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 Identification of a New Phytophthora Species Causing Root and Runner Rot of Cranberry in New Jersey

2005 ◽  
Vol 95 (10) ◽  
pp. 1237-1243 ◽  
Author(s):  
James J. Polashock ◽  
Jennifer Vaiciunas ◽  
Peter V. Oudemans
Keyword(s):  
New Jersey ◽  
Phytophthora Cinnamomi ◽  
Phosphorous Acid ◽  
Distinct Species ◽  
Phytophthora Species ◽  
Growth Effect ◽  
5.8S Rdna ◽  
Pathogenicity Tests ◽  
Temperature Preferences ◽  
Cardinal Temperatures

In New Jersey, Phytophthora cinnamomi is the pathogen most commonly isolated from diseased roots and runners of the cultivated cranberry (Vaccinium macrocarpon). A second distinct species of Phytophthora has been isolated from dying cranberry plants and surface irrigation water. This species is homothallic with paragynous antheridia and ellipsoid-limoniform, nonpapillate sporangia. It was tentatively identified as P. megasperma in an earlier report. Laboratory experiments demonstrate that the cardinal temperatures for vegetative growth are between 5 and 30°C with an optimum near 25°C. Sporangia are produced at temperatures between 10 and 20°C with the majority of sporangia produced at 10 and 15°C. In pathogenicity tests, no growth effect was observed on cranberry plants (cv. Early Black) when tests were conducted at 25°C; however, significant reductions in plant growth occurred when tests were conducted at 15°C. This species was insensitive to metalaxyl but was sensitive to buffered phosphorous acid. Sequence analysis of the internal transcribed spacer 1 (ITS1), 5.8S rDNA, and ITS2 regions place these isolates in Phytophthora clade 6 with greatest similarity to Phytophthora taxon raspberry. To our knowledge, this is the first report of isolates of this affiliation in North America. However, the observation of low temperature preferences makes this species unique in an otherwise high temperature clade. The isolates described in this study are tentatively classified as Phytophthora taxon cranberry.

Comparative Behaviour of Phytophthora Species in the Secondary Phloem of Stems and Excised Roots of Banksia grandis and Eucalyptus marginata

1987 ◽  
Vol 35 (1) ◽  
pp. 103 ◽  
Author(s):  
BL Shearer ◽  
BJ Michaelsen ◽  
HJ Warren
Keyword(s):  
Response Curve ◽  
Growth Response ◽  
Phytophthora Cinnamomi ◽  
Similar Rate ◽  
Phytophthora Species ◽  
Phytophthora Cactorum ◽  
Secondary Phloem ◽  
Eucalyptus Marginata ◽  
Temperature Growth ◽  
Rates Of Growth

We inoculated excised roots under controlled laboratory conditions and inoculated stems in the field to compare the behaviour of Phytophthora cactorum, P. cambivora, P. cinnamomi A2, P. citricola, P. cryptogea A1 and A2, P. megasperma var. sojae and P. nicotianae var. parasitica in the secondary phloem of Banksia grandis and Eucalyptus marginata. Most of the Phytophthora species grew in excised roots of E. marginata at a similar rate. Of the Phytophthora species with similar rates of growth in E. marginata roots, P. cinnamomi was the only species that consistently grew faster in excised roots of B. grandis than in roots of E. marginata. The growth of the Phytophthora species in excised roots under controlled conditions was significantly correlated with growth in intact stems in the field. Over a range of temperatures between 10 and 25°C, the slope of the temperature-growth response curve for P. cinnamomi in excised roots of B. grandis was greater than that for P. citricola. At temperatures between 27 and 31°C, growth rates of P. cinnarnomi in excised roots of B. grandis were 1 cm or more per day compared with 0.3 cm per day for P. citricola. Differences in growth rate in the roots of the widespread understorey species B. grandis can be important to the epidemiology of a Phytophthora species in the E. marginata forest. Phytophthora cinnamomi with fast rates of growth in roots of B. grandis is more likely to have inoculum in the vicinity of major roots of E. marginata than are Phytophthora species with slow rates of growth.

Comparative Morphology and Behaviour of A1 and A2 Isolates of Phytophthora cinnamomi

1974 ◽  
Vol 22 (3) ◽  
pp. 461 ◽  
Author(s):  
CJ Shepherd ◽  
BH Pratt ◽  
PA Taylor
Keyword(s):  
Growth Rate ◽  
Plant Communities ◽  
Phytophthora Cinnamomi ◽  
Comparative Morphology ◽  
Native Plant ◽  
Temperature Growth ◽  
General Similarity ◽  
Similar Temperature ◽  
The Mean ◽  
Osmotic Potentials

Studies of morphology, physiological behaviour and pathogenicity indicated that some significant differences existed between isolates of the A1 and A2 compatibility types of Phytophthora cinnamomi from native plant communities in Australia. The majority of A1 isolates produced zoosporangia more rapidly and in greater numbers than A2 isolates, and zoosporangia were produced evenly on mycelial discs of A1 isolates whereas they occurred mostly at the perimeter of similar discs in the case of A2 isolates. Chlamydospores were produced more rapidly by A1 than A2 isolates, and in the former tended to be of an even size and were frequently single, whereas in A2 isolates the size was extremely variable and production was usually in clusters. Both compatibility types showed similar temperature-growth optima, but the mean growth rate of A1 isolates, over the range 15-30°C, was less than that of A2 isolates. Both types responded similarly to high temperature treatments and to a range of osmotic potentials and both showed similar pathogenicity to lupin and Pinus radiata seedlings. While both compatibility types showed similar reactions to a number of inhibitors, the growth of A2 isolates was inhibited more by rose bengal and pyronin G than that of A1 isolates. Thus, although significant differences were recorded, there was a general similarity of behaviour of isolates of both compatibility types and there were no striking differences from the recorded behaviour of the fungus in other countries.

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.

High temperature growth rate in MOCVD growth of AlGaAs

1984 ◽  
Vol 68 (1) ◽  
pp. 169-175 ◽  
Author(s):  
Tetsuo Soga ◽  
Yasuhito Takahashi ◽  
Shiro Sakai ◽  
Masayoshi Umeno
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Temperature Growth ◽  
Mocvd Growth

Detection of oomycide-insensitive Phytophthora isolates in Maryland ornamental nurseries and Mid-Atlantic landscapes provide data for reconsidering management strategies

2021 ◽  
Author(s):  
Justine Beaulieu ◽  
Johanna Del Castillo Munera ◽  
Yilmaz Balci
Keyword(s):  
Growth Rate ◽  
Mycelial Growth ◽  
Management Strategies ◽  
Resistance Management ◽  
Phytophthora Species ◽  
Oak Forests ◽  
Relative Growth ◽  
Off Label ◽  
Potting Media ◽  
Almost All

Five Phytophthora species comprising a total of 243 isolates (77 P. cinnamomi, 23 P. citrophthora, 18 P. multivora, 18 P. pini, and 107 P. plurivora) were screened for sensitivity to mefenoxam, fosetyl-Al, dimethomorph, dimethomorph + ametoctradin and fluoxastrobin using amended agar assays. Mefenoxam-insensitive isolates were detected within P. cinnamomi (4%), P. multivora (11%), and P. plurivora (12%) even at approximately 2.5x the recommended label rate. These isolates were also insensitive to higher (off-label) concentrations of fluoxastrobin. Concentrations of dimethomorph (400 g/mL) and dimethomorph + ametoctradin (100 g/mL) were mostly effective in mycelial growth inhibition, but two P. plurivora isolates were insensitive, suggesting that resistance management is required. All mefenoxam-insensitive isolates were sensitive to fosetyl-Al at the label rate. Surprisingly, the populations of P. cinnamomi from mid-Atlantic oak forests included insensitive isolates. With almost all species, isolates recovered from asymptomatic hosts (e.g., soil/potting media collected of randomly selected asymptomatic hosts) had a significantly greater relative growth rate when compared to isolates recovered from symptomatic hosts (e.g., isolates recovered from lesions or wilted plants). These findings suggest that mefenoxam should no longer be used to manage oomycetes in Maryland ornamental nurseries and that the use of fluoxastrobin should be limited.

Evaluation of temperature effect on growth rate of Lactobacillus rhamnosus GG in milk using secondary models

2013 ◽  
Vol 67 (7) ◽  
Author(s):  
Ľubomír Valík ◽  
Alžbeta Medveďová ◽  
Michal Čižniar ◽  
Denisa Liptáková
Keyword(s):  
Growth Rate ◽  
Growth Parameters ◽  
Lactobacillus Rhamnosus ◽  
Probiotic Bacterium ◽  
Extended Model ◽  
Temperature Model ◽  
Lactobacillus Rhamnosus Gg ◽  
Model Application ◽  
Cardinal Temperature ◽  
Cardinal Temperatures

AbstractThe application of secondary temperature models on growth rates of Lactobacillus rhamnosus GG, the much studied probiotic bacterium, is investigated. Growth parameters resulting from a primary fitting were modelled against temperature using the following models: Hinshelwood model (H), Ratkowsky extended model (RTK2), Zwietering model (ZWT), and cardinal temperature model with inflection (CTMI). As experienced by other authors, the RTK2, ZWT, and CTMI models provided the best statistical indices related to fitting the experimental data. Moreover, with the biological background, the following cardinal temperatures of L. rhamnosus GG resulted from the study by the model application: t min = 2.7°C, t opt = 44.4°C, t max = 52.0°C. The growth rate of the strain under study at optimal temperature was 0.88 log10(CFU mL−1 h−1).

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.

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