Item

Identification of fungal biota associated with myrtle rust infection and their potential as biocontrol agents against the disease

Date
2023-08-01
Type
Conference Contribution - published
Keywords
Fields of Research
Abstract
Myrtle rust, caused by Austropuccinia psidii, was first detected in New Zealand in 2017. Given its wide host range and the identification of the pandemic biotype in New Zealand, this pathogen is a major threat to the Myrtaceae family. This research, part of the Beyond Myrtle Rust programme, aims to develop a deeper understanding of the fungal microbiome associated with myrtle rust infection and identify hyperparasite(s) that can be developed as biocontrol agents against this pathogen. Fungal isolates were recovered from symptomatic and asymptomatic leaves from ramarama (Lophomyrtus bullata) and pōhutukawa (Metrosideros excelsa) across four sampling sites (Taranaki, Rotorua, Auckland and Christchurch). Approximately 120 fungal isolates with 2/3 being epiphytes and 1/3 being endophytes were isolated from the leaf wash and surface sterilized leaf tissue, respectively. In addition, putative hyperparasites were directly recovered from colonized rust pustules. These isolates were identified based on morphological features and sequencing of the internal transcribed spacer (ITS) region. The initial results showed more diverse fungal communities obtained from samples in native areas (Taranaki and Rotorua) compared to urban areas (Auckland and Christchurch), and more abundant epiphytic isolates compared to endophytic isolates. Species within the genera Aspergillus, Cladosporium, Epicoccum, Penicillium, Talaromyces and Trichoderma were recovered. To enable identification to species level, a range of taxonomically informative genes will be sequenced. The diversity of the fungal species recovered, and the identity of potential hyperparasites will be presented. This information will be used to select potential fungal isolates for testing for biological control activity against myrtle rust.
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