Cold acclimation and BnCBF17-over-expression enhance photosynthetic performance and energy conversion efficiency during long-term growth of Brassica napus under elevated CO2 conditions

Dahal, K.; Gadapati, W.; Savitch, L.V.; Singh, J.; Hüner, N.P.A.

Planta 236(5): 1639-1652

2012


ISSN/ISBN: 1432-2048
PMID: 22847022
DOI: 10.1007/s00425-012-1710-2
Accession: 036517774

Download citation:  
Text
  |  
BibTeX
  |  
RIS

Article/Abstract emailed within 0-6 h
Payments are secure & encrypted
Powered by Stripe
Powered by PayPal

Abstract
The effects of cold acclimation and long-term elevated CO(2) on photosynthetic performance of wild-type (WT) and BnCBF17-over-expressing line of Brassica napus cv. Westar (BnCBF17-OE) grown at either 20/16 °C (non-acclimated) or 5/5 °C (cold acclimated) and at either ambient (380 μmol C mol(-1)) or elevated (700 μmol C mol(-1)) CO(2) were studied. Compared with non-acclimated WT, the BnCBF17-OE grown at 20 °C mimicked the effects of cold acclimation on WT B. napus with respect to compact dwarf phenotype and increased rates of light-saturated CO(2) assimilation and photosynthetic electron transport. This was associated with enhanced energy conversion efficiency into biomass as assessed by decreased excitation pressure coupled to decreased dependence on non-photochemical energy dissipation for a given irradiance. Growth at elevated CO(2) decreased the light and CO(2)-saturated rates of photosynthesis by 30 % for non-acclimated WT relative to growth at ambient CO(2). This was associated with inhibition in electron transport rates (20 %), decrease in amount of rbcL (35 %) and cytosolic FBPase (70 %) and increased excitation pressure and non-photochemical quenching in elevated versus ambient CO(2)-grown non-acclimated WT. In contrast, light and CO(2)-saturated rates of photosynthesis, electron transport, excitation pressure, non-photochemical quenching and levels of rbcL, cytosolic FBPase and Lhcb1 were insensitive to growth under elevated CO(2) in BnCBF17-OE and cold-acclimated WT. Thus, BnCBF17-over-expression and cold acclimation maintain enhanced energy conversion efficiency and reduced sensitivity to feedback-limited photosynthesis during long-term growth of B. napus under elevated CO(2). Our results indicated that CBFs transcription factors regulate not only freezing tolerance but also has major whole plant effects.

Cold acclimation and BnCBF17-over-expression enhance photosynthetic performance and energy conversion efficiency during long-term growth of Brassica napus under elevated CO2 conditions