Ido Bar

Araucaria heterophylla is a widely planted evergreen ornamental species in urban and coastal landscapes worldwide. Increasingly, these trees have been exhibiting stress symptoms, including canopy dieback, browning of foliage tips, defoliation, and reduced needle length. Previous research has shown that these symptoms may be the result of predisposing abiotic stressors, such as extreme weather events, soil compaction, and proximity to urban infrastructure. Building on this, the present study examines the trees’ foliar fungal communities and potential pathogens. Thirty-two (32) mature A. heterophylla trees of varying health growing on the foreshores of Gold Coast, Australia, were selected for isolation of fungi from foliage samples. Sixteen fungal species from ten families were identified. Neofusicoccum luteum , the most commonly represented species and previously unreported in A. heterophylla , was isolated from eight trees (25%) and selected for six-week-long pathogenicity testing under controlled glasshouse conditions. To assess pathogenicity, forty two-year-old trees were inoculated with either N. luteum or sterile agar (control). Half of these trees received limited water, and the other half was watered regularly. The infection rate exceeded 90%, and lesions developed in both groups, but lesions in the control groups were significantly smaller ( p < 0.05) than in trees inoculated with N. luteum . Re-isolation at the end of the pathogenicity tests had a higher success rate in drought-affected trees (75%) despite the smaller size of the lesions. Although no mortality occurred, trees inoculated with the pathogen were significantly ( p < 0.05) shorter than the control trees under the regular water conditions. These results suggest that N. luteum may contribute to A. heterophylla decline and reduced growth rate, but is unlikely to be the sole causal agent and is unable to kill a tree rapidly. Strategies for improving A. heterophylla health and management emerging from this study include the need for: (a) supplem.entary irrigation during prolonged drought to prevent the pathogen from entering through damaged bark; and (b) consistent tree health monitoring.

Extracellular vesicles produced by pathogenic organisms play a role in host recognition and invasion across kingdoms, including fungi interacting with their plant hosts. Little is known about EVs from phytopathogenic fungi compared to human fungal pathogens. Ascochyta rabiei is an endemic and widespread necrotrophic ascomycete fungus that causes a significant impact on chickpea production. The presence of EVs generated by A. rabiei during the invasion of chickpea has not previously been reported. Here, A. rabiei EVs were identified and isolated from liquid fungal broth cultures, both with and without host, using optimized ultracentrifugation and filtration techniques. Nanoparticle tracking analysis, transmission electron microscopy, and mass spectrometry revealed 40–200 nm cup‐shaped, double‐membraned structures. Protein cargo analysis showed significant variations depending on host presence, affecting EV production, size, and composition. The cargo included proteins involved in vesicle transport, basic cellular and oxidation/reduction‐related processes, as well as pathogenesis. Some were upregulated in the presence of the host, likely facilitating immune modulation, plant defence alteration, or pathogen establishment. These findings highlight the presence and functional importance of A. rabiei EVs in the interaction with and invasion of chickpea. Future research should concentrate on characterizing EVs under various growth circumstances and confirming fungal‐specific EV markers. Summary: This study presents the first characterization of extracellular vesicles (EVs) produced by Ascochyta rabiei , a major phytopathogenic fungus affecting chickpea. An optimized ultracentrifugation and filtration‐based isolation method enabled efficient EV recovery without reliance on specialized equipment. Comprehensive proteomic analysis revealed that EV production, size distribution, and protein composition were modulated by the presence of the host. Identified EV‐associated proteins were linked to virulence, oxidative stress response, cell wall modification, and effector functions, suggesting a role in host‐pathogen interactions. These findings advance the current understanding of fungal EVs in plant infection processes and establish a foundation for future studies investigating their functional significance in pathogenesis.

Sexual maturation is a critical developmental transition in abalone, yet its molecular basis remains unclear. Understanding the mechanisms underlying maturation is essential for improving the yield and quality of aquaculture production. This study employed transcriptomic analysis to identify key genes involved in the early stages of sexual maturation in the greenlip abalone ( Haliotis laevigata ), a commercially and ecologically important species native to Australia. Among the most significantly differentially expressed genes were members of the 5-hydroxytryptamine receptor, cytochrome P450, and HSP70 families, which are associated with neuroendocrine signalling, steroid metabolism, and cellular stress response, respectively. Gene regulatory network analysis further predicted their upstream and downstream interactions, suggesting potential signalling pathways that may coordinate reproductive initiation. These findings provide new insights into the molecular mechanisms underlying early maturation in abalone and establish a foundation for future functional investigations.

Marteilia sydneyi , an ascetosporean parasite, is the causative agent of Queensland Unknown (QX) disease in Saccostrea glomerata . QX disease outbreaks often lead to high mortality rates and considerable population losses. Investigating host/parasite interactions at a molecular level is imperative to better understand how S. glomerata mounts immune defences, and to explore whether M. sydneyi evades host responses. This study aims to investigate S. glomerata’s response to M. sydneyi infection through differential gene expression analysis to uncover immune mechanisms and potential markers for resistance. RNA sequencing and differential gene expression analysis revealed widespread transcriptional changes between infected and non-infected oysters. Genes encoding proteins involved in pathogen recognition and immune response signalling, such as galectin-4-like and G-protein coupled receptors, were significantly differentially expressed in S. glomerata infected with M. sydneyi , suggesting involvement in the host’s immune responses. Moreover, the upregulation of cytochrome P450 family genes indicate increases in the host’s detoxification processes and metabolic pathways, a possible response to infection-induced stress. However, extracellular superoxide dismutase, a gene previously implicated in the oxidative stress response to pathogens, was significantly downregulated, suggesting potential suppression of oxidative burst defence mechanisms. These results reveal the complex nature of S. glomerata’s response to M. sydneyi infection, and possible suppression or evasion of host defences by the parasite. The study also identifies multiple genes that likely play crucial roles in the molecular responses and defence mechanisms of S. glomerata to M. sydneyi infection. The identification of these genes provides potential target genes for future studies and possible biomarkers for breeding QX - resistant oyster lines. Highlights: M. sydneyi infection induces a large transcriptional response in S. glomerata Upregulation of pathogen recognition genes, including galectins, occurs in infected tissues. Lack of differential expression of apoptosis genes suggests other immune strategies. G-protein coupled receptor pathways were upregulated, indicating species-specific responses. Results suggest possible suppression of host immune responses by the parasite.

Ascochyta blight caused by the ascomycete Ascochyta rabiei poses a major biotic threat to chickpea (Cicer arietinum) industries worldwide and incurs substantial costs to the Australian multimillion-dollar chickpea industry in both disease control and yield loss. The fungus was introduced to Australia in the 1970s from an unknown source population and, within a few decades, successfully established in all Australian agroecological chickpea-growing regions. Although genetically highly clonal, a broad range of phenotypic variation in terms of aggressiveness exists among the Australian A. rabiei isolates. More recently, highly aggressive isolates capable of causing severe disease symptoms on moderate to highly resistant chickpea cultivars have increased in frequency. To identify genetic loci potentially associated with A. rabiei aggressiveness on Australian chickpea cultivars, we performed deep genome sequencing of 230 isolates collected from a range of agroecological chickpea-growing regions between 2013 and 2020. Population genetic analyses using genome-wide SNP data identified three main clusters of genetically closely related isolates in Australia. Phylogenetic analyses showed that highly aggressive phenotypes developed multiple times independently throughout the phylogeny. The results point to a minor contribution of multiple genetic regions and most likely epigenomic variations to aggressiveness of A. rabiei isolates on Australian chickpea cultivars.

Dingoes are culturally and ecologically important free-living canids whose ancestors arrived in Australia over 3,000 B.P., likely transported by seafaring people. However, the early history of dingoes in Australia—including the number of founding populations and their routes of introduction—remains uncertain. This uncertainty arises partly from the complex and poorly understood relationship between modern dingoes and New Guinea singing dogs, and suspicions that post-Colonial hybridization has introduced recent domestic dog ancestry into the genomes of many wild dingo populations. In this study, we analyzed genome-wide data from nine ancient dingo specimens ranging in age from 400 to 2,746 y old, predating the introduction of domestic dogs to Australia by European colonists. We uncovered evidence that the continent-wide population structure observed in modern dingo populations had already emerged several thousand years ago. We also detected excess allele sharing between New Guinea singing dogs and ancient dingoes from coastal New South Wales (NSW) compared to ancient dingoes from southern Australia, irrespective of any post-Colonial hybrid ancestry in the genomes of modern individuals. Our results are consistent with several demographic scenarios, including a scenario where the ancestry of dingoes from the east coast of Australia results from at least two waves of migration from source populations with varying affinities to New Guinea singing dogs. We also contribute to the growing body of evidence that modern dingoes derive little genomic ancestry from post-Colonial hybridization with other domestic dog lineages, instead descending primarily from ancient canids introduced to Sahul thousands of years ago.

Consumer trends towards nutrient-rich foods are contributing to global increasing demand for tropical fruit. However, commercial cultivars in the breeding pipeline that are tailored to meet market demand are at risk of possessing reduced fruit flavour qualities. This stems from recurrent prioritised selection for superior agronomic traits and not fruit flavour, which may in turn reduce consumer satisfaction. There is realisation that fruit quality traits, inclusive of flavour, must be equally selected for; but currently, there are limited tools and resources available to select for fruit flavour traits, particularly in tropical fruit species. Although sugars, acids, and volatile organic compounds are known to define fruit flavour, the specific combinations of these, that result in defined consumer preferences, remain unknown for many tropical fruit species. To define and include fruit flavour preferences in selective breeding, it is vital to determine the metabolites that underpin them. Then, objective quantitative analysis may be implemented instead of solely relying on human sensory panels. This may lead to the development of selective genetic markers through integrated omics approaches that target biosynthetic pathways of flavour active compounds. In this review, we explore progress in the development of tools to be able to strategically define and select for consumer-preferred flavour profiles in the breeding of new cultivars of tropical fruit species.