu et al, 2012;Simkin et al, 2015Simkin et al, , 2017Driever et al, 2017). In addition, the manipulation of photosynthetic electron transport by the introduction of the algal cytochrome c 6 protein has been shown to improve the efficiency of photosynthesis and to stimulate plant growth in low light (Chida et al, 2007).…”