Cress and climate change
Research into plant genetics offers hope in face of global warming
One of the major impacts of global warming is a reduction in crop yield as temperatures rise, not through extreme factors such as desertification but rather through the widely observed phenomenon that plants grow differently in a warmer environment.
Now researchers at the University of Leicester have identified a genetic factor which directly affects this temperature-related behaviour, raising the possibility that it could be ‘switched off’ in crops, allowing yields to remain steady as the atmospheric temperature continues to rise.
“Exposure of plants to high temperature results in the rapid elongation of stems and a dramatic upwards elevation of leaves,” explains Dr Kerry Franklin, Royal Society University Research Fellow and Lecturer in the Department of Biology, who led the research. “These responses are accompanied by a significant reduction in plant biomass, thereby severely reducing harvest yield.”
Funded by the Royal Society and the Biotechnology and Biological Sciences Research Council (BBSRC), the Leicester team examined the response of Arabidopsis thaliana – commonly known as wall cress – to temperatures of 28 degrees Celsius, the equivalent of a very hot summer day. While wall cress is not a crop plant, it is commonly used in biological research because it is easily cultivated, has a short life cycle of about six weeks and has a small genome which has been completely sequenced.
Long stems and raised leaves, which also occur in response to shade, are known to be caused by a plant hormone called Auxin. What Dr Franklin and her colleagues demonstrated is that the response of this hormone to high ambient temperature is regulated by a protein called Phytochrome Interacting Factor 4 (PIF4).
A mutant strain of wall cress without PIF4 did not exhibit the normal structural response to high temperatures although, interestingly, it did retain another response – early flowering – indicating that this is regulated separately. The experiment used three control groups: regular wall cress and two other mutant strains, deficient in PIF3 and PIF5. All of these displayed the expected longer stems and higher leaves.
“Identification of the mechanisms by which plants sense changes in ambient temperature remains a Holy Grail in plant biology research,” says Dr Franklin. “This study provides the first major advance in understanding how plants regulate growth responses to elevated temperature at the molecular level. It will prove fundamental in understanding the effects of global climate change on crop productivity”.
The paper ‘High temperature-mediated adaptations in plant architecture require the bHLH transcription factor PIF4’ was published in the journal Current Biology and has generated widespread media interest around the world because of its potential for addressing one of the biggest threats of climate change. Dr Franklin’s co-authors in the University of Leicester Department of Biology were Dr Trudie Allen, Ceinwen Tilley, Maria Koini and Professor Gary Whitelam, together with Liz Alvey from the John Innes Centre in Norwich and Dr Nicholas Harberd, Sibthorpian Professor of Plant Sciences at Oxford University.