Risk versus reward: host dependent parasite mortality rates and phenotypes in the facultative generalist Triphysaria versicolor

Authors: Honaas, Loren; JONES, SAMUEL - Pennsylvania State University; FARELL, NINA - Pennsylvania State University; KAMEROW, WILLIAM - Pennsylvania State University; ZHANG, HUITING - Pennsylvania State University; VESCIO, KATHRYN - Pennsylvania State University; ALTMAN, NAOMI - Pennsylvania State University; YODER, JOHN - University Of California, Davis; DEPAMPHILIS, CLAUDE - Pennsylvania State University

Submitted to: BMC Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2019
Publication Date: 8/1/2019
Citation: Honaas, L.A., Jones, S., Farell, N., Kamerow, W., Zhang, H., Vescio, K., Altman, N., Yoder, J., dePamphilis, C. 2019. Risk versus reward: host dependent parasite mortality rates and phenotypes in the facultative generalist Triphysaria versicolor. Biomed Central (BMC) Plant Biology. Article 334. https://doi.org/10.1186/s12870-019-1856-1.
DOI: https://doi.org/10.1186/s12870-019-1856-1

Interpretive Summary: A critical step to understanding the molecular basis of complex plant traits is knowing when to gather experimental data. We need robust experimental frameworks to discover biological processes that alter plant physiology, as well as technologies that allow us to assess plants along a time course - that is - a repeated measures approach. By measuring the same plants and tissues repeatedly, we reduce experimental noise while also efficiently managing research resources. This manuscript reports the development of a framework that includes tools to non-destructively assess plant tissues during experiments with image based analytics. We also drew conclusions from correlation with other types of data related to gene activity measurements that help us interpret plant growth patterns. This allowed us to discover easily quantifiable changes in plant appearance that previously required destructive measurements and/or were challenging to quantify. By monitoring plants through time, we can identify very early contrasts that allow us to capture biological changes with precision. This is critical to discovering biological processes that drive altered plant physiology. Our image based analytics are fast, accurate, non-invasive and directly applicable to a broad range of plant phenotypes, including necrotic peel disorders of tree fruit.

Technical Abstract: Haustorium initiation factors (HIFs) are host plant derived chemical signals, perceived by parasitic plants, that induce formation of the parasitic connection organ, the haustorium. Elucidation of this poorly understood molecular dialogue will shed light on plant-plant communication, parasitic plant physiology, and the evolution of parasitism in plants. As a starting point, we present an experimental framework that develops easily quantifiable contrasts for the ostensibly facultative generalist parasitic plant, Triphysaria versicolor as it feeds across it’s host range that spans all flowering plants. The contrasts, including variable parasite mortality when grown with known hosts, suggest the parasite can evaluate host quality and can alter its physiology accordingly. Finally, we report image based analytics that recapitulate destructive measurements via non-destructive techniques, opening the door to fine time course monitoring to catch experimental contrasts at the earliest possible time. This work sheds light on Triphysaria’s parasitic life habit and is an important step towards understanding the mechanisms of HIF perception.