Ophiostomatoid fungi associated with pine bark beetles and infested pines in south-eastern Australia, including Graphilbum ipis-grandicollis sp. nov.

Abstract

The ophiostomatoid fungi are an assemblage of ascomycetes which are arguably best-known for their associations with bark and ambrosia beetles (Curculonidae) and blue stain (sap stain) of many economically important tree species. These fungi are considered a significant threat to coniferous forests, which has resulted in numerous studies characterising the diversity of bark beetles and their ophiostomatoid associates globally. The diversity of ophiostomatoid fungi present in Australian pine plantations, however, remains largely undetermined. The aims of this study were therefore to reconsider the diversity of ophiostomatoid fungi associated with Pinus in Australia, and to establish the baseline of expected taxa found within these plantation ecosystems. To achieve this, we reviewed Australian plant pathogen reference collections, and analysed samples collected during forest health surveillance programs from the major pine growing regions in south-eastern Australia. In total, 135 ophiostomatoid isolates (15 from reference collections and 120 collected during the current study) were assessed using morphological identification and ITS screening which putatively distinguished 15 taxonomic groups. Whole genome sequencing (WGS) of representative isolates from each taxon was performed to obtain high-quality sequence data for multi-locus phylogenetic analysis. Our results revealed a greater than expected diversity, expanding the status of ophiostomatoid fungi associated with Pinus in Australia to include 14 species from six genera in the Ophiostomatales and a single species residing in the Microascales. While most of these were already known to science, our study includes seven first records for Australia and the description of one new species, Graphilbum ipis-grandicollis sp. nov.. This study also provides an early example of whole genome sequencing (WGS) approaches replacing traditional PCR-based methods for taxonomic surveys. This not only allowed for robust multi-locus sequence extraction during taxonomic assessment, but also permitted the rapid establishment of a curated genomic database for ophiostomatoid fungi which will continue to aid in the development of improved diagnostic resources and capabilities for Australian biosecurity.

A Coordinated, Risk-Based, National Forest Biosecurity Surveillance Program for Australian Forests

“…While FHS is not efficient at early detection of new alien pest incursions (Wardlaw et al, 2008), new alien pests are regularly detected. More than one third of alien pests detected in Australia over the past three decades were found through FHS or surveillance by industry staff (Carnegie and Nahrung, 2019;Trollip et al, 2021), highlighting the benefits of FHS in an overall forest biosecurity program.…”

“…The NFPSP aims to balance the resource allocation and efficacy of active and passive surveillance efficiently. In recognition that many alien forest pests are first detected during FHS (Carnegie and Nahrung, 2019;Trollip et al, 2021), the NFPSP proposes to link with existing and future FHS programs in the plantation estate.…”

Draft Genome Sequences for Three Ophiostoma Species Acquired during Revisions of Australian Plant Pathogen Reference Collections

“…The potential for global range expansions into novel ecosystems, caused by insect-mediated dispersal combined with increased human trade ( 4 ), has resulted in the regular inclusion of Ophiostoma species (and/or their vectors) on high-priority pest lists by biosecurity agencies (e.g., see references 5 and 6 ). To establish a biosecurity-focused database for Australia, we recently began the revision of ophiostomatalean specimens lodged in Australian plant pathogen reference collections ( 7 ). Here, two specimens (DAR52683 and DAR52684) were obtained from the New South Wales (NSW) Plant Pathology and Mycology Herbarium, both originally lodged as Ophiostoma piceae .…”

“…DNA extraction, library preparation, and sequencing were performed in house and followed the methods described by Trollip et al ( 7 ). Briefly, preserved specimens were successfully revived before 7-day-old cultures were used to inoculate 40-mL potato dextrose broth (Oxoid, UK).…”

Correction to: Ophiostomatoid fungi associated with pine bark beetles and infested pines in south-eastern Australia, including Graphilbum ipis‑grandicollis sp. nov

“…Following the publication of the original article (Trollip et al 2021 ), we were notified that there was a missing column at the end of the first section of Table 3, which included the genome information for one of the genomes generated in this study (Ophiostoma angusticollis – Genome Accession JADHKL000000000). Originally published table: Table 3 Genome summary statistics of representative ophiostomatoid isolates sequenced in this study Species Ceratocystiopsis Graphilbum Leptographium s. l Ceratocystiopsis sp.…”