GLOBAL: Plant biomass largest renewable resource

An international multidisciplinary team of researchers from Argentina, Australia, the US, Denmark and Brazil have uncovered the key steps for controlling plant growth. The team has shown how the assembly of components of the plant cell wall regulates growth of root hairs.

Root hairs are important structures that allow plants to absorb essential nutrients and water from the soil. The research will assist in contributing to the sustainability of plant-based industries such as agriculture, horticulture and forestry.

Most plant roots are covered in fine root hairs, which seek out nutrients in the soil and increase the roots' surface area, allowing more water and nutrients to be absorbed.

The root hair is a single tubular cell that grows out from the plant's root surface and is surrounded by a wall rich in complex carbohydrates and glycoproteins. This wall surrounds the cell to strengthen it, like a building scaffold.

Without these scaffold glycoproteins and their complete sugar decorations they do not form their correct molecular shape to enable root hair growth. What controls the expression of these genes is the next important question to be addressed.

The researchers targeted genes involved in the production of wall glycoproteins in the model laboratory plant Arabidopsis. The team identified three groups of genes required for the assembly of the cell wall scaffold glycoprotein, called extension, and when the genes were prevented from functioning, the root hairs were stunted.

"The root hair is therefore very important and this work could have applications for plants growing in dry and nutrient-deficient soils as they need to optimise their nutrient and water uptake," said Professor Tony Bacic, a lead author in a paper* on the research and a member of the ARC centre and the school of botany at the University of Melbourne.

"This study enhances our fundamental understanding of the growth of plants, our major renewable resource and would not have been possible without our international collaboration through the ARC Centre of Excellence in Plant Cell Walls."

Bacic said plant cell walls comprised plant biomass which represented the world's largest renewable resource: "Plant sciences have become a major new driver of international research due to their central role as renewable sources of transport fuels, as functional foods to improve human health, and as a source of raw materials for industrial processes."

* A report of the study was published in the 17 June issue of Science.