The role of the PXY-CLE signalling pathway in regulating cell division during wood formation in Poplar

Abstract

Focus on biomass production has increased due to the depletion of the non-renewable sources of energy. Trees are the most important source of biomass. Being perennial by nature, they produce the majority of terrestrially available biomass. Therefore, there is a vital need for a good understanding of tree development. Using Arabidopsis, previous studies in our lab have identified the influence of the receptor kinase PXY and ligand CLE signalling pathways in regulating vascular cell division. It has been shown that manipulating PXY-CLE signalling pathway increases vascular cell division in Arabidopsis. PXY-CLE functions towards increasing the stem cell population in the procambium/cambium of the Arabidopsis. In the current study, we have altered the expression of poplar homologues of PXY and CLE41 in attempt to increase cambial cell division. The poplar homologues of PXY and CLE41 genes were cloned from hybrid aspen (Populus tremula x P. tremuloides), and will be referred to as PttPXY and PttCLE41. Using tissue-specific over-expression of these PttPXY and PttCLE41 genes we were able to significantly increase the rate of tree growth and biomass above ground. Not only did the poplars exhibit a two-fold increase in the rate of wood formation, but they were also taller and possessed larger leaves compared to the untransformed controls. Together these results suggest that engineering PXY-CLE41 signalling offers an opportunity to dramatically increase commercial tree productivity.

Date of Award	31 Dec 2016
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Simon Turner (Supervisor)