Project number 12

Investigation of the molecular mechanisms underlying the role of trehalose or trehalose-6-P in lateral root and trichome development

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 (T6P) 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 dephosporylate T6P to produce trehalose. Based on the fact that T6P is an important signaling molecule, it is likely that the Arabidopsis TPPs mainly function as local and inducible regulators of T6P levels.
In this project, we focus on the characterization of the Arabidopsis TPPI gene in the roots and leaves. Previous work on the Arabidopsis TPPI gene revealed very promising results regarding a role for this gene in lateral root development and trichome architecture. In addition, we will collaborate with the research group of Dave Jackson at the CSHL (NY-USA), which is currently investigating the role of TPPI in the development of inflorescences. Our goal is to investigate which molecular or regulatory mechanism triggers these phenotypic abnormalities. This will include cell biology, genetics and biochemistry approaches.
To gain more insight in the lateral root development and root growth, tppi mutants will be crossed with the DR5 reporter to study auxin responses. Based on preliminary research, we will cross Arabidopsis tppi mutants with some well-characterized mutants of the auxin signaling pathway as well.
The lab of Prof. Van Dijck has strong expertise in plant trehalose metabolism and generated several transgenic lines that will be used in this project. 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. A previous joint student between both labs showed that there is a link between the expression of specific trehalose biosynthesis enzymes and lateral root formation and showed that there is a link with auxin metabolism.

Keywords
Trehalose metabolism, Trehalose-6-phosphate phosphatase, lateral roots, Arabidopsis thaliana, sugar signaling

Supervisors
Patrick Van Dijck, VIB Dept. of Molecular Microbiology, KU Leuven, Leuven
Tom Beeckman, VIB Dept. of Plant Systems Biology, UGent, Gent