New understanding of plant growth brings promise of tailored products for industry

Scientists have identified new steps in the way plants produce cellulose, the component of plant cell walls that provides strength, and forms insoluble fibre in the human diet.

The findings may lead to improved production of cellulose and guide plant breeding for specific uses such as wood products and cellulosic ethanol fuel, which is estimated to have roughly 85 per cent less greenhouse gas emissions than fossil fuel sources.

Published in the journal Nature Communications, the work was conducted by an international team of scientists led by the University of Melbourne and the University of Cambridge.

The research identified several proteins that are essential in the assembly of the protein machinery that makes cellulose, said Professor Staffan Persson from the University of Melbourne, Australia.

“We found that these assembly factors control how much cellulose is made, and so plants without them can not produce cellulose very well and the defect substantially impairs plant biomass production,” he said.

“The ultimate aim of this research would be breed plants that have altered activity of these proteins so that cellulose production can be improved for the range of applications that use cellulose including paper, timber and ethanol fuels."

The newly discovered proteins are located in an intracellular compartment called the Golgi where proteins are sorted and modified.

“If the function of this protein family is abolished the cellulose synthesizing complexes become stuck in the Golgi and have problems reaching the cell surface where they normally are active,” said lead authors of the study Yi Zhang (Max-Planck Institute for Molecular Plant Physiology) and Nino Nikolovski (University of Cambridge).

“We therefore named the new proteins STELLO, which is Greek for to set in place, and deliver.”

“The findings are important to understand how plants produce their biomass,” said Professor Paul Dupree from the University of Cambridge.

“Greenhouse-gas emissions from cellulosic ethanol, which is derived from the biomass of plants, are estimated to be roughly 85 percent less than from fossil fuel sources. Research to understand cellulose production in plants is therefore an important part of climate change mitigation.

“In addition, by using cellulosic plant materials we get around the problem of food-versus-fuel scenario that is problematic when using corn as a basis for bioethanol.

“It is therefore of great importance to find genes and mechanisms that can improve cellulose production in plants so that we can tailor cellulose production for various needs.”

Previous studies by Professor Persson and Professor Dupree’s research groups have, together with other scientists, identified many proteins that are important for cellulose synthesis and for other cell wall polymers.

With the newly presented research they substantially increase our understanding for how the bulk of a plant’s biomass is produced and is therefore of vast importance to industrial applications.

Professor Persson was group leader at the Max Planck Institute of Molecular Plant Physiology until January 2015. Since then he is at the School of Biosciences at the University of Melbourne in Australia.