Mating Behaviour of Australian Isolates of Phytophthora Species. II. Phytophthora cinnamomi

1978 ◽  
Vol 26 (2) ◽  
pp. 139 ◽  
Author(s):  
CJ Shepherd ◽  
RB Cunningham
Keyword(s):  
Statistical Analysis ◽  
Western Australia ◽  
Culture Medium ◽  
Phytophthora Cinnamomi ◽  
Mating Behaviour ◽  
Phytophthora Species ◽  
Taxonomic Significance ◽  
South Eastern

Determinations were made of the patterns of oogonial occurrence in the culture medium, the numbers of oogonia produced and of aborted oogonia formed in matings between 18 A1 and 116 A2 compatability type isolates of Phytophthora cinnamomi from south-eastern and Western Australia. The majority of the A2 isolates mated freely with their A1 counterparts, but three A2 isolates mated with only some of the A1 testers and five others were sterile. Patterns of occurrence of oogonia, their quantitative production and the percentage of aborted oogonia produced were affected by the particular isolates used. Statistical analysis of the data showed that the nine populations of A2 isolates were significantly different from each other in all three parameters studied. Populations from Eden and Bemm River were markedly less fertile than those from other regions. These findings are consistent with the hypothesis that P. cinnamomi is an allochthonous organism in Australia. Oogonial size was found to vary according to position within the mating plate and according to the particular isolates used, although different geographical groups of isolates could not be dis- tinguished. Abnormally small oogonia were produced in matings involving three of the A2 isolates. The taxonomic significance of these findings is discussed.

The Distribution of Phytophthora cinnamomi Rands at Two Sites in Southern Western Australia and at Durras in South-Eastern New South Wales.

1982 ◽  
Vol 30 (2) ◽  
pp. 139 ◽  
Author(s):  
WM Blowes ◽  
WA Heather ◽  
N Malajczuk ◽  
SR Shea
Keyword(s):  
Western Australia ◽  
Phytophthora Cinnamomi ◽  
New South ◽  
New South Wales ◽  
Native Forest ◽  
Prevention Strategies ◽  
South Eastern ◽  
Isolation Techniques ◽  
South Wales ◽  
Western Australian

Native forest at Durras in south-eastern New South Wales and Jarrahdale in south-western Western Australia was examined for the presence of Phytophthora cinnamomi by two sampling and isolation techniques. With the lupin seeding baiting technique, randomly selected samples of soil and fine roots collected from the New South Wales site yielded P. cinnamomi when baited, while similar baiting of comparable samples from Western Australia failed. Direct plating of samples of upper roots and root collars of recently dead Banksia grandis from Western Australian sites yielded P. cinnamomi, while this organism was not isolated from comparable samples of chlorotic Macrozamia communis collected at the New South Wales site. The results suggest that the form of occurrence of P. cinnamomi and its association with disease in Australia vary in different situations. Viewing each situation independently might ensure the adoption of control/prevention strategies appropriate to all.

scholarly journals Re-evaluation of Phytophthora Species Isolated During 30 Years of Vegetation Health Surveys in Western Australia Using Molecular Techniques

Plant Disease ◽  
2009 ◽  
Vol 93 (3) ◽  
pp. 215-223 ◽  
Author(s):  
Treena I. Burgess ◽  
Janet L. Webster ◽  
Juanita A. Ciampini ◽  
Diane White ◽  
Giles E. StJ. Hardy ◽  
...  
Keyword(s):  
New Taxa ◽  
Western Australia ◽  
Dna Sequences ◽  
Phytophthora Cinnamomi ◽  
Sequence Data ◽  
Phytophthora Species ◽  
Molecular Techniques ◽  
Similar Species ◽  
Eucalyptus Marginata ◽  
Similar Morphology

For 30 years, large-scale aerial photography has been used to map the extent of Phytophthora dieback disease in native forests in the southwest of Western Australia, with validation of the observations involving routine testing of soil and root samples for the presence of Phytophthora cinnamomi. In addition to P. cinnamomi, six morpho-species have been identified using this technique: P. citricola, P. megasperma, P. cryptogea, P. drechsleri, P. nicotianae, and P. boehmeriae. In recent years, many new Phytophthora species have been described worldwide, often with similar morphology to existing species; thus, as many of the isolates collected in Western Australia have been difficult to identify based on morphology, molecular identification of the morpho-species is required. Based on amplification of the internal transcribed spacer (ITS) region of the rDNA gene, sequence data of more than 230 isolates were compared with those of existing species and undescribed taxa. P. inundata, P. asparagi, P. taxon PgChlamydo, P. taxon personii, and P. taxon niederhauserii were identified based on sequence data. Phylogenetic analysis revealed that nine potentially new and undescribed taxa can be distinguished. Several of the new taxa are morphologically indistinguishable from species such as P. citricola, P. drechsleri, and P. megasperma. In some cases, the new taxa are closely related to species with similar morphology (e.g., P.sp.4 and P. citricola). However, the DNA sequences of other new taxa such as P.sp.3 and P.sp.9 show that they are not closely related to morphologically similar species P. drechsleri and P. megasperma, respectively. Most of the new taxa have been associated with dying Banksia spp., while P.sp.2 and P.sp.4 have also been isolated from dying Eucalyptus marginata (jarrah). Some taxa (P.sp.3, 6, and 7) appear to have limited distribution, while others like P.sp.4 are widespread.

Metabolic stability of Phytophthora cinnamomi Rands in Western Australia

1986 ◽  
Vol 32 (10) ◽  
pp. 820-822
Author(s):  
R. M. Hart ◽  
D. Keast ◽  
G. Smythe
Keyword(s):  
Statistical Analysis ◽  
Western Australia ◽  
Glucose Utilization ◽  
Phytophthora Cinnamomi ◽  
Metabolic Stability ◽  
Biochemical System ◽  
Solid Media ◽  
Before And After ◽  
The Media ◽  
Metabolic Variation

Ten isolates of Phytophthora cinnamomi Rands from Western Australia were tested for metabolic variation using a commercial miniaturized biochemical system developed for bacteriology. The isolates included the two mating strains, and had been maintained in the laboratory for various times. The isolates were tested before and after repeated passaging on solid media. Statistical analysis of the biochemical results showed no major differences between the isolates, and for the most part they appear to be stable in cultivation. However, there were small passage effects on some of the media, particularly with glucose utilization.

scholarly journals Phytophthora mediterranea sp. nov., a New Species Closely Related to Phytophthora cinnamomi from Nursery Plants of Myrtus communis in Italy

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 682
Author(s):  
Carlo Bregant ◽  
Antonio A. Mulas ◽  
Giovanni Rossetto ◽  
Antonio Deidda ◽  
Lucia Maddau ◽  
...  
Keyword(s):  
New Species ◽  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Colony Growth ◽  
Phytophthora Species ◽  
Maximum Temperature ◽  
Pathogenicity Test ◽  
Forest Nurseries ◽  
Collar And Root Rot ◽  
A New Species

Monitoring surveys of Phytophthora related diseases in four forest nurseries in Italy revealed the occurrence of fourteen Phytophthora species to be associated with collar and root rot on fourteen plants typical of Mediterranean and alpine regions. In addition, a multilocus phylogeny analysis based on nuclear ITS and ß-tubulin and mitochondrial cox1 sequences, as well as micromorphological features, supported the description of a new species belonging to the phylogenetic clade 7c, Phytophthora mediterranea sp. nov. Phytophthora mediterranea was shown to be associated with collar and root rot symptoms on myrtle seedlings. Phylogenetically, P. mediterranea is closely related to P. cinnamomi but the two species differ in 87 nucleotides in the three studied DNA regions. Morphologically P. mediterranea can be easily distinguished from P. cinnamomi on the basis of its smaller sporangia, colony growth pattern and higher optimum and maximum temperature values. Data from the pathogenicity test showed that P. mediterranea has the potential to threaten the native Mediterranean maquis vegetation. Finally, the discovery of P. cinnamomi in alpine nurseries, confirms the progressive expansion of this species towards cold environments, probably driven by climate change.

scholarly journals Antifungal Activity of Western Australian Soil Actinomycetes against Phytophthora and Pythium Species and a Mycorrhizal Fungus, Laccaria laccata

1983 ◽  
Vol 36 (2) ◽  
pp. 191 ◽  
Author(s):  
D Keast ◽  
C Tonkin
Keyword(s):  
Antifungal Activity ◽  
Phytophthora Cinnamomi ◽  
Mycorrhizal Fungus ◽  
Organic Matter Content ◽  
Phytophthora Species ◽  
Matter Content ◽  
Soil Organic Matter Content ◽  
Soil Actinomycetes ◽  
High Degree

Soil pH, soil moisture content and soil organic matter content did not appear to influence significantly the total numbers of actinomycetes isolated from sample sites in Western Australia. However, seasonal influences exist with summer conditions leading to higher spore isolation. Substantial but non-specific antifungal activity against Phytophthora cinnamomi, P. cryptogea, P. nicotiana, Pythium proli/erum and L. laccata was detected in vitro from many of the 2367 actinomycetes isolated. Antifungal activity mayor may not occur in members of the same actinomycete group, suggesting segregation of antifungal capacity within all groups. A limited number of actinomycete groups was isolated from the rhizosphere of plants and these exhibited similar properties to their counterparts in soil or litter. Actinomycetes isolated from the rhizosphere of Pinus radiata produced a high degree of in vitro antifungal activity against the Phytophthora species but, in general, actinomycetes isolated from root surfaces exhibited antibiosis against all the fungi tested. More actinomycetes showed antifungal activity from soils where P. cinnamomi was causing dieback of jarrah and other understorey species.

Seasonal fluctuations in river bacteria as measured by multivariate statistical analysis of continuous cultures

1982 ◽  
Vol 28 (8) ◽  
pp. 959-975 ◽  
Author(s):  
Colin R. Bell ◽  
Maxine A. Holder-Franklin ◽  
Mervyn Franklin
Keyword(s):  
Statistical Analysis ◽  
Continuous Culture ◽  
Culture Medium ◽  
Nitrogen Concentration ◽  
Diversity Analysis ◽  
Seasonal Fluctuations ◽  
High Nitrogen ◽  
Continuous Cultures ◽  
Multivariate Statistical ◽  
Nitrogen Concentrations

Forty-eight continuous culture enrichments were performed on summer and winter water samples from two contrasting rivers. The cell output from each chemostat was dependant on the temperature and nitrogen concentration of each enrichment. The diversity of the populations from the continuous cultures, as assessed by species diversity analysis, was always greater than populations obtained on agar plates. However, the species isolated exclusively by continuous culture in these experiments were not unique to the chemostat. All of these species had been isolated at some time on plates directly. High nitrogen concentrations were found to decrease diversity. Populations sampled during the winter were influenced primarily by the concentration of nitrogen. Summer isolates were affected mainly by the temperature of the culture medium. The nutritional versatility of the population was not affected by enrichment of the continuous culture.

Temperature-Growth Relations and Genetic Diversity of A2 Mating-Type Isolates of Phytophthora cinnamomi in Australia

1974 ◽  
Vol 22 (2) ◽  
pp. 231 ◽  
Author(s):  
CJ Shepherd ◽  
BH Pratt
Keyword(s):  
Growth Rate ◽  
First Generation ◽  
Phytophthora Cinnamomi ◽  
Phytophthora Species ◽  
Temperature Growth ◽  
Field Isolates ◽  
Place Of Origin ◽  
Successive Generations ◽  
Cardinal Temperatures ◽  
Range Of Values

Determinations of cardinal temperatures for growth on various media of 50 Australian isolates of Phytophthova cinnamomi showed that growth did not occur outside the range 5-35°C. The range of temperatures at which growth optima occurred varied according to the isolate and medium used and encompassed the whole range of values reported by overseas authors. Growth rates of 361 isolates on corn meal agar at 25°C varied within the range 4.7-10.5 mm/day. There was no correlation between optimum temperature and whether isolates were slow- or fastgrowing or their place of origin. Fast-growing isolates (6-11 mm/day) were obtained from all States, but slower-growing isolates (<6 mm/day) were obtained only from southern and western regions of Australia. Populations from different regions of Australia exhibited different growth rate parameters. The variability of mycelial isolates in culture was studied by examining differences in growth rate among replicated parent, single-zoospore, single-zoosporangium and single terminal-hyphal isolates. Extensive variation was found among first generation single-zoospore progenies of field isolates, with lesser variation among progeny of single zoosporangia, terminal hyphal cultures and second and third generation zoospore derivatives. The origin of this variation is discussed and it is suggested that field isolates are heterokaryotic, since zoospores proved to be predominantly uninucleate. When various Phytophthora species were incubated at temperatures above those at which growth was possible and then returned to 25°C, their subsequent ability to resume growth depended on the particular time-temperature combination used. Considerable variation of response was found among a number of isolates of P. cinnamomi and, following the establishment of single zoospore isolates, the potential variability of field isolates was shown to persist through successive generations of zoospore propagation. It is suggested that a cytoplasmic mechanism of inheritance may be responsible for this variation.

scholarly journals Pathogenicity of four Phytophthora species on kauri in vitro and glasshouse trials

2014 ◽  
Vol 67 ◽  
pp. 54-59 ◽  
Author(s):  
I.J. Horner ◽  
E.G. Hough
Keyword(s):  
Plant Growth ◽  
Forest Soils ◽  
Phytophthora Cinnamomi ◽  
Phytophthora Species ◽  
The Other ◽  
Root Damage ◽  
Soil Inoculation

In kauri forest soils surveys Phytophthora taxon Agathis (PTA) P cinnamomi P multivora and P cryptogea were detected frequently In vitro and glasshouse studies determined that all four Phytophthora species produced lesions on excised kauri leaves and stems Lesion advance was significantly slower with P cinnamomi P multivora and P cryptogea than with PTA When 2yearold kauri seedlings were trunkinoculated lesion spread was rapid with PTA trunks were girdled and all trees died within 46 weeks Phytophthora cinnamomi P multivora and P cryptogea produced substantially smaller lesions than PTA no trees died and plant growth was only slightly suppressed Following soil inoculation with PTA all kauri seedlings died within 10 weeks There were no deaths following soil inoculation with P cinnamomi P multivora or P cryptogea although feeder root damage was observed and the respective pathogens were reisolated Results suggest that PTA is an aggressive pathogen and the other three species are weaker pathogens of kauri

scholarly journals An Overview of Phytophthora Species Inhabiting Declining Quercus suber Stands in Sardinia (Italy)

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 971
Author(s):  
Salvatore Seddaiu ◽  
Andrea Brandano ◽  
Pino Angelo Ruiu ◽  
Clizia Sechi ◽  
Bruno Scanu
Keyword(s):  
Rhizosphere Soil ◽  
Phytophthora Cinnamomi ◽  
Stream Water ◽  
Morphological Characters ◽  
Quercus Suber ◽  
Phytophthora Species ◽  
Cork Oak ◽  
Oak Forests ◽  
Primary Role ◽  
Ecological Value

Cork oak forests are of immense importance in terms of economic, cultural, and ecological value in the Mediterranean regions. Since the beginning of the 20th century, these forests ecosystems have been threatened by several factors, including human intervention, climate change, wildfires, pathogens, and pests. Several studies have demonstrated the primary role of the oomycete Phytophthora cinnamomi Ronds in the widespread decline of cork oaks in Portugal, Spain, southern France, and Italy, although other congeneric species have also been occasionally associated. Between 2015 and 2019, independent surveys were undertaken to determine the diversity of Phytophthora species in declining cork oak stands in Sardinia (Italy). Rhizosphere soil samples were collected from 39 declining cork oak stands and baited in the laboratory with oak leaflets. In addition, the occurrence of Phytophthora was assayed using an in-situ baiting technique in rivers and streams located throughout ten of the surveyed oak stands. Isolates were identified by means of both morphological characters and sequence analysis of internal transcribed spacer (ITS) regions of ribosomal DNA. In total, 14 different Phytophthora species were detected. Phytophthora cinnamomi was the most frequently isolated species from rhizosphere soil, followed by P. quercina, P. pseudocryptogea, and P. tyrrhenica. In contrast, P. gonapodyides turned out to be the most dominant species in stream water, followed by P. bilorbang, P. pseudocryptogea, P. lacustris, and P. plurivora. Pathogenicity of the most common Phytophthora species detected was tested using both soil infestation and log inoculation methods. This study showed the high diversity of Phytophthora species inhabiting soil and watercourses, including several previously unrecorded species potentially involved in the decline of cork oak forests.

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