Research

Overview – glycobiology

Our lab loves sugars! Not the kind found in candy though (well, not while we are in the lab – although #CakeFriday is a thing round here – see our Twitter feed). Instead we’re interested in how the plant makes and uses complex multi-unit sugar chains (polysaccharides). In particular, we explore the plant cell wall – a structure that surrounds every plant cell, and acts like a skeleton. It provides structural support to the plant, and protection from the environment and predators.  The plants cell wall is also really important to humans. It forms the majority of what we call plant “biomass”, and it provides us with dietary fiber, animal feed, fuel, building materials, paper, fabric (cotton) etc.  It is also a carbon-sink, since it is a store of carbon fixed during photosynthesis.

Some of the questions we are asking include “how is the plant cell wall made?”, “can we engineer a better cell wall?”, “what else does the plant do with complex sugars?”, “do plants with altered cell walls interact differently with the environment including microbes?”. More recently, we’ve become interested in how to understand this sort of biology across scale, and how to connect findings in the lab with findings in the field.

SgrassJun18_Kavitha.jpg
Kavitha hard at work in our UC Davis field, sampling engineered switchgrass (Panicum virgatum)

This research has led us down some interesting routes, including an obsession with glycosylinositolphosphorylceramides (GIPCs) – glycosylated sphingolipids which dominate the outer leaflet of the plant plasma membrane. The sugar headgroups point into the apoplast, and we have identified a number of glycosyltransferases responsible for their synthesis. We also have some interesting observations on the importance of the GIPC glycans in plant-microbe interactions (pathogens and beneficial microbes), cellulose synthesis and cell-cell adhesion… but there is lot more to do to establish mechanism.

JBEI

Within the Joint Bioenergy Institute (JBEI), our goal is to make lignocellulosic biofuels and biochemicals (fuels and chemicals made from plant biomass as a starting feedstock) an economic and environmentally sustainable possibility. It is a complex network of polysaccharides, lignin and proteins that makes up the majority of plant biomass. Our task is to make it easier and more efficient for chemical engineers to deconstruct the cell wall into simple sugars. The sugars will be fed to yeast and other micro-organisms to be fermented into ethanol, methyl-ketones, diesel, rocket fuel, plastics… whatever you and the synthetic biologists can imagine!

JBEI is a DOE bioenergy research center (BRC) funded by the Department of Energy (DOE).

Our current research uses sorghum, switchgrass, and some poplar (promising bionergy crops in the USA), as well as the model plants Arabidopsis, Brachypodium, and rice.