Academic literature on the topic 'Pycnisia'

The biogeographic and phylogenetic relationships of six of the eight Australian genera of freshwater shrimp from the family Atyidae were investigated using mitochondrial 16S rDNA and cytochrome oxidase I sequences. Previous studies on two of the epigean genera (Caridina, Paratya) indicate that Australian species have strong links to congenerics from outside, with Australian members of Paratya being monophyletic and Caridina polyphyletic. The present study found that the endemic Australian epigean genus Australatya forms a strong clade with Pacific ‘Atya-like’ genera (Atyoida, Atyopsis), and that the endemic Australian epigean genus Caridinides falls within a clade containing Caridina species from the Australian ‘indistincta’ group. The two hypogean genera included in this study (Parisia, Pycnisia) form a strong clade in all analyses, implying an Australian subterranean speciation. The possibility of a relationship between Parisia/Pycnisia and an Australian Caridina species may have implications for the monophyly of the highly disjunct genus Parisia (Australia, Madagascar, Philippines). Parisia may descend from local Caridina species and represent convergent morphologies.

Pycnisia raptor, gen. et sp. nov., a new predatory troglobic atyid shrimp from a limestone cave near Katherine, Northern Territory, Australia, is described and illustrated. The shrimp is immediately distinguishable from all other atyids by the presence of robust, raptorial ambulatory pereiopods. The troglobic atyid fauna of Australia is reviewed and a key provided for the identification of the six species of four genera presently known.

A new sooty mould, Chaetocapnodium zapotae, was isolated from Manilkara zapota in central Veracruz, Mexico. An analysis of ITS+LSU nuclear rDNA concatenated sequences of our isolate revealed taxonomic identity at the genus level located in the same clade as Chaetocapnodium insulare and Chaetocapnodium placitae. Morphological examination confirmed that the new species differs from C. insulare in the absence of the sexual morph and the absence of setae on the pycnidia. Additional characters distinguishing C. zapotae from C. placitae are its narrower pycnidial size range, wider size ranges for the hyphae and conidia, and the dark brown color of its pycnidia.

Structural and developmental analysis of Leptoxyphium sp. conidiomata shows that these consist of aggregated hyphae that develop a conidiogenous cavity near the apex. They have both pycnidial and synnematal characters. This lack of specific differences between synnemata and pycnidia emphasizes the artificial character of the previously established distinction between Coelomycètes and Hyphomycetes.

Pycnidial and conidial production by isolates of the four main Neofusicoccum species associated with blueberry in New Zealand was investigated. Pycnidia developed after 8 days on mycelial-inoculated detached green shoots. Conidial ooze was observed after further incubation for 12 h under high relative humidity at 25˚C. Numbers of oozing pycnidia and conidial numbers were generally low, but were significantly affected by isolate and species. Neofusicoccum ribis and N. parvum produced slightly more pycnidia and conidia compared with N. luteum and N. australe. Inoculation of non-wounded and wounded attached green shoots with either N. ribis or N. australe conidia showed that, 14 days after inoculation, lesions developed in wounded shoots only, with N. ribis (58.8 mm) producing longer lesions than N. australe (29.8 mm). Neofusicoccum ribis and N. australe were re-isolated beyond the lesion, with pathogen progression being significantly greater for wounded (47.1 mm) compared with non-wounded shoots (30.4 mm).

On Czapek agar medium, the optimum temperature for spore germination and pycnidia formation by Ampelomyces quisqualis was 20 and 25 °C, respectively. Inoculation of Czapek agar medium with a spore concentration of 106 or 107/mL significantly increased pycnidia formation as compared with medium inoculated with 104 or 105 spores/mL. In shaken cultures, spore formation in potato dextrose broth (PDB) was higher than in the broth of bran extract and glycerol, aspargine, Czapek, Joham, and synthetic Mucor media. On PDB, pycnidia were formed in hard black aggregates. Spore production in fermentors was similar to that in shaken cultures. The omission of glucose from PDB caused a great increase in the number of spores formed. Also, PDB prepared with the broth of 100 g (instead of the usual 200 g) peeled potatoes/L was effective in spore formation and maintained spore infectivity as high as in controls. It seems that the broth of boiled potatoes is a simple, efficient, and nonexpensive medium for mass production of infective A. quisqualis spores. Key words: Ampelomyces quisqualis, pycnidial production, spore formation, biological control, powdery mildew.

Septoria oenotheraeWest. can cause severe damage in overwintered crops of evening primrose (Oenothera spp.), including complete crop loss. Damage would be reduced if the sources of infection could be identified and removed. Examination of seed capsules inoculated with S. oenotheraeshowed that 96% of the pycnidia present were on the outside of the capsules, and seeds bearing pycnidia were only rarely found. However, internal infection of seeds from these capsules was demonstrated by both a blotter test and by culturing on agar media. Immersing seeds in 45°C water for 25 minutes destroyed viable fungal propagules located internally in seeds without reducing seed germination. The pathogen was also shown to overwinter in the pycnidial stage on stems left standing in the field. It is concluded that both internal seed-borne infection and overwintered crop debris are potential sources of infection in commercial seed stocks of evening primrose.

AbstractPrevious studies have identified a close relationship between the monospecific Masonhalea richardsonii and Tuckermannopsis inermis. However, formal taxonomic changes were postponed until existing sequence data could be confirmed. Here we validate these data and discuss the transfer of T. inermis to Masonhalea (made by Lumbsch et al. in Thell & Moberg 2011), consider the morphological, anatomical and biogeographic similarities and differences between these two taxa. The two Masonhalea species both produce lateral apothecia, marginal pycnidia, a layer of cortical tissue beneath the pycnidial wall and bacillariform conidia.

Various species of endophytic fungi produce a variety of potentially useful new Pharmaceuticals in host tissue of different plants. As an example, the anti-cancer drug, taxol is produced by several species of fungi isolated from various host species.A Phoma was isolated from the inner bark of Cephalotaxus fortunei growing near Hangzhou, China. After 7-10 days of incubation at 23C cultures were hyphal tipped and transferred to PDA and gamma-irradiated carnation leaves. Cultures which produced bioactive substances were studied further. This Phoma sp. is particularly active against Pythium ultimum. Another endophytic Phoma sp. isolated from Taxus wallachiana also makes antimetabolite compounds. Presumably these endophytic Phoma spp. exist in a symbiotic relationship with various tree species contributing substances that inhibit or destroy invading pathogenic fungi and bacteria.The fungus produces globose dark brown, thin-walled pycnidia which are semi-immersed in carnation leaf pieces (Fig. 1). Cream-colored conidia (Fig. 2), which average 4.5-5 × 1.75-3 μm are produced in pycnidia with a single ostiole normally obscured by a gelatinous mass (Fig. 3), which is characteristically not evident on old pycnidia (Fig. 4). Conidia are formed enteroblastically from discrete phialidic conidiogonous cells attached directly to the pycnidial wall. Sclerotia (ca. 1.5-2 mm) are also produced on PDA.

Abstract In this study, the fruit bodies (pycnidial) colonization and spore presence of Sphaeropsis sapinea (Fr.) Dyko & B. Sutton on Scots pine (Pinus sylvestris L.) trees in stands affected by long-term drought in the Czech Republic were evaluated. A total of 520 cones at four sites were evaluated every 1.5 months from June 2019 to December 2020. The pycnidia of S. sapinea in relation to colonization by subcortical insects in inner bark and wood, and wood-decaying fungi a total of 340 trunks at 17 sites during the autumn of 2020 were also evaluated. Pycnidial colonization of S. sapinea on cones was significantly higher at the site with the highest air humidity and significantly lower in the sampling periods of June 2019, August 2019, and November 2019, which were characterized by low precipitation levels. S. sapinea spore presence on cones was significantly higher at sites in Bohemia compared to those in Moravia, in sites with higher air humidity, and in three consecutive sampling periods in March 2020–June 2020. Pycnidial colonization of S. sapinea on trunks was significantly positively dependent on the colonization of subcortical insects in both inner bark and wood, but not with the colonization of wood-decaying fungi. The results of this study show a positive relationship between high humidity and colonization by subcortical insects in inner bark and wood with S. sapinea on Scots pine.

The aim of this thesis is to use phylogenetic analyses of mitochondrial DNA to investigate the biogeography and evolutionary relationships within the freshwater shrimp family Atyidae in Australia at a nested series of scales, both geographic and systematic. At the largest scale, the relationships between Australian and Indo-West Pacific species were inferred using the two most common atyid genera in Australia, Caridina and Paratya. Most atyids are hypothesised to have colonised Australia from Southeast Asia, but Paratya may be a Gondwanan relict given its distribution. Australian Paratya all form a strong clade, with a sister relationship to species from Tasman Sea islands. Molecular clock estimates place all of the splits within Paratya after the break-up of Gondwana, with Australia being colonised once 3½-8½ million years ago. This transoceanic dispersal is conjectured to have taken place through oceanic currents because of the amphidromous life cycle of some taxa of Paratya. Caridina has a very different biogeographic history in Australia, as numerous Australian species have close evolutionary relationships with non-Australian taxa from locations throughout the region. This implies many colonisations to or from Australia over a long period, and thus highlights the surprising adeptness of freshwater shrimp in dispersal across ocean barriers and the unity of much of the region's freshwater biota. A number of potential species radiations within Australia were also identified. This agrees with patterns detected for a large number of Australian freshwater taxa, and implies a vicariant explanation due to the development of colder, dryer climates. The systematic relationships of the remaining two Australian surface genera (Caridinides, Australatya) and two subterranean genera (Parisia, Pycnisia) were also investigated. Australatya forms a strong clade with Pacific 'Atya-like' genera, and Caridinides falls within a clade containing Australian Caridina. The hypogean genera, Parisia and Pycnisia, form a strong clade in all analyses, implying an Australian subterranean speciation. The possibility of a relationship between Parisia/Pycnisia and some Australian Caridina species may have implications for the monophyly of the highly disjunct genus Parisia, as it may descend from local Caridina species and represent convergent morphologies. The common and speciose genus Caridina was used as a model taxon for analyses within Australia. At the medium scale, molecular taxonomic techniques were used to uncover cryptic species within a problematic east Australian species complex. At least five species were detected. Phylogeographic and population genetic analyses were carried out on each of these five cryptic species, which diverged from each other in the late Miocene/Pliocene. There were very large differences between the species in the scales of overall geographic distribution, intraspecific divergence and population structure. These were characterised as either: 1) species with large ranges, low intraspecific divergence, limited phylogeographic structuring (Caridina sp. D); 2) species with large ranges, high intraspecific divergence, a high level of phylogeographic structuring (sp. B); 3) species with a limited range, low intraspecific divergence, no phylogeographic structuring (sp. E); or 4) species with limited ranges, high intraspecific divergences, a high level of phylogeographic structuring (sp. A & C). These patterns reflect a combination of large-scale factors, such as landscape structure and climate change, and small-scale factors, such as species-specific tolerances to local conditions and differing dispersal capabilities. Life history variation (egg size) between species may be correlated with different dispersal abilities. Species with the smallest eggs have the least intraspecific divergence and largest distribution, while those with the biggest eggs have the most divergence and smallest distribution, with medium-sized egg species in between. At the smallest phylogeographic scale, C. sp. C from the sand dune islands of Moreton Bay in southeastern Queensland was further analysed. Two different lineages (C1, C2) were found which diverged from each other during the late Miocene/Pliocene and so are older than the current landscape in which they are found. Small-scale phylogeographic analyses within C1, C2 and a sympatric fish identified divergences dating to the Pleistocene (about 100-300 thousand years ago). This implies that ice age sea-level changes may have structured these populations, although there is little observable influence of the last glacial maximum (about 18 thousand years ago). This study has highlighted a number of taxonomic anomalies within the Atyidae. The detection of many cryptic species implies that biodiversity within freshwater invertebrates is higher than currently appreciated. The evolutionary and biogeographic relationships of Australian atyids have proved complex, with many taxa having their own individual histories. At the large Indo-Pacific scale, dispersal is most evident, but within Australia, both vicariance and dispersal have been responsible for structuring all taxa at every scale.

The aim of this thesis is to use phylogenetic analyses of mitochondrial DNA to investigate the biogeography and evolutionary relationships within the freshwater shrimp family Atyidae in Australia at a nested series of scales, both geographic and systematic. At the largest scale, the relationships between Australian and Indo-West Pacific species were inferred using the two most common atyid genera in Australia, Caridina and Paratya. Most atyids are hypothesised to have colonised Australia from Southeast Asia, but Paratya may be a Gondwanan relict given its distribution. Australian Paratya all form a strong clade, with a sister relationship to species from Tasman Sea islands. Molecular clock estimates place all of the splits within Paratya after the break-up of Gondwana, with Australia being colonised once 3½-8½ million years ago. This transoceanic dispersal is conjectured to have taken place through oceanic currents because of the amphidromous life cycle of some taxa of Paratya. Caridina has a very different biogeographic history in Australia, as numerous Australian species have close evolutionary relationships with non-Australian taxa from locations throughout the region. This implies many colonisations to or from Australia over a long period, and thus highlights the surprising adeptness of freshwater shrimp in dispersal across ocean barriers and the unity of much of the region's freshwater biota. A number of potential species radiations within Australia were also identified. This agrees with patterns detected for a large number of Australian freshwater taxa, and implies a vicariant explanation due to the development of colder, dryer climates. The systematic relationships of the remaining two Australian surface genera (Caridinides, Australatya) and two subterranean genera (Parisia, Pycnisia) were also investigated. Australatya forms a strong clade with Pacific 'Atya-like' genera, and Caridinides falls within a clade containing Australian Caridina. The hypogean genera, Parisia and Pycnisia, form a strong clade in all analyses, implying an Australian subterranean speciation. The possibility of a relationship between Parisia/Pycnisia and some Australian Caridina species may have implications for the monophyly of the highly disjunct genus Parisia, as it may descend from local Caridina species and represent convergent morphologies. The common and speciose genus Caridina was used as a model taxon for analyses within Australia. At the medium scale, molecular taxonomic techniques were used to uncover cryptic species within a problematic east Australian species complex. At least five species were detected. Phylogeographic and population genetic analyses were carried out on each of these five cryptic species, which diverged from each other in the late Miocene/Pliocene. There were very large differences between the species in the scales of overall geographic distribution, intraspecific divergence and population structure. These were characterised as either: 1) species with large ranges, low intraspecific divergence, limited phylogeographic structuring (Caridina sp. D); 2) species with large ranges, high intraspecific divergence, a high level of phylogeographic structuring (sp. B); 3) species with a limited range, low intraspecific divergence, no phylogeographic structuring (sp. E); or 4) species with limited ranges, high intraspecific divergences, a high level of phylogeographic structuring (sp. A & C). These patterns reflect a combination of large-scale factors, such as landscape structure and climate change, and small-scale factors, such as species-specific tolerances to local conditions and differing dispersal capabilities. Life history variation (egg size) between species may be correlated with different dispersal abilities. Species with the smallest eggs have the least intraspecific divergence and largest distribution, while those with the biggest eggs have the most divergence and smallest distribution, with medium-sized egg species in between. At the smallest phylogeographic scale, C. sp. C from the sand dune islands of Moreton Bay in southeastern Queensland was further analysed. Two different lineages (C1, C2) were found which diverged from each other during the late Miocene/Pliocene and so are older than the current landscape in which they are found. Small-scale phylogeographic analyses within C1, C2 and a sympatric fish identified divergences dating to the Pleistocene (about 100-300 thousand years ago). This implies that ice age sea-level changes may have structured these populations, although there is little observable influence of the last glacial maximum (about 18 thousand years ago). This study has highlighted a number of taxonomic anomalies within the Atyidae. The detection of many cryptic species implies that biodiversity within freshwater invertebrates is higher than currently appreciated. The evolutionary and biogeographic relationships of Australian atyids have proved complex, with many taxa having their own individual histories. At the large Indo-Pacific scale, dispersal is most evident, but within Australia, both vicariance and dispersal have been responsible for structuring all taxa at every scale.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
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L’ascomicete Guignardia bidwellii, agente causale del marciume nero della vite, è un patogeno economicamente importante in alcuni areali viticoli. La conoscenza, disponibile sul marciume nero dell’uva, è stata recuperata dalla letteratura, analizzata e sintetizzata per sviluppare un modello meccanicistico del ciclo di vita del patogeno, guidata dalle variabili meteorologiche e dalla fenologia della vite, e basata sull'analisi dei sistemi. Il modello è stato poi valutato per la sua capacità di rappresentare il sistema reale e la sua utilità per la comprensione di epidemie di marciume nero su foglie e grappoli in un vigneto del Nord Italia, nel 2013 al 2015. Successivamente, le mancanze di conoscenza sono state analizzate, studiate e quindi colmate attraverso specifici esperimenti. In un primo passo, le dinamiche dell’inoculo primario e dei modelli di dispersione (di entrambi ascospore e conidi) da mummie svernate sono state studiate in un vigneto sperimentale per tre anni. In un secondo passo, l'effetto della temperatura e dell'umidità sulla formazione di picnidi di G. bidwellii e la successiva estrusione di cirri, nelle lesioni su foglia, la produzione e la germinazione dei conidi (inoculo secondario), e la lunghezza del periodo di latenza sono stati studiati sia in condizioni di campo che in ambiente controllato. In un terzo passo, sono stati condotti studi in ambiente controllato per studiare la produzione di conidi di G. bidwellii sulle lesioni di foglie, influenzata da lavaggi ripetuti e alternando periodi di secco ed umido. Il modello epidemiologico sviluppato in questa tesi può essere utilizzata da viticoltori come strumento predittivo per la pianificazione di trattamenti fungicidi nei vigneti.
The ascomycete Guignardia bidwellii, causal agent of black-rot on grapevines, is an economically important pathogen in some viticultural areas. The available knowledge on black-rot of grape was retrieved from literature, analyzed, and synthesized to develop a mechanistic model of the life cycle of the pathogen, driven by weather and vine phenology, and based on the systems analysis. The model was then evaluated for its ability to represent the real system and its usefulness for understanding black-rot epidemics on leaves and bunches in a vineyard of north Italy, in 2013 to 2015. Thereafter, weaknesses in our knowledge were analysed and studied through specific experiments. In a first step, dynamics of primary inoculum and dispersal patterns (both ascospores and conidia) from overwintered grape mummies were investigated in an experimental vineyard during three years. In a second step, the effect of temperature and humidity on the formation of G. bidwellii pycnidia and the extrusion of cirri in grape leaf lesions, production and germination of conidia (secondary inoculum), and the length of the latency period were studied under both environmental and controlled conditions. In a third step, environmental-controlled studies were conducted to investigate the production course of G. bidwellii conidia on grape leaf lesions as influenced by repeated washing events and alternate dry and wet periods. The model developed in this thesis can be used by vinegrowers as a predictive tool for scheduling fungicide sprays in the vineyards.