Repository logo
 

Overexpression of Rubisco subunits with RAF1 increases Rubisco content in maize.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Salesse-Smith, Coralie E 
Sharwood, Robert E 
Busch, Florian A 
Bardal, Viktoriya 

Abstract

Rubisco catalyses a rate-limiting step in photosynthesis and has long been a target for improvement due to its slow turnover rate. An alternative to modifying catalytic properties of Rubisco is to increase its abundance within C4 plant chloroplasts, which might increase activity and confer a higher carbon assimilation rate. Here, we overexpress the Rubisco large (LS) and small (SS) subunits with the Rubisco assembly chaperone RUBISCO ASSEMBLY FACTOR 1 (RAF1). While overexpression of LS and/or SS had no discernable impact on Rubisco content, addition of RAF1 overexpression resulted in a >30% increase in Rubisco content. Gas exchange showed a 15% increase in CO2 assimilation (ASAT) in UBI-LSSS-RAF1 transgenic plants, which correlated with increased fresh weight and in vitro Vcmax calculations. The divergence of Rubisco content and assimilation could be accounted for by the Rubisco activation state, which decreased up to 23%, suggesting that Rubisco activase may be limiting Vcmax, and impinging on the realization of photosynthetic potential from increased Rubisco content.

Description

Keywords

Chloroplasts, Immunoblotting, Molecular Chaperones, Photosynthesis, Plant Proteins, Plants, Genetically Modified, Ribulose-Bisphosphate Carboxylase, Zea mays

Journal Title

Nature Plants

Conference Name

Journal ISSN

2055-026X
2055-0278

Volume Title

4

Publisher

Palgrave Macmillan Ltd.
Sponsorship
This research was supported by the Agriculture and Food Research Initiative from the National Institute of Food and Agriculture, US Department of Agriculture, under award number 2016-67013-24464. Travel to the Australian National University was supported by the Mario Einaudi Center for International Studies, International Research Travel Grant at Cornell University.