|ZARET, MAX - University Of Minnesota|
|BAUER, JONATHAN - Miami University - Ohio|
|CLAY, KEITH - Tulane University|
Submitted to: Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/23/2021
Publication Date: 10/8/2021
Citation: Zaret, M.M., Bauer, J.T., Clay, K., Whitaker, B.K. 2021. Conspecific leaf litter induces negative feedbacks in Asteraceae seedlings. Ecology. Article e03557. https://doi.org/10.1002/ecy.3557.
Interpretive Summary: The plant microbiome, including pathogens and beneficial microbes, can have direct impacts on plant health and productivity, such as growth and yield, but can also have indirect impacts on plant-plant competition. The indirect effects of soil pathogens and mutualists has been well studied in wild plant systems, but less work has been done on aboveground pathogens and mutualists colonizing leaves, leaf litter, and stems. Researchers discovered that microbes in leaf litter can indirectly impact plant-plant competition for 6 out of 10 species tested. These results indicate that the indirect effects of pathogens and mutualists in the aboveground parts of plants are pervasive and important determinants of plant interactions in the wild, similar to the importance of soil microbes.
Technical Abstract: The plant soil feedback (PSF) framework has been instrumental in quantifying soil microbial impacts on plant fitness and mechanisms for species coexistence. The recent extension of the PSF framework to microbes associated with aboveground tissues of plants, termed here as plant phyllosphere feedbacks (PPFs), can also help determine the role of aboveground microbes as drivers of plant-plant interactions. However, experimental tests of PPFs in wild hosts is nascent and their prevalence across diverse hosts remains largely unknown. Additionally, the relationship between plant host characteristics, such as functional traits and evolutionary history, with PPFs is unclear, in contrast to a substantial body of PSF literature. To test for the prevalence and mechanisms driving PPFs across diverse hosts, plant litter from ten Asteraceae species spanning slow to fast life history strategies was used to inoculate con- and heterospecific seedlings in a full factorial experimental design. We found that four species experienced significant negative PPFs and three experienced marginally significant negative feedbacks, while the feedback estimates for all ten species were negative. However, neither plant functional traits, nor phylogenetic distance were predictive of PPFs among species pairs, suggesting that other mechanisms or traits not measured may be driving these negative PPFs. Our results indicate that negative PPFs are common among native Asteraceae species and that they may have substantial impacts on plant growth and plant-plant interactions, particularly during early plant development.