Molecular Principles to Engineer Plant Microbiomes

Download or read book Molecular Principles to Engineer Plant Microbiomes written by Mathias Johannes Eduard Edgard Ernst Voges and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The microbes that live in and on plants (the plant microbiome) are critical for plant health, and exert their influence by facilitating nutrient acquisition, regulating plant hormone levels, and helping to withstand pathogen attack. Due to these potential benefits, the plant microbiome has become an appealing target for engineering sustainable improvements in crop productivity. However, the lack of a mechanistic understanding for plant-microbiome interactions at the molecular level has impeded engineering efforts. In this dissertation, I address the role of plant-derived specialized molecules in shaping the composition of the root microbiome, and that of microbe-produced molecules in influencing plant health. Using broadly-applicable experimental platforms that allow for hypothesis-driven mechanistic studies, along with previously developed reverse genetic tools in the model plant Arabidopsis, I discovered a novel mechanism of action for coumarins (root-exuded, specialized small molecules) in assembling the microbiome of plant roots. Additionally, I describe a role for Pseudomanas-derived pyrroloquinoline quinone (a redox-active small molecule) in improving plant growth under iron-limiting conditions -- a nutrient deficiency prevalent in one-third of the world's soils. Finally, I highlight a serendipitous discovery made while engineering plants to modulate the root microbiome using opines -- unusual conjugates of two common plant metabolites that can be catabolized by select microbes. The microbes inciting the production of opines, Agrobacterium species, hijack the plant cell's splicing machinery as part of its pathogenic lifestyle. This novel finding could be exploited to improve transgene expression in plants, and to survey bacterial genomes for genes that are horizontally transferred across the kingdoms of life. These contributions, which provide mechanistic roles for both plant and microbe-derived small molecules within the phytobiome, offer concrete strategies for engineering phytobiomes to improve agricultural systems.