首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Overexpression of BUNDLE SHEATH DEFECTIVE 2 improves the efficiency of photosynthesis and growth in Arabidopsis
Authors:Florian A Busch  Jun Tominaga  Masato Muroya  Norihiko Shirakami  Shunichi Takahashi  Wataru Yamori  Takuya Kitaoka  Sara E Milward  Kohji Nishimura  Erika Matsunami  Yosuke Toda  Chikako Higuchi  Atsuko Muranaka  Tsuneaki Takami  Shunsuke Watanabe  Toshinori Kinoshita  Wataru Sakamoto  Atsushi Sakamoto  Hiroshi Shimada
Abstract:Bundle Sheath Defective 2, BSD2, is a stroma‐targeted protein initially identified as a factor required for the biogenesis of ribulose 1,5‐bisphosphate carboxylase/oxygenase (RuBisCO) in maize. Plants and algae universally have a homologous gene for BSD2 and its deficiency causes a RuBisCO‐less phenotype. As RuBisCO can be the rate‐limiting step in CO2 assimilation, the overexpression of BSD2 might improve photosynthesis and productivity through the accumulation of RuBisCO. To examine this hypothesis, we produced BSD2 overexpression lines in Arabidopsis. Compared with wild type, the BSD2 overexpression lines BSD2ox‐2 and BSD2ox‐3 expressed 4.8‐fold and 8.8‐fold higher BSD2 mRNA, respectively, whereas the empty‐vector (EV) harbouring plants had a comparable expression level. The overexpression lines showed a significantly higher CO2 assimilation rate per available CO2 and productivity than EV plants. The maximum carboxylation rate per total catalytic site was accelerated in the overexpression lines, while the number of total catalytic sites and RuBisCO content were unaffected. We then isolated recombinant BSD2 (rBSD2) from E. coli and found that rBSD2 reduces disulfide bonds using reductants present in vivo, for example glutathione, and that rBSD2 has the ability to reactivate RuBisCO that has been inactivated by oxidants. Furthermore, 15% of RuBisCO freshly isolated from leaves of EV was oxidatively inactivated, as compared with 0% in BSD2‐overexpression lines, suggesting that the overexpression of BSD2 maintains RuBisCO to be in the reduced active form in vivo. Our results demonstrated that the overexpression of BSD2 improves photosynthetic efficiency in Arabidopsis and we conclude that it is involved in mediating RuBisCO activation.
Keywords:   Arabidopsis thaliana     BSD2  disulfide bonds  oxidative stress  protein disulfide reductase  redox  RuBisCO  Zn finger domain
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号