Improved analysis of C4and C3photosynthesis via refinedin vitroassays of their carbon fixation biochemistry

Sharwood, Robert E.; Sonawane, Balasaheb V.; Ghannoum, Oula; Whitney, Spencer M.

doi:10.1093/jxb/erw154

Cited by 85 publications

(74 citation statements)

References 84 publications

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“…At 25°C, differences in Γ * and K o between species and photosynthetic mechanisms were non-significant, indicative that maize Rubisco presents a higher maximum catalytic turnover for the carboxylation reaction (k cat c ) than the two C 3 species, which is in agreement with recent studies (Sharwood et al, 2016a,b). The response of Rubisco kinetics to increased temperature followed trends already described in the literature, both in vivo (Brooks and Farquhar, 1985; Bernacchi et al, 2001; Walker et al, 2013) and in vitro in C 3 and C 4 species (Badger and Collatz, 1977; Jordan and Ogren, 1984; Galmés et al, 2005; Boyd et al, 2015), with increases in K c , K o , K c /K o , and Γ * (Table 1).…”

Section: Discussionsupporting

confidence: 90%

Acclimation of Biochemical and Diffusive Components of Photosynthesis in Rice, Wheat, and Maize to Heat and Water Deficit: Implications for Modeling Photosynthesis

et al. 2016

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The impact of the combined effects of heat stress, increased vapor pressure deficit (VPD) and water deficit on the physiology of major crops needs to be better understood to help identifying the expected negative consequences of climate change and heat waves on global agricultural productivity. To address this issue, rice, wheat, and maize plants were grown under control temperature (CT, 25°C, VPD 1.8 kPa), and a high temperature (HT, 38°C, VPD 3.5 kPa), both under well-watered (WW) and water deficit (WD) conditions. Gas-exchange measurements showed that, in general, WD conditions affected the leaf conductance to CO2, while growth at HT had a more marked effect on the biochemistry of photosynthesis. When combined, HT and WD had an additive effect in limiting photosynthesis. The negative impacts of the imposed treatments on the processes governing leaf gas-exchange were species-dependent. Wheat presented a higher sensitivity while rice and maize showed a higher acclimation potential to increased temperature. Rubisco and PEPC kinetic constants determined in vitro at 25°C and 38°C were used to estimate Vcmax, Jmax, and Vpmax in the modeling of C3 and C4 photosynthesis. The results here obtained reiterate the need to use species-specific and temperature-specific values for Rubisco and PEPC kinetic constants for a precise parameterization of the photosynthetic response to changing environmental conditions in different crop species.

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Section: Discussionsupporting

confidence: 90%

Acclimation of Biochemical and Diffusive Components of Photosynthesis in Rice, Wheat, and Maize to Heat and Water Deficit: Implications for Modeling Photosynthesis

et al. 2016

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“…In this decarbamylated form, the catalytic site is again prone to inhibitory binding by RuBP (i.e. the formation of an ER complex), a substantial source of Rubisco inhibition in leaves under illumination (Sharwood et al, 2016b). Under these conditions, RCA is critical for ensuring RuBP removal from ER complexes to limit the level at which they accumulate.…”

Section: Catalytic Mechanisminhibition By Rubp and Maintenance Of Rubmentioning

confidence: 99%

Engineering chloroplasts to improve Rubisco catalysis: prospects for translating improvements into food and fiber crops

2016

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494I.495II.496III.496IV.499V.499VI.501VII.501VIII.502IX.505X.506507References507 Summary The uncertainty of future climate change is placing pressure on cropping systems to continue to provide stable increases in productive yields. To mitigate future climates and the increasing threats against global food security, new solutions to manipulate photosynthesis are required. This review explores the current efforts available to improve carbon assimilation within plant chloroplasts by engineering Rubisco, which catalyzes the rate‐limiting step of CO2 fixation. Fixation of CO2 and subsequent cycling of 3‐phosphoglycerate through the Calvin cycle provides the necessary carbohydrate building blocks for maintaining plant growth and yield, but has to compete with Rubisco oxygenation, which results in photorespiration that is energetically wasteful for plants. Engineering improvements in Rubisco is a complex challenge and requires an understanding of chloroplast gene regulatory pathways, and the intricate nature of Rubisco catalysis and biogenesis, to transplant more efficient forms of Rubisco into crops. In recent times, major advances in Rubisco engineering have been achieved through improvement of our knowledge of Rubisco synthesis and assembly, and identifying amino acid catalytic switches in the L‐subunit responsible for improvements in catalysis. Improving the capacity of CO2 fixation in crops such as rice will require further advances in chloroplast bioengineering and Rubisco biogenesis.

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“…In general, PEPC/Rubisco ratio has been reported to be adjusted in order to minimize the leakage of CO2 from the bundle sheath (Kromdijk et al 2008). Interspecific variation in PEPC/Rubisco ratio was also reported by Sharwood et al (2016). The increase in PEPC/Rubisco ratio in E. crus-galli from wet habitat grown in semi-dry soil suggest an increased demand for primary CO2 fixation perhaps due to decreased availability of CO2 in the mesophyll cells.…”

Section: Discussionmentioning

confidence: 98%

Differential responses of aquatic and aerobic forms of Echinochloa crus-galli (L.) Beauv. and E. colona (L.) Link. by morpho-physiological and molecular analysis

Khedr

Serag

Shaaban

et al. 2017

Environ. Earth Ecol.

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Echinochloa crus-galli and E. colona are serious weeds around the world. Morphological and biochemical features of aquatic and aerobic forms of both species were investigated experimentally by transplanting the seedlings reciprocally between water-saturated and aerobic soils (70% field capacity). When the plants were grown in water-saturated soil, a significant decrease in tiller height was observed in E. crus-galli, but not in E. colona. Upon growing the plants in aerobic soil, internode length and spike dry weight increased significantly in E. crus-galli, but decreased significantly in E. colona. Growth under aerobic condition caused a significant increase in PEPC/Rubisco ratio, but a significant decrease was observed under water-saturated conditions. When E. crus-galli was transplanted in aerobic soil, several forms of peroxidase were upregulated. Contrarily, in E. colona peroxidase isoforms did not respond to habitat change. Gene expression of ADH in E. colona was constitutive at a fairly high level under native habitats then enhanced with reversing habitat that caused anoxic and mild drought conditions. Both species tend to grow faster under aerobic conditions by modifying the photosynthetic machinery and capacity of scavenging of reactive oxygen species. Furthermore, ADH appears to play a role in supporting growth under water-saturated conditions.

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Improved analysis of C₄and C₃photosynthesis via refinedin vitroassays of their carbon fixation biochemistry

Abstract: HighlightWe provide improved biochemical assays for key carboxylases and decarboxylases involved in C3 and C4 photosynthesis. Together with leaf age-related changes in Rubisco activation, these measurements will improve photosynthetic modelling.

Cited by 85 publications

References 84 publications

Acclimation of Biochemical and Diffusive Components of Photosynthesis in Rice, Wheat, and Maize to Heat and Water Deficit: Implications for Modeling Photosynthesis

Acclimation of Biochemical and Diffusive Components of Photosynthesis in Rice, Wheat, and Maize to Heat and Water Deficit: Implications for Modeling Photosynthesis

Engineering chloroplasts to improve Rubisco catalysis: prospects for translating improvements into food and fiber crops

Differential responses of aquatic and aerobic forms of Echinochloa crus-galli (L.) Beauv. and E. colona (L.) Link. by morpho-physiological and molecular analysis

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