Chen Stephanie H, Yap Jia-Yee S, Viler Veronica, Stehn Craig, Sandhu Karanjeet S, Percival Julie, Pegg Geoff S, Menzies Tracey, Jones Ashley, Guo Karina, Giblin Fiona R, Cohen Joel, Edwards Richard J, Rossetto Maurizio, Bragg Jason G
Research Centre for Ecosystem Resilience, Botanic Gardens of Sydney, Sydney, New South Wales, Australia.
School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Kensington, New South Wales, Australia.
Mol Ecol. 2025 Aug;34(16):e70030. doi: 10.1111/mec.70030. Epub 2025 Jul 10.
Myrtle rust is a plant disease caused by the invasive fungal pathogen Austropuccinia psidii (G. Winter) Beenken, which has a global host list of 480 species. It was detected in Australia in 2010 and has caused the rapid decline of native Myrtaceae species, including rainforest trees Rhodamnia rubescens (Benth.) Miq. (scrub turpentine) and Rhodomyrtus psidioides (G.Don) Benth. (native guava). Ex situ collections of these species have been established, with the goal of preserving remaining genetic variation. Analysis of reduced representation sequencing (DArTseq; n = 444 for R. rubescens and n = 301 for R. psidioides) showed genetic diversity is distributed along a latitudinal gradient across the range of each species. A panel of samples of each species (n = 27 for R. rubescens and n = 37 for R. psidioides) was resequenced at genome scale, revealing large historical effective population sizes, and little variation among individuals in inferred levels of deleterious load. In Rhodamnia rubescens, experimental assays (n = 297) identified individuals that are putatively resistant to myrtle rust. This highlights two important points: there are tangible pathways to recovery for species that are highly susceptible to rust via a genetically informed breeding programme, and there is a critical need to act quickly before more standing diversity is lost.
桃金娘锈病是一种由入侵性真菌病原体澳洲柄锈菌（Austropuccinia psidii (G. Winter) Beenken）引起的植物病害，该病原体的全球寄主名单上有480个物种。2010年在澳大利亚被发现，它导致了桃金娘科本土物种的迅速减少，包括雨林树木红胶木（Rhodamnia rubescens (Benth.) Miq.，矮蒲桃）和拟番樱桃（Rhodomyrtus psidioides (G.Don) Benth.，本土番石榴）。已经建立了这些物种的迁地收集库，目的是保存剩余的遗传变异。对简化基因组测序（DArTseq；红胶木n = 444，拟番樱桃n = 301）的分析表明，遗传多样性沿着每个物种分布范围的纬度梯度分布。对每个物种的一组样本（红胶木n = 27，拟番樱桃n = 37）进行了全基因组重测序，揭示了较大的历史有效种群规模，并且在推断的有害负荷水平上个体之间差异很小。在红胶木中，实验测定（n = 297）确定了可能对桃金娘锈病具有抗性的个体。这突出了两个要点：对于对锈病高度敏感的物种，通过基于遗传信息的育种计划有切实可行的恢复途径，并且迫切需要在更多现存多样性丧失之前迅速采取行动。
