Plants for planting; indirect evidence for the movement of a serious forest pathogen, Teratosphaeria destructans, in Asia

Fungal diseases caused by native pathogens and pathogens introduced with planting stock have a significant impact on exotic plantation forestry in the tropics. Teratosphaeria destructans (formerly Kirramyces destructans) is a serious pathogen causing leaf, bud and shoot blight diseases of Eucalyptus spp. in plantations in the sub-tropics and tropics of south-east Asia. This pathogen was first discovered in Indonesia in 1995 and has subsequently spread to Thailand, China, Vietnam and East Timor. The biology, ecology and genetics of this important pathogen have not been explored yet. The objective of this study was, thus, to determine the genetic diversity and movement of T. destructans throughout south-east Asia using multi-gene phylogenies and microsatellite markers. Out of nine gene regions only two microsatellite markers detected a very low nucleotide polymorphism between isolates; seven other gene regions, ITS, β-tubulin, EF1-α, CHS, ATP6 and two microsatellite loci, reflected genetic uniformity. The two polymorphic molecular markers resolved six haplotypes among isolates from Indonesia and only a single haplotype elsewhere in Asia. The low diversity observed among isolates in the region of the first outbreak is as expected for a small founder population. The spread of a single clone over large distances throughout the region supports the hypothesis of spread via the human-mediated movement of germplasm

New Teratosphaeria species occurring on eucalypts in Australia

Although the first Teratosphaeria spp. with colletogloeopsis-like anamorphs were described outside of Australia, recently many new species have been described from Australia. In the present study, several new Teratosphaeria spp. were collected from infected eucalypt leaves in eastern Australia. Phylogenetic and morphological studies revealed five new taxa described here as Teratosphaeria aurantia, T. biformis, T. foliensis, T. micromaculata and T. tinara

Eucalypt plantation health in Australia

Historically in Australia eucalypts have been harvested from native forests to meet both the demand for hardwood and chips. In the last 20 years the scenario has changed and there has been a rapid expansion in the area of eucalypt plantations in Australia from less than 50 000 ha in 1985 to over 500 000 ha today. These plantations have primarily been established to supply woodchips for export. The largest areas (over 350 000 ha of predominantly Eucalyptus -ystemic) have been established in the Mediterranean climate of Western Australia, South Australia, and Victoria followed by approximately 100000 ha of predominantly E. nitens in the temperate climate of Tasmania. More recently, plantations have been established in sub-tropical Australia. Unlike exotic eucalypt plantations which flourish in the absence of native pests and diseases, the plantation estate in Australia has been faced with a multitude of indigenous pests and diseases. In addition, Australian plantations are also threatened by pathogens that have arisen on exotic eucalypt plantations but could be introduced to Australia. Faced with all these challenges one may imagine that the industry in Australia is under severe threat. However, variation in pest and disease impact is observed in taxa and provenance trials and selection of superior lines will assist in a sustainable plantation industry in the future. The major eucalyptus diseases present in Australia and those that exist overseas and pose a threat to the Australian industry will be discussed

Phylogenetic comparison of destructive eucalypt pathogens belonging to genus Phaeophleospora

Phaeophleospora species are foliar pathogens of eucalypts causing leaf blight and discoloration of the lower crowns that leads to premature defoliation, reduced growth and vigour and in some instances tree death within. There are three major Phaeophleospora pathogens: P. epicoccoides, P. eucalypti and P. destructans. P. epicoccoides is spread worldwide but the teleomorph has been found only in Indonesia and Australia. P. eucalypti is associated with serious damage particularly on E. nitens in New Zealand. P. destructans has been described from 1-3 year old E. grandis from Sumatra, Indonesia and is an aggressive pathogen that causes distortion of infected leaves and blighting of young leaves, buds and shoots throughout Asia. P. eucalypti and P. eppicocoides are found in Australia, whilst P. destructans is not and its introduction could be devastating to both native forests and plantations. The biology, ecology, genetics and pathology of these Phaeophleospora species is poorly understood. The aim of this project was to develop markers for the rapid identification of different species. To do this DNA was extracted from representative isolates of each species and PCR conducted with primers for the ITS region, β-tubulin and elongation factor and the amplicons sequenced. Multiple gene genealogies were constructed and the resultant phylogenetic tree showed that three Phaeophleospora species are closely related to each other and some Mycosphaerella sp. while P. epicoccoides DNA sequence were identical to its known anamorph Mycosphaerella sutoniae, the sequence of P. eucalypti and P. destructans were closely related to Mycosphaerella nubilosa and Coniothyrium zululense. Specific markers will now be designed to distinguish species of Phaeophleospora from each other and from other closely related fungi. These markers will be used to identify the pathogen in vitro and in planta

Phomoxins B and C: polyketides from an endophytic fungus of the genus eupenicillium

Chemical investigations of the culture broth from an endophytic fungus Eupenicillium sp. have afforded two natural products phomoxins B (1) and C (2) as well as the previously reported fungal metabolite eupenoxide (3). Compounds 1 and 2 both contain a cyclic carbonate moiety that is rare among natural products. This paper reports the full spectroscopic characterisation of phomoxins B (1) and C (2) by NMR, UV, IR and MS data. All compounds were inactive against a panel of nosocomial microbes

The Hydronomeas computational system and its application to the simulation of reservoir systems

In Australia, during the course of the last two decades, plantation area of Eucalyptus has expanded dramatically. One of the most important threats to these trees, and to the forest industries they sustain, is a complex of fungal diseases broadly treated as Teratosphaeria Leaf Blight. The aim of this review is to summarise some of the most important findings relating to Teratosphaeria spp. (previously Kirramyces) associated with leaf and shoot blight of Eucalyptus. The review spans a period of 23 years since the description of the aptly named Teratosphaeria destructans. Six species of Teratosphaeria are associated with leaf and shoot blights of Eucalyptus and these are T. destructans, T. eucalypti, T. novaehollandiae, T. pseudoeucalypti, T. viscida and T. tiwiana. With the exception of T. destructans, all of these species have been found in Australia. Based on the damage they cause, the most significant of these fungi are T. destructans, T. pseudoeucalypti and T. viscida. Teratosphaeria viscida has been found only in the tropics of eastern Australia, while T. destructans and T. pseudoeucalypti have spread globally; T. destructans throughout Asia and South Africa and T. pseudoeucalypti into South America. Factors driving the development of these diseases have included the establishment of plantations adjacent to native eucalypt forests in Australia and planting on sites not favourable to the growth of the host trees. These factors, in conjunction with a lack of selection for resistance to emerging pathogens, lack of resilience to disease in monocultures, and the movement of pathogens with planting stock and seeds around the globe have led to substantial losses. Based on the Teratosphaeria leaf blight example, it is clear that more effective forest management and more stringent biosecurity measurements will be a required to sustain eucalypt plantations globally