Calcium taxis: researchers discover important transport proteins for photosynthesis

Last updated: 6 Sep, 2018

Plant researchers at Martin-Luther-University Halle-Wittenberg (MLU) have found evidence that calcium in plants, in addition to other processes, also regulates photosynthesis. How calcium gets around the plant cell to reach its site of action was, however, unknown. Prof. Dr. Edgar Peiter and Prof. Dr. med. Sacha Baginsky identified transport proteins that fulfill this task. These 'calcium taxis' are essential for efficient photosynthesis, and thus for the growth of plants. The researchers reported their findings in a paper published in New Phytologist. They aim to clarify the significance that these transport proteins have in crops in a follow-up project.

Arabidopsis thaliana. Via Flickr; CC BY-NC-SA 2.0

Photosynthesis uses carbon dioxide and water to produce high-energy biomolecules and oxygen using light energy. It is a central physiological process in plants and the basis of life on earth. Changing a part in this biological machinery can bring far-reaching changes. "It is a common misconception that it has already been understood in all its facets – especially its regulatory mechanisms are far from being all decoded," says Prof. Dr. med. Sacha Baginsky from the Institute of Biochemistry and Biotechnology.

This is especially true for the calcium-dependent signal line. In all organisms, calcium regulates cellular processes by binding to specific proteins, which changes their function. With their project, which was funded within the framework of the Collaborative Research Center 648 "Molecular Mechanisms of Information Processing in Plants", the researchers from Halle were able to show that calcium also decisively influences the photosynthesis of the model plant thale cress. Above all, the question of how the plant manages to transport the calcium involved in the metabolism to its site of action in the chloroplasts, was previously unclear.

Subcellular localization of BICAT1‐EYFP and BICAT2‐EYFP in mesophyll protoplasts. Arabidopsis mesophyll protoplasts were transiently transformed with pART7:BICAT1:EYFP or pART7:BICAT2:EYFP and investigated by confocal microscopy.

Calcium plays a crucial role in photosynthesis – it is essential for water splitting. In addition, it reacts with enzymes and thus also influences the sugar metabolism of plants. "If you understand the regulation of these complicated physiological processes, you can try to optimize them," says Prof. Dr. med. Edgar Peiter from the Institute of Agricultural and Nutritional Sciences with a view to a potential practical application of these findings. "Growth, yield and tolerance to stress from environmental factors such as drought may be influenced by it."

A four-year follow-up project will investigate whether the transport proteins are as important in crops such as cereals and sugar beet as they are in thale cress, and whether they can be used to improve the productivity and stress tolerance of these crops.

Read the paper: Frank, J., Happeck, R., Meier, B., Hoang, M. T., Stribny, J., Hause, G., Ding, H., Morsomme, P., Baginsky, S. and Peiter, E. (2018) Chloroplast‐localized BICAT proteins shape stromal calcium signals and are required for efficient photosynthesis. New Phytologist. doi: 10.1111/nph.15407

Taken from a press release.