moldy seeds and a growth chamber

Collins lab: Soil microbes and seed germination

New paper by a recent Bard graduate Liz Miller ’18, in collaboration between labs of Dr. Collins and Dr. Perron:

Miller, E. C., Perron, G. G., & Collins, C. D. (2019). Plant‐driven changes in soil microbial communities influence seed germination through negative feedbacksEcology and evolution9(16), 9298-9311.

As plants grow, fungal pathogens accumulate around the roots of plants.  Negative plant-soil feedbacks occur when these pathogens reduce the success of individual plants belonging to the same species. As a consequence, pathogens regulate the density of their specific plant hosts, and plants tend to grow best when their neighbor is a different plant species.

While seedlings and adult plants are known to suffer from these negative feedbacks, much less is known about the effect of species-specific pathogens on seeds. We tested whether seeds of seven different species experienced higher mortality in soils “conditioned” by plants of their own species (soils where pathogens were allowed to accumulate over time around the plant roots), versus soils conditioned by a different species. We also used metagenomics tools to identify potential pathogens driving the feedbacks.

We discovered that seeds of several grassland plant species experience negative feedbacks, i.e., the die more in their own soil than in soil of neighboring species. We also found that the putative pathogens driving these feedbacks differed depending on which species conditioned the soil a seed was buried in. Our results suggest that negative feedbacks at the seed stage may play a role in population persistence and plant diversity, and that the role of particular pathogens for driving feedbacks may depend on which plant species are in the neighborhood.