Mineral nutrition in closely related C3 and C4 plants

C4 photosynthesis relies on a cell-specific localization of enzymes involved in CO₂ assimilation in bundle sheath cells or mesophyll cells. Interestingly, enzymes of nitrogen and sulfur assimilation are also differentially localized in maize and many other C4 species. While enzymes for nitrate reduction are present exclusively in the mesophyll, sulfate assimilation is specific to bundle sheath. This localization, however, could not be confirmed in C4 species of the genus Flaveria and it thus seems to be limited to C4 monocots. However, recently we found the sulfate assimilation pathway to be coordinately enriched in bundle sheath cells of Arabidopsis, opening new questions about the significance of such cell-specific localization of the pathway. In addition, within the genus Flaveria we observed a gradient with higher expression of genes for sulfate reduction and higher accumulation of reduced sulfur metabolites in C4 species than in C3 species. We are therefore interested in the the following questions:

• What are the general consequences of C4 photosynthesis for nutrient homeostasis?
• What is the role of the spatial distribution of enzymes of nitrate and sulfate assimilation in C4 leaves
  for N and S homeostasis and use efficiency?
• What are the mechanisms underlying differences in nutrient uptake and partitioning among C3 and
  C4 plants?

Key publications:

Hua L., Stevenson S. R., Reyna-Llorens I., Xiong H., Kopriva S., Hibberd J. M. (2021) The bundle sheath of rice is conditioned to play an active role in water transport as well as sulfur assimilation and jasmonic acid synthesis. Plant J. 107, 268-286.

Jobe T.O., Rahimzadeh Karvansara P., Zenzen I., Kopriva S. (2020) Ensuring nutritious food under elevated CO2 conditions: A case for improved C4 crops. Front. Plant Sci. 11, 1267.

Jobe T.O., Zenzen I., Rahimzadeh Karvansara P., Kopriva S. (2019) Integration of sulfate assimilation with carbon and nitrogen metabolism in transition from C3 to C4 photosynthesis. J Exp. Bot. 70, 4211-4221.

Gerlich S.C., Walker B.J., Krueger S., Kopriva S. (2018) Sulfate metabolism in C4 Flaveria species is controlled by the root and connected to serine biosynthesis. Plant Physiol. 178, 565-582.

Weckopp S.C., Kopriva S. (2014) Sulfur assimilation in C4 plants. Front. Plant Sci. 5, 773.

Aubry S., Smith-Unna R.D., Boursnell C.M., Kopriva S., Hibberd J.M. (2014) Transcript residency on ribosomes reveals a key role for the Arabidopsis thaliana bundle sheath in sulphur and glucosinolate metabolism. Plant J.78,659-673.

Kopriva S., Koprivova A. (2005) Sulfate assimilation and glutathione synthesis in C4 plants. Photosynth. Res. 86, 363-372.