Using the liverwort Marchantia palacea as a model for functional, comparative and evolutionary studies of arbuscular mycorrhizal symbiosis

Donald Danforth Plant Science Center, Saint Louis MO

Investigators

Abstract

This project focuses on the relationship between plants and a type of fungi called arbuscular mycorrhizal (AM) fungi. These fungi assist plants, particularly those in nutrient-deficient soils, in absorbing essential nutrients. In exchange, the plants provide the fungi with sugars and fats they produce. Understanding this partnership is crucial as it not only helped plants adapt from living in water to land but is also vital for most plants today. The project's unique approach involves studying liverworts, simple plants that, despite their lack of roots, engage in this beneficial interaction with AM fungi. By investigating the fundamental mechanics of this relationship, the project offers insights into how plants adapt to different environments and the influencing factors in their interaction with AM fungi. This knowledge could enhance plant nutrition, reduce dependence on synthetic fertilizers, lower farming costs, and decrease environmental impact. The project is also committed to nurturing future scientists and promoting a wider appreciation of the role of science in shaping a sustainable future. It aims to attract both undergraduates and high school students to STEM career paths. Through various outreach and educational initiatives, the project will actively engage students and the public, ignite curiosity, and foster an appreciation for science and its potential to shape a sustainable future. The proposed research is aimed at elucidating the fundamental genetic mechanisms underlying arbuscular mycorrhizal (AM) symbiosis, a prevalent plant-microbe association that facilitates plant survival. Despite its ubiquity and significance, understanding of AM symbiosis is minimal due to the subterranean nature of this interaction and the slow pace of mutant studies in common flowering plant model systems. The project aims to identify the core set of gene functions required for AM symbiosis across all plants and test these functions in the early-diverging liverwort, Marchantia paleacea. The central hypothesis is that a conserved set of genes and cellular processes are essential for successful AM symbiosis in all plants, irrespective of their lifestyle or lineage. The research approach includes comparative phylogenomics to identify the core set of genes used by all land plants, development of a phenotyping framework for cellular and physiological assessment of AM symbiosis in Marchantia, and characterization of conserved gene requirements for a functional mutualism between Marchantia and AM fungi through mutant plant studies. This innovative approach leverages a new model system to accelerate understanding of the most impactful genes in AM symbiosis. In addition, these results can serve as a blueprint to generate principles that can be applied to a range of other important plant-microbe symbiotic interactions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.