The molecular dialogue between Eucalyptus grandis and the myrtle rust pathogen, Austropuccinia psidii

Abstract

Eucalypts are widely cultivated due to their significant wood quality and rapid growth, rendering them one of the most economically valuable forest plantation crops. Eucalyptus species are threatened by various emerging pests and pathogens, affecting the sustainability of our forest plantations while simultaneously posing a threat to the biodiversity of their natural range. Eucalyptus grandis is highly susceptible to Austropuccinia psidii, a biotrophic rust pathogen causing myrtle rust on approximately 480 species within 86 genera of the Myrtaceae family. With a worldwide distribution and broad host range, this pathogen is considered a global pandemic and extensive research has been conducted to elucidate the molecular mechanisms that govern the interaction between this pathogen and its hosts. The constitutive overexpression of resistance-related genes in Eucalyptus grandis are shown to play significant roles in resistance against A. psidii. However, despite recent studies on this interaction, further investigations into E. grandis host responses and in planta A. psidii pathogenic responses are required to unravel the molecular dialogue that exists in this pathosystem. Understanding these molecular interactions may lead to improved breeding strategies and engineering of resistance against A. psidii.