Plants adapt to altitude by sensing oxygen levels

A new study led by the University of Nottingham has found that plant species adapt to the altitude where they grow by “sensing” the oxygen levels that surround them. By analyzing plants growing at both low- and high-altitude locations, the experts identified how oxygen-sensing controls the pathway of chlorophyl synthesis, permitting plants to match the levels of a toxic chemical to surrounding oxygen levels.  

Altitude is an essential part of plant ecology. At least 30 percent of plant species diversity is currently contained in the mountains. Moreover, since climate change is leading to the displacement of a large variety of wild species and crops to higher altitudes, it is essential to understand the mechanisms that allow plants to live at such heights, where oxygen levels are low.

“Altitude is a key component of ecology with different altitudes subjecting plants to changing environments, some components of which are fixed by altitude and others that are not,” said study lead author Michael Holdsworth, a professor of Crop Science at the University of Nottingham. 

“For life at high altitude, it was previously considered that plants need to adapt to many variables, including high UV light and lower temperatures usually present at high altitude, but this study is the first time that perception of atmospheric oxygen levels has been shown to be a key determinant of altitude adaptation in plants.”

Professor Holdsworth and his colleagues discovered that atmospheric oxygen level is the key determinant of altitude perception. “We define the molecular pathway through which oxygen-sensing results in an adapted phenotype and we find that distinct species of flowering plants are adapted to absolute altitude through conserved oxygen-sensing control of chlorophyll synthesis and hypoxia gene expression. Showing that this mechanism works in diverse species provides a new paradigm for plant ecology,” Professor Holdsworth explained. 

This better understanding of the genetic changes that plants go through at various heights could lead to new approaches to help plant breeders enhance the ability of crops to grow at higher attitudes – a feature which will become increasingly important as climate change advances.

The study is published in the journal Nature.

—

By Andrei Ionescu, Earth.com Staff Writer