Plant Autoimmunity Affects Fertility

U.S. and German plant biologists have found an autoimmune response caused by a small number of genes can be a barrier to producing viable offspring.

The scientists at the Max Planck Institute for Developmental Biology in Tubingen, Germany, and the University of North Carolina at Chapel Hill, studying Arabidopsis thaliana (thale cress) identified a phenotype that, when paired together from a male and female, produced plants that survived only long enough to produce a few leaves, then died. That’s a phenomenon called hybrid necrosis. The plants, the scientists said, resembled what would result from a mortal infection, despite the absence of a pathogen.

The researchers said their finding presents a new theory in species development: two plants of the same species fail to reproduce not because of infestation or infection from an outside organism nor from problems with reproductive organs.

If two otherwise healthy members of a species cannot produce progeny, they’re on a track toward no longer being members of the same species, said University of North Carolina Professor Jeff Dangl, This could be a very early event in what will, over time, lead to speciation.

The study appears in the Sept. 4 issue of PLoS Biology.