Phytophthora austrocedrae sp. nov., a new species associated with Austrocedrus chilensis mortality in Patagonia (Argentina)

Greslebin, Alina Gabriela; Hansen, E. M.; Sutton, Wendy

doi:10.1016/j.mycres.2007.01.008

Cited by 89 publications

(97 citation statements)

References 9 publications

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“…Outbreaks of Phytophthora lateralis, the causal agent of root disease in Port Orford Cedar (Chamaecyparis lawsoniana) in the Pacific North-west (Hansen et al 2000), has been reported from dying C. lawsoniana in Europe (Hansen et al 1999). In South America two very different Phytophthora diseases have emerged: Phytophthora austrocedrae causes root disease and extensive mortality through the root infection of Austrocedrus chilensis (Mal del Ciprés) on the eastern slopes of the Andes in Patagonia (Greslebin et al 2007), and Phytophthora pinifolia causes a shoot blight of exotic P. radiata plantations (Daño Foliar del Pino) on the moist western slopes of the Chilean Andes (Durán et al 2008). Elsewhere, P. austrocedraehas been reported as a serious pathogen of juniper (Juniperus communis) in the United Kingdom (Green et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Distribution and diversity of Phytophthora across Australia

Burgess

White

McDougall

et al. 2017

Pac. Conserv. Biol.

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The introduction and subsequent impact of Phytophthora cinnamomi within native vegetation is one of the major conservation issues for biodiversity in Australia. Recently, many new Phytophthora species have been described from Australia's native ecosystems; however, their distribution, origin, and potential impact remain unknown. Historical bias in Phytophthora detection has been towards sites showing symptoms of disease, and traditional isolation methods show variable effectiveness of detecting different Phytophthora species. However, we now have at our disposal new techniques based on the sampling of environmental DNA and metabarcoding through the use of highthroughput sequencing. Here, we report on the diversity and distribution of Phytophthora in Australia using metabarcoding of 640 soil samples and we compare the diversity detected using this technique with that available in curated databases. Phytophthora was detected in 65% of sites, and phylogenetic analysis revealed 68 distinct Phytophthora phylotypes. Of these, 21 were identified as potentially unique taxa and 25 were new detections in natural areas and/or new introductions to Australia. There are 66 Phytophthora taxa listed in Australian databases, 43 of which were also detected in this metabarcoding study. This study revealed high Phytophthora richness within native vegetation and the additional records provide a valuable baseline resource for future studies. Many of the Phytophthora species now uncovered in Australia's native ecosystems are newly described and until more is known we need to be cautious with regard to the spread and conservation management of these new species in Australia's unique ecosystems.

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Section: Introductionmentioning

confidence: 99%

Distribution and diversity of Phytophthora across Australia

Burgess

White

McDougall

et al. 2017

Pac. Conserv. Biol.

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“…are amongst the most serious and invasive plant pathogens on both agricultural and forestry crops (Fry and Goodwin 1997;Rizzo et al 2002). In terms of forestry, the recent emergence of species such as Phytophthora ramorum and P. austrocedrae (Rizzo et al 2002;Greslebin et al 2007) has reinforced the fact that these pathogens are a serious threat to forestry worldwide, both in natural ecosystems and plantations Garbelotto et al 2003;Greslebin and Hansen 2010). The appearance of a needle blight of Pinus spp.…”

Section: Introductionmentioning

confidence: 99%

Pathogenicity and sporulation of Phytophthora pinifolia on Pinus radiata in Chile

Ahumada

Rotella

Slippers

et al. 2013

Australasian Plant Pathol.

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Phytophthora pinifolia causes the needle and shoot disease of Pinus radiata known as Daño Foliar del Pino (DFP) in Chile. The first pathogenicity trials with this organism utilized mycelial plugs placed on stem wounds. These resulted in lesions in the tissue, but did not reproduce the resinous bands on the needles, which are the most characteristics symptoms of the disease under natural conditions. In this study, stem inoculations were repeated, but to complete Koch's postulates fully, and to confirm that P. pinifolia causes the symptoms observed on naturally infected trees, zoospore/sporangial suspensions were used to inoculate pine foliage. This method produced the same symptoms observed on needles infected naturally. These results confirm that P. pinifolia is the causal agent of the Daño Foliar del Pino on P. radiata in Chile and successfully completed Koch's postulates for the first time. Pathogenicity tests on different Pinus spp. and hybrids showed a wide range of responses to inoculation with P. pinifolia mycelial plugs, from highly susceptible to resistant. Monitoring of sporulation revealed that the sporangia commonly remain on the needles for extended periods of time and their frequency of occurrence and dispersal appear to increase during the rainy season.

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“…Resulting colonies were very slow growing (<0.5 mm per day at 17°C) forming dense, white mycelia with coralloid hyphae on V8 agar. Based on colony morphology and sequencing of the ITS region, the isolate was identified as Phytophthora austrocedri, associated with widespread mortality of Austrocedrus chilensis in Patagonia (Greslebin et al, 2007;Greslebin & Hansen, 2010) and Juniperus communis in northern Britain (Green et al, 2012;Green et al, 2015). The ITS sequence of the isolate was deposited in Genbank (Accession no.…”

Section: Figurementioning

confidence: 99%

First report of Phytophthora austrocedri infecting Nootka cypress in Britain

Green

MacAskill

Dun

et al. 2016

New Disease Reports

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Figure 1Figure 2 In early 2011, reports were received of foliage bronzing of Nootka cypress (Callitropsis nootkatensis) at a single location in the Glasgow area of Scotland. The affected tree, a mature specimen planted in a public park, had entirely bronzed foliage ( Fig. 1) and an orange-brown coloured lesion in the phloem around the stem collar. Phloem samples from the lesion margins were plated onto a Phytophthora-selective medium (SMA + MRP; Brasier et al., 2005) and incubated in the dark at room temperature (15-24°C). Resulting colonies were very slow growing (<0.5 mm per day at 17°C) forming dense, white mycelia with coralloid hyphae on V8 agar. Based on colony morphology and sequencing of the ITS region, the isolate was identified as Phytophthora austrocedri, associated with widespread mortality of Austrocedrus chilensis in Patagonia (Greslebin et al., 2007;Greslebin & Hansen, 2010) and Juniperus communis in northern Britain (Green et al., 2012;Green et al., 2015). The ITS sequence of the isolate was deposited in Genbank (Accession no. JQ346530).Excised shoots (approximately 30 cm long) of Nootka cypress were inoculated at their midpoint with mycelial plugs taken from the margins of three-week-old cultures of a single P. austrocedri isolate growing on V8 agar. The inoculation site was wrapped in damp sterile cotton wool secured in place with plastic paraffin film and aluminium foil. The ends of each shoot were also wrapped in damp sterile cotton wool and sealed with plastic paraffin film. Twenty shoots were inoculated with P. austrocedri and 20 shoots inoculated with sterile V8 agar as controls. The shoots were placed in sealed plastic bags containing a damp cotton wall ball and incubated at 16°C in the dark. Eight weeks after inoculation, orange-brown phloem lesions ranging from 12-90 mm in length (mean 52 mm ± 5 [SE]) had developed that extended to either side of the inoculation point (Fig. 2a). Phytophthora austrocedri was re-isolated from the lesion margins. Control shoots remained healthy (Fig. 2b).This is the first finding of P. austrocedri infecting Nootka cypress. Two more declining Nootka cypress trees located in the same park have since been confirmed as infected with P. austrocedri. The pathogen is a statutory listed organism and the outbreak has been contained by destruction of affected trees.

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Phytophthora austrocedrae sp. nov., a new species associated with Austrocedrus chilensis mortality in Patagonia (Argentina)

Cited by 89 publications

References 9 publications

Distribution and diversity of Phytophthora across Australia

Distribution and diversity of Phytophthora across Australia

Pathogenicity and sporulation of Phytophthora pinifolia on Pinus radiata in Chile

First report of Phytophthora austrocedri infecting Nootka cypress in Britain

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