Pathogens can significantly weaken the fitness of their hosts, sometimes even causing host mortality.
Pathogens can significantly weaken the fitness of their hosts, sometimes even causing host mortality. Yet considerable variation is found between species in their investment in disease defense. Evolutionary theory predicts that allocation costs regulate this investment, but testing this hypothesis has been challenging.
In a study published in Science, postdoctoral researcher Michael Giolai and Professor of Plant Biodiversity Anna-Liisa Laine from the University of Helsinki used open databases to identify plant defense genes and growth traits in 184 plant species. They found striking variation among plant species in the number of defense genes, which ranged from 44 to 2,256. Examples include asparagus, which has only 72 resistance genes, while one chili variety has as many as 1,095. Laine and Giolai also discovered a negative correlation between defense investment and growth traits in wild plants: the higher that the proportion of a plants’ genome is dedicated to defense genes, the lower growth potential it has.
“Our study demonstrates the significant role of allocation costs in the generation and maintenance of biodiversity. The findings also shed light on mechanisms that limit the evolution of defense,” explains Michael Giolai.
Read More: University of Helsinki
Photo Credit: Kranich17 via Pixabay
