An international team of researchers has examined the root systems of a beautiful native WA flowering species, pincushion hakea, to determine how it has adapted to grow in phosphorus-deficient soil and better understand the plant's survival mechanisms.
Emeritus Professor Hans Lambers, from The University of Western Australia's School of Biological Sciences, collaborated with researchers from Hiroshima University, Okayama University, Hokkaido University and Yamagata University on the study published in New Phytologist.
"Plants require phosphorus to grow and survive and in environments with low levels plants need to adjust to stay alive," Professor Lambers said.
"The pincushion hakea, native to south-western Australia, has adapted to growing in soil with low levels of phosphorus by forming cluster roots – a large number of smaller rootlets extending from the root axis.
"Cluster roots increase the amount of root surface area in contact with the soil, improving its ability to extract limited resources."
Researchers examined the genes and molecular pathways responsible for cluster-root secretion and uptake in the pincushion hakea to better understand how they function at a molecular level.
The genes expressed in mature cluster roots were compared to those in adjacent lateral roots as a control.
The comparison identified 4,210 genes that were expressed at higher levels in cluster roots, providing a large number of prospective genes associated with increased cluster-root secretion and absorption.
One of the highly expressed genes in pincushion hakea cluster roots was an aluminium-activated salt transporter protein that mediated salt release into the soil and enhanced phosphorus availability.
"Improved understanding of these adaptations that allow the plants to survive could ultimately help researchers develop food crops that can thrive in nutrient-deficient soils," Professor Lambers said.
