An exploration of the molecular signals and their effects on the belowground interaction between Eucalyptus grandis and soil fungi of different lifestyles

Abstract

The belowground interaction of roots with different microbes largely influences a plants' survival and performance and their adaptability towards abiotic stresses. Understanding how plants foster beneficial interactions with mutualistic microbes while defending against the invasion of pathogenic microbes has become one of the major focuses in plant research. The interaction between plants and soil microbes are regarded to be largely mediated by the exchange of molecular signals between the two parties. Both plants and soil microbes exude a mixture of compounds including peptides, nuclei acids, sugars, organic acids, and other metabolites, but little is known about the chemical identities and the functions of these compounds on plant-microbial interactions. Currently, a few major molecular signals and their associated pathways have been found to activate the interaction between plants and mutualistic soil microbes. However, increasing evidences have pointed to the high similarity in these signaling pathways that activate mutualistic interactions and those that trigger defense responses. Given these findings, I would hypothesize that other undiscovered, or uncharacterized, molecular signals may also play roles in a plants' surveillance processes. My thesis aimed to improve our understanding of the diverse array of molecular signals that are exchanged between plants and microbes of contrasting lifestyles during the establishment of mutualistic or pathogenic symbioses. By comparing and contrasting these identified signals to each other and to those previously identified within the literature, I sought to identify novel molecular signals linked to either pathogenic or mutualistic microbial lifestyles and examined their impact on fostering plant-microbial interactions. Lastly, I sought to investigate the impact of external environmental changes on the production of these molecular signals.

Date of Award	2020
Original language	English