Evolutionary history of hosts can predict plants’ susceptibility to pathogens

Powdery mildew is a fungal disease found worldwide and is particularly toxic to plants within the sunflower family. Similar to a majority of other invading pathogens, powdery mildew is underexplored, and learning how it influences hosts can allow producers to make more informed decisions and, thus, safeguard their crops.

Author and plant pathologist Michael Bradshaw with sunflowers. Image Credit: Michael Bradshaw.

Researchers from the University of Washington and the University of Central Florida inoculated a total of 126 plant species in the Sunflower family with powdery mildew and grew as many as 500 plants from seeds gathered from the wild and supplied by the USDA germplasm network.

Through this large-scale analysis, the team was able to quantify the susceptibility of numerous plants to powdery mildew disease.

We observed that the amount of disease present on a host can be dependent on where that host lies on the tree of life—that is, the evolutionary history of a host can predict how susceptible that host is to disease.”

Michael Bradshaw, Plant Pathologist, University of Washington

The researchers also determined common plant characteristics, like chlorophyll content, trichome density, and biomass, and observed that none of these traits were linked to the disease, underlining the insignificance of the commonly assessed traits of host plants in the severity of powdery mildew disease and further indicating the role of evolutionary history in plant susceptibility to the disease.

Any tools we can use to predict the severity of a disease can be valuable and improve management guidelines. Especially with fungal pathogens, where there is often a large lag time between the introduction of a pathogen and the formation of an epidemic. I am hopeful that this research could spur future work and provide ideas and techniques for other researchers studying the evolution of disease.”

Michael Bradshaw, Plant Pathologist, University of Washington

This study offers data on sunflower plant species that are impervious to powdery mildew disease, which can benefit breeding programs. Bradshaw also believes that this analysis will stimulate other research works that extract the genome of various species of plants involved to possibly identify the genes that contribute to this resistance.