Determination of crop productivity and stress responses by cation homeostasis of chloroplasts
Minh Thi Thanh Hoang, Edgar Peiter
Martin Luther University Halle-Wittenberg, Institute of Agricultural and Nutritional Sciences
Photosynthesis is fundamental for growth and yield formation of crops. In this process, the cations manganese (Mn2+) and calcium (Ca2+) play crucial roles: Mn2+ catalyses the water splitting in photosystem II, whereas Ca2+ regulates many proteins involved in photosynthetic reactions and protein import. The transport and homeostasis of both cations is thus central to chloroplast functioning and the integration of the chloroplast in the cellular signalling network. We and others have recently identified a novel family of proteins related to a yeast Ca2+ transporter that are major determinants of Ca2+- and Mn2+-related functions of chloroplasts in Arabidopsis. They may thus serve as tools to manipulate those parameters in crops to improve photosynthesis, stress responses, and Mn2+ use efficiency. However, neither the occurrence of Ca2+ signals in the chloroplast, nor its equipment with Ca2+/Mn2+ transporters has been studied in any species other than Arabidopsis. This project aims to elucidate the role of this protein family in determining Ca2+- and Mn2+-related chloroplast functions in sugar beet, a dicot species that is phylogenetically distant from Arabidopsis, and in barley, a monocot.