Investigation of molecular mechanisms of trehalose-6-P in lateral root development and on stomatal aperture.

Trehalose metabolism in plants is becoming a hot topic, because it affects a lot of agricultural important characteristics such as growth, stress tolerance and sugar partitioning. For instance, the intermediate molecule during its biosynthesis, trehalose-6-phosphate (T6-P) connects the sugar status with plant growth and development. However, the underlying working mechanism is not clear. The trehalose-6-phosphate phosphatase (TPP) gene family of Arabidopsis thaliana consists of 10 genes (TPPA-J), all encoding active TPP enzymes able to dephosphorylate T6-P to produce trehalose. Based on the fact that T6-P is an important signalling molecule, it is likely that the Arabidopsis TPPs mainly function as local and inducible regulators of T6-P levels. In this project, we focus on the characterization of the Arabidopsis TPPB and TPPG genes in the roots and leaves, respectively. Previous work on the Arabidopsis TPPB gene revealed very promising results regarding a role for this gene in lateral root development. Moreover, it is published for Van Dijck lab that TPPG participates in stomatal aperture. Our goal is to investigate which molecular or regulatory mechanism are behind the modification of trehalose metabolism. This will include cell biology, genetics and biochemistry approaches. Moreover, we are going to study the role of gene orthologs of AtTPPB and AtTPPG in the moss Physcomitrella patens. Results in the Van Dijck lab have shown that P. patens expresses 7 TPP enzymes, but the function of these enzymes remains to be identified. The lab of Prof. Van Dijck has strong expertise in plant trehalose metabolism and with the fransformation and phenotypic characterization of Physcomitrella. The lab of Prof. Beeckman has extensive expertise in root biology and especially in the early events resulting in the formation of lateral root formation.