and Species Associated with Yield Decline of Pyrethrum () in Australia.

Pyrethrum () cultivation in Australia, which accounts for the majority of global production of natural insecticidal pyrethrins, is affected by a persistent yield decline which in part is caused by a complex of pathogens. and species were isolated from crown and roots of pyrethrum plants showing stunting and brown discoloration of crown tissue, and from soil adjacent to diseased plants from yield-decline-affected sites in Tasmania and Victoria, Australia. Ten known species (, , , , , , , and var.

Diversity and Pathogenicity of Species Associated with Reduced Yields of Processing Tomatoes () in Victoria, Australia.

Yield decline associated with poor crop establishment, stunting, wilting, and diminished root systems was reported in processing tomato crops in Victoria, Australia. During surveys between 2016 and 2018 species were isolated by soil baiting and by culturing from the diseased roots and collars of plants exhibiting these symptoms. Eleven species of were identified based on cultural characteristics and phylogenetic analysis with ITS, Cox-1, and Cox-2 gene sequences.

Species Causing Anthracnose of Citrus in Australia.

spp. are important pathogens of citrus that cause dieback of branches and postharvest disease. Globally, several species of have been identified as causing anthracnose of citrus.

Identification, prevalence and pathogenicity of species causing anthracnose of in Asia.

Anthracnose of chili ( spp.) causes major production losses throughout Asia where chili plants are grown. A total of 260 isolates, associated with necrotic lesions of chili leaves and fruit were collected from chili producing areas of Indonesia, Malaysia, Sri Lanka, Thailand and Taiwan.

Inheritance of breeding system in Cakile (Brassicaceae) following hybridization: implications for plant invasions.

Background And Aims: Hybridization is commonly assumed to aid invasions through adaptive introgression. In contrast, a recent theoretical model predicted that there can be non-adaptive demographic advantages from hybridization and that the population consequences will depend on the breeding systems of the species and the extent to which subsequent generations are able to interbreed and reproduce. We examined cross-fertilization success and inheritance of breeding systems of two species in order to better assess the plausibility of the theoretical predictions.

Population Structure of in Australian Pyrethrum Reveals High Evolutionary Potential.

, the causal agent of anthracnose, is an emerging pathogen of commercially grown pyrethrum () in Australia. A microsatellite marker library was developed to understand the spatio-genetic structure over three sampled years and across two regions where pyrethrum is cultivated in Australia. Results indicated that was highly diverse with a mixed reproductive mode; comprising both sexual and clonal reproduction.

Comparative genome analysis indicates high evolutionary potential of pathogenicity genes in Colletotrichum tanaceti.

Colletotrichum tanaceti is an emerging foliar fungal pathogen of commercially grown pyrethrum (Tanacetum cinerariifolium). Despite being reported consistently from field surveys in Australia, the molecular basis of pathogenicity of C. tanaceti on pyrethrum is unknown.

Chloroplast variation is incongruent with classification of the Australian bloodwood eucalypts (genus Corymbia, family Myrtaceae).

Previous molecular phylogenetic analyses have resolved the Australian bloodwood eucalypt genus Corymbia (~100 species) as either monophyletic or paraphyletic with respect to Angophora (9-10 species). Here we assess relationships of Corymbia and Angophora using a large dataset of chloroplast DNA sequences (121,016 base pairs; from 90 accessions representing 55 Corymbia and 8 Angophora species, plus 33 accessions of related genera), skimmed from high throughput sequencing of genomic DNA, and compare results with new analyses of nuclear ITS sequences (119 accessions) from previous studies. Maximum likelihood and maximum parsimony analyses of cpDNA resolve well supported trees with most nodes having >95% bootstrap support.

Paraphoma Crown Rot of Pyrethrum (Tanacetum cinerariifolium).

Pyrethrum (Tanacetum cinerariifolium) is commercially cultivated for the extraction of natural pyrethrin insecticides from the oil glands inside seed. Yield decline has caused significant yield losses in Tasmania during the last decade. A new pathogen of pyrethrum causing crown rot and reduced growth of the plants in yield decline affected fields of northern Tasmania was isolated from necrotic crown tissue and described as Paraphoma vinacea.

Hybridization can facilitate species invasions, even without enhancing local adaptation.

The founding population in most new species introductions, or at the leading edge of an ongoing invasion, is likely to be small. Severe Allee effects-reductions in individual fitness at low population density-may then result in a failure of the species to colonize, even if the habitat could support a much larger population. Using a simulation model for plant populations that incorporates demography, mating systems, quantitative genetics, and pollinators, we show that Allee effects can potentially be overcome by transient hybridization with a resident species or an earlier colonizer.

IMA Genome-F 4: Draft genome sequences of Chrysoporthe austroafricana, Diplodia scrobiculata, Fusarium nygamai, Leptographium lundbergii, Limonomyces culmigenus, Stagonosporopsis tanaceti, and Thielaviopsis punctulata.

The genomes of Chrysoporthe austroafricana, Diplodia scrobiculata, Fusarium nygami, Leptographium lundbergii, Limonomyces culmigenus, Stagonosporopsis tanaceti, and Thielaviopsis punctulata are presented in this genome announcement. These seven genomes are from endophytes, plant pathogens and economically important fungal species. The genome sizes range from 26.

Identification of the MAT1 locus in Stagonosporopsis tanaceti, and exploring its potential for sexual reproduction in Australian pyrethrum fields.

Stagonosporopsis chrysanthemi, S. inoxydabilis, and S. tanaceti are closely related Ascomycetes associated with ray blight of the Asteraceae.

Rapid Changes in the Genetic Composition of Stagonosporopsis tanaceti Population in Australian Pyrethrum Fields.

A novel set of microsatellite markers were developed and employed for geographical and temporal population analyses of Stagonosporopsis tanaceti, the cause of ray blight of pyrethrum in Australia. Genotyping of 407 isolates, using 13 markers, suggested an asexual mode of reproduction with significant linkage disequilibrium and high levels of clonality. Low geographical differentiation and widespread distribution of a few multilocus genotypes (MLGs), in the absence of airborne ascospores, suggested the role of human-mediated movement of seed as a major means of long-distance pathogen dispersal.

Chloroplast genome analysis of Australian eucalypts--Eucalyptus, Corymbia, Angophora, Allosyncarpia and Stockwellia (Myrtaceae).

We present a phylogenetic analysis and comparison of structural features of chloroplast genomes for 39 species of the eucalypt group (genera Eucalyptus, Corymbia, Angophora, and outgroups Allosyncarpia and Stockwellia). We use 41 complete chloroplast genome sequences, adding 39 finished-quality chloroplast genomes to two previously published genomes. Maximum parsimony and Bayesian analyses, based on >7000 variable nucleotide positions, produced one fully resolved phylogenetic tree (35 supported nodes, 27 with 100% bootstrap support).

Lack of genetic variation in tree ring delta13C suggests a uniform, stomatally-driven response to drought stress across Pinus radiata genotypes.

We assessed the variation in delta(13)C signatures of Pinus radiata D. Don stemwood taken from three genetic trials in southern Australia. We sought to determine the potential of using delta(13)C signatures as selection criteria for drought tolerance.

Cross-species amplification of Eucalyptus microsatellite loci.

This study examined the interspecific amplification of nuclear microsatellite loci developed mainly for eucalypts in the subgenus Symphyomyrtus across five species within the second most speciose subgenus, subgenus Eucalyptus. A set of eight to 10 loci, depending on taxon, have been identified that are highly variable and easily scored. The successful transfer of microsatellite loci to these eucalypt species sidesteps the expensive and time-consuming development of species-specific microsatellite libraries.

Analysis of a diverse global Pisum sp. collection and comparison to a Chinese local P. sativum collection with microsatellite markers.

Twenty-one informative microsatellite loci were used to assess and compare the genetic diversity among Pisum genotypes sourced from within and outside China. The Chinese germplasm comprised 1243 P. sativum genotypes from 28 provinces and this was compared to 774 P.

Development of microsatellite markers for the grapevine fungal pathogen Phaeomoniella chlamydospora.

Twenty polymorphic microsatellite markers from microsatellite-enriched genomic DNA of the grapevine fungal pathogen, Phaeomoniella chlamydospora, were developed and characterized. The markers were used to genotype isolates from Australia and from Europe/Eurasia. The number of alleles per locus ranged from two to 11.

Polybrominated diphenyl ethers and polybrominated biphenyls in Australian sewage sludge.

This paper presents a brief review of the international scientific literature of polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs) in sewage sludge and a survey of these compounds in sewage sludge from 16 Australian wastewater treatment plants (WWTPs). The SigmaPBDE mean concentration in the Australian study was 1137microgkg(-1) dry weight (d.w.

Leaf osmotic potential of Eucalyptus hybrids responds differently to freezing and drought, with little clonal variation.

Concentrations of solutes, and thus leaf osmotic potential (Psi pi), often increase when plants are subject to drought or sub-zero (frost) temperatures. We measured Psi pi and concentrations of individual solutes in leaves of 3-year-old Eucalyptus camaldulensis Dehn., E.

Dioxin-like compounds in Australian sewage sludge--review and national survey.

An Australian survey of dioxin-like compounds in sewage sludge was conducted in two parts (a) a national survey, and (b) a time-study. All sewage sludge samples analysed as part of these studies had low overall concentrations of dioxin-like compounds. Out of 37 samples, all except one, were within the reported concentration range of soil within the Australian environment.

Mechanical stability of trees under dynamic loads.

Tree stability in windstorms and tree failure are important issues in urban areas where there can be risks of damage to people and property and in forests where wind damage causes economic loss. Current methods of managing trees, including pruning and assessment of mechanical strength, are mainly based on visual assessment or the experience of people such as trained arborists. Only limited data are available to assess tree strength and stability in winds, and most recent methods have used a static approach to estimate loads.

Cyanogenesis in Eucalyptus polyanthemos seedlings: heritability, ontogeny and effect of soil nitrogen.

Cyanogenic plants release cyanide from endogenous cyanide-containing compounds (generally cyanogenic glycosides) and thus have an effective means of chemical defense. The capacity for cyanogenesis can be highly variable, even among individuals within a population. The genetic, environmental and developmental factors determining this variability are poorly understood, particularly in tree species.