A project undertaken at The University of Melbourne, and supervised by Edwin Lampugnani.
Drought is one of the most severe abiotic stresses that affects the health, livelihood, and food security of the world. With climate change, it is expected that the world will experience more intense drought conditions than ever before. The hotter and drier conditions will challenge the agricultural industry and food security if the crop plants that we eat cannot adapt to the rapidly changing weather conditions.
Thankfully, plants already possess many tools to withstand drought stress. Drought tolerance can be conferred by a combination of different chemical and physiological responses, including cell wall modification.
Plant cell walls are made up of many different types of sugars called polysaccharides and changing the composition of these sugars changes the physical properties of wall and thus the plant. One specific type of polysaccharide called arabinan is thought to play an important role in drought and desiccation tolerance because elevated levels of this polysaccharide in the wall are often linked to increased cell wall flexibility.
The ability of plant cell walls to stretch is a critical adaption required for desiccation tolerance in plants as it can avoid cell wall breakage and allow cells to withstand extreme desiccation. Although arabinan may be playing an important role in drought tolerance, the proteins involved in its molecular biosynthetic pathway are yet to be confirmed through biochemical activity characterisation.
An early diverging land plant group called liverworts have several species that are desiccation tolerant. Liverworts possess a cell wall that contain predominantly the same types of polysaccharides as flowering plants, but their genome is much simpler in comparison as there are reduced levels of genetic redundancy. Indeed, the liverwort model organism Marchantia polymorpha possess only two candidate genes that are likely to be involved in arabinan biosynthesis, making it an ideal system to study the genetic mechanism behind the synthesis of this polysaccharide.
This project aims to test if increased cell wall arabinan is a conserved strategy for drought tolerance in plants and will also attempt to identify the genetic and molecular process involved in arabinan biosynthesis.