The mechanism enabling infected plants to pass on immunity to their offspring is being investigated in a new research study.
The three year project will investigate the biological mechanisms underlying transgenerational immune priming, the recently discovered phenomenon of plants which experience stress generating a 'memory' which can be inherited by their descendents.
These memories are manifest as primed defence responses, which means that the offspring of plants infected by disease or pests are more resistant to these diseases or pests than their parents.
Not only can the immediate descendants of infected plants show enhanced defences, but so too can their grandchildren, and even their great-grandchildren.
Since the DNA sequence of the genes in these plants is unchanged, the most likely mechanism for the memory effect is that it is brought about by chemical modifications of chromosomes. Such modifications are reversible, allowing genetic changes which are not fixed, and which are therefore well-suited to controlling short-to medium-term responses to the environment.
“One idea that we will test during this project, is that immune priming is based on DNA methylation, a reversible chemical alteration of the genetic material that can have a profound impact on gene activity without changing the DNA sequence,” said Dr Mike Roberts, a senior lecturer at the Lancaster Environment Centre, who is leading the project.
The project, which is funded by the Biotechnology and Biological Sciences Research Council (BBSRC), will also examine the costs and benefits for plants of transgenerational immune priming.
“Different groups of hormones regulate how plants respond to different stresses and, sometimes, these responses can work against each other,” explains Mike.
“Increased disease resistance often comes at the cost of a decrease in insect resistance, and vice versa. What we want to find out is how much transgenerational induced resistance against one form of stress impacts on resistance to other forms of stress.”
The project is a collaboration between Mike and Dr Jurriaan Ton at the University of Sheffield.