Letteratura scientifica selezionata sul tema "Phytophthora cinnamomi"
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Articoli di riviste sul tema "Phytophthora cinnamomi"
1
HARDHAM, ADRIENNE R. "Phytophthora cinnamomi". Molecular Plant Pathology 6, n. 6 (novembre 2005): 589–604. http://dx.doi.org/10.1111/j.1364-3703.2005.00308.x.
Testo completo
2
Hardham, Adrienne R., e Leila M. Blackman. "Phytophthora cinnamomi". Molecular Plant Pathology 19, n. 2 (22 agosto 2017): 260–85. http://dx.doi.org/10.1111/mpp.12568.
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3
McDougall, K. L., G. E. St J. Hardy e R. J. Hobbs. "Additions to the host range of Phytophthora cinnamomi in the jarrah (Eucalyptus marginata) forest of Western Australia". Australian Journal of Botany 49, n. 2 (2001): 193. http://dx.doi.org/10.1071/bt99028.
Testo completoAbstract (sommario):
Pathogenicity tests with Phytophthora cinnamomi were conducted on 25 perennial species from the jarrah (Eucalyptus marginata) forest of Western Australia. Most species tested had been found in a separate study to be scarce on sites affected by Phytophthora cinnamomi but frequently found in unaffected vegetation. Some species that were known to be field-tolerant of P. cinnamomi and some that were highly susceptible to infection were included in the study for comparison. Phytophthora cinnamomi was recorded from 13 of 17 species not previously known to be susceptible. Phytophthora cinnamomi was subsequently isolated from dead plants of two of these 13 species in the field. The interpretation of results from the glasshouse trials was difficult for some species because of inconsistent patterns of death and P. cinnamomi isolation in the glasshouse trials. Phytophthora cinnamomi probably causes decline in wild populations of Stylidium amoenum, based on the ease of field and glasshouse isolation of P. cinnamomi and the scarcity of this forb on dieback sites. It may also contribute to decline in populations of Boronia fastigiata, Hybanthus floribundus, Labichea punctata, Scaevola calliptera and Stylidium junceum, although further field sampling is required to confirm this.
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Mora-Sala, Beatriz, Mónica Berbegal e Paloma Abad-Campos. "The Use of qPCR Reveals a High Frequency of Phytophthora quercina in Two Spanish Holm Oak Areas". Forests 9, n. 11 (10 novembre 2018): 697. http://dx.doi.org/10.3390/f9110697.
Testo completoAbstract (sommario):
The struggling Spanish holm oak woodland situation associated with Phytophthora root rot has been studied for a long time. Phytophthora cinnamomi is considered the main, but not the only species responsible for the decline scenario. This study verifies the presence and/or detection of Phytophthora species in two holm oak areas of Spain (southwestern “dehesas” and northeastern woodland) using different isolation and detection approaches. Direct isolation and baiting methods in declining and non-declining holm oak trees revealed Phytophthora cambivora, Phytophthora cinnamomi, Phytophthora gonapodyides, Phytophthora megasperma, and Phytophthora pseudocryptogea in the dehesas, while in the northeastern woodland, no Phytophthora spp. were recovered. Statistical analyses indicated that there was not a significant relationship between the Phytophthora spp. isolation frequency and the disease expression of the holm oak stands in the dehesas. Phytophthora quercina and P. cinnamomi TaqMan real-time PCR probes showed that both P. cinnamomi and P. quercina are involved in the holm oak decline in Spain, but P. quercina was detected in a higher frequency than P. cinnamomi in both studied areas. Thus, this study demonstrates that molecular approaches complement direct isolation techniques in natural and seminatural ecosystem surveys to determine the presence and distribution of Phytophthora spp. This is the first report of P. pseudocryptogea in Europe and its role in the holm oak decline should be further studied.
5
Kurzawińska, H., e I. Gajda. "Fungi isolated from soil with quicksets of Chamaecyparis lawsoniana and their influence on the growth of Phytophthora cinnamomi and Rhizoctonia solani". Plant Protection Science 38, SI 2 - 6th Conf EFPP 2002 (31 dicembre 2017): 631–33. http://dx.doi.org/10.17221/10576-pps.
Testo completoAbstract (sommario):
Chamaecyparis lawsoniana is often attacked by other pathogens (from genera: Phytophthora, Pythium, Fusarium, Rhizoctonia) both when the quicksets are taken root and later, when the young plants are planted. The aim of the study was to determine an effect of saprobiotic fungi isolated from soil with quicksets Chamaecyparis lawsoniana on the growth of Phytophthora cinnamomi and Rhizoctonia solani. In our experiment, method series biotic was used (MAŃKA 1974). This method allowed to determine index of impendence for plants by Phytophthora cinnamomi and Rhizoctonia solani with the help of summary biotic effect. The results of observation on the biotic interaction of saprobiotic fungi isolated from soil with quicksets Chamaecyparis lawsoniana, analysed as biotic series and Phytophthora cinnamomi and Rhizoctonia solani showed, that this of fungal community did not limited growth of these pathogens. Summary biotic effects were negative. Environment of saprobiotic fungi more promoted growth of Rhizoctonia solani than Phytophthora cinnamomi. It means, that in the soil under Chamaecyparis lawsoniana crop, Rhizoctonia solani could have a better of conditions for growth than Phytophthora cinnamomi.
6
McConnell, M. E., e Y. Balci. "Phytophthora cinnamomi as a Contributor to White Oak Decline in Mid-Atlantic United States Forests". Plant Disease 98, n. 3 (marzo 2014): 319–27. http://dx.doi.org/10.1094/pdis-06-13-0649-re.
Testo completoAbstract (sommario):
To evaluate Phytophthora cinnamomi as a cause of white oak (Quercus alba) decline in mid-Atlantic forests, sampling was conducted at 102 sites from 2011 to 2012. Soil and roots from healthy and declining white oak trees were collected. Phytophthora spp. were isolated using baiting and CFU of P. cinnamomi quantified using wet-sieving. Fine roots were scanned and measured. Phytophthora spp. were isolated from 43% of the sites. P. cinnamomi was common; six other species were isolated infrequently. Little difference in lesion size existed on white oak seedlings inoculated with 32 isolates of P. cinnamomi; only 13 isolates caused significant mortality. Soils from white oak versus nine other hosts did not have significantly different CFU. P. cinnamomi was restricted to United States Department of Agriculture hardiness zones six and seven and never found in zone five. The presence of Phytophthora spp. in soil can be associated with white oak fine root health. When Phytophthora spp. were present, white oak trees in zones five and six had less fine roots. In mid-Atlantic oak forests, however, environmental conditions appear to play a key role in determining the impact of P. cinnamomi on the root system. P. cinnamomi alone does not appear to be a causal factor of white oak decline.
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Balci, Y., S. Balci, J. Eggers, W. L. MacDonald, J. Juzwik, R. P. Long e K. W. Gottschalk. "Phytophthora spp. Associated with Forest Soils in Eastern and North-Central U.S. Oak Ecosystems". Plant Disease 91, n. 6 (giugno 2007): 705–10. http://dx.doi.org/10.1094/pdis-91-6-0705.
Testo completoAbstract (sommario):
A survey of soils associated with oak species was conducted in 2003 and 2004 in Indiana, Illinois, Maryland, Michigan, Minnesota, Pennsylvania, Ohio, West Virginia, and Wisconsin to investigate the occurrence of Phytophthora spp. Soils taken from around the base of healthy and declining oak trees were flooded with H2O and Quercus robur leaflets were used as bait for Phytophthora spp. From 829 soil samples collected near trees, 21% were positive for Phytophthora spp., with 55% of the 125 sites surveyed yielding a Phytophthora sp. Phytophthora cinnamomi was the most frequently isolated species, representing 69.4% of the Phytophthora-infested sites surveyed. Other species, in decreasing order of isolation frequency were Phytophthora sp. 2, P. citricola, P. europaea, P. cambivora, P. quercina-like isolates, and Phytophthora sp. 1. No significant association was found between the presence of Phytophthora organisms and site characteristics such as latitude, elevation, soil pH, or the crown condition of the trees. However, in P. cinnamomi-infested sites, a significant association was found with the deteriorating crown status of Q. alba and the presence of P. cinnamomi. The absence of P. cinnamomi above the 40°N latitude range also was noteworthy.
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Juhásová, G., e S. Bernadovičová. "Efficacy of biofungicides Supresivit and Polyversum against Phytophthora root pathogens on European chestnut (Castanea sativa Mill.)". Horticultural Science 31, No. 3 (25 novembre 2011): 109–14. http://dx.doi.org/10.17221/3802-hortsci.
Testo completoAbstract (sommario):
The effect of two commercially produced biopreparations on the originators of chestnut ink disease in Slovakia – soil fungi Phytophthora cambivora and Phytophthora cinnamomi was tested in laboratory conditions. Investigations of interrelations between Trichoderma harzianum (Pythium oligandrum) and isolates of Phytophthora sp. obtained from infected tissues of Castanea sativa Mill. proved more important inhibitive effects for Pythium oligandrum (biopreparation Polyversum) efficiency 25.3% (Ph. cambivora) and 26.2% (Ph. cinnamomi). Biopreparation Supresivit (Trichoderma harzianum) reached the efficiency 9.1% for Ph. cambivora isolates and 9.2% for Ph. cinnamomi isolates. Significant effect of the used bioformulas for inhibition of mycelial growth of both Phytophthora sp. and significant difference in the efficacy of two different bioformulas were confirmed statistically.
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Agapito Amador, María Eugenia, Víctor David Cibrián-Llanderal, Mónica Gutiérrez Rojas, Daniel Ruiz-Juárez, Betzabe Ebenhezer López Corona e Edgar Omar Rueda-Puente. "Phytophthora cinnamomi Rands en aguacate". Revista Mexicana de Ciencias Agrícolas, n. 28 (22 settembre 2022): 331–41. http://dx.doi.org/10.29312/remexca.v13i28.3287.
Testo completoAbstract (sommario):
El objetivo de la presente revisión es dar a conocer el estatus epidemiológico de Phytophthora cinnamomi Rands en interacción con Persea americana Mill. y las alternativas de manejo fitosanitario autorizadas. El ensayo se realizó con base en reportes de instancias oficiales y científicas en materia de sanidad vegetal, de brotes epidemiológicos de la enfermedad tristeza del aguacate causada por P. cinnamomi. A nivel mundial, la pérdida de árboles de aguacate fue exponencial, debido a la enfermedad causada por el oomiceto P. cinnamomi quien presentó comportamiento epidemiológico a nivel nacional e internacional. En 1942, en Puerto Rico el patógeno fue aislado por primera vez por Tucker en plantas de aguacate. En México, el primer brote epidemiológico por este patógeno fue en 1952, con pérdidas de 90% de la producción de aguacate, la distribución de la enfermedad se expandió a diferentes partes del mundo. En condiciones favorables afecta la raíz y base de la corona, invade haces vasculares y toma los nutrientes para su desarrollo. La patogénesis es influenciada por la temperatura, precipitación, humedad, pH, disponibilidad de nutrientes y textura del suelo. En campo, la efectividad biológica de las moléculas, para el control del oomiceto, puede presentar limitantes que impactan en la microbiota, flora y fauna; además, de los efectos que se reflejan en la calidad e inocuidad de frutos por la acumulación de moléculas de plaguicidas sintéticos. Dada la situación fitosanitaria que expresa la producción de aguacate es necesario implementar alternativas de manejo sustentable, como la endoterapia, a través de la inyección de productos selectivos en dosis específicas, que controlen a la enfermedad sin afectar la calidad e inocuidad del fruto.
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Joubert, Melissa, Robert Backer, Juanita Engelbrecht e Noëlani van den Berg. "Expression of several Phytophthora cinnamomi putative RxLRs provides evidence for virulence roles in avocado". PLOS ONE 16, n. 7 (14 luglio 2021): e0254645. http://dx.doi.org/10.1371/journal.pone.0254645.
Testo completoAbstract (sommario):
Phytophthora cinnamomi is a plant pathogenic oomycete that causes Phytophthora root rot of avocado (PRR). Currently, there is a limited understanding of the molecular interactions underlying this disease. Other Phytophthora species employ an arsenal of effector proteins to manipulate host physiology, of which the RxLR effectors contribute to virulence by interfering with host immune responses. The aim of this study was to identify candidate RxLR effectors in P. cinnamomi that play a role in establishing PRR, and to infer possible functions for these effectors. We identified 61 candidate RxLR genes which were expressed during infection of a susceptible avocado rootstock. Several of these genes were present in multiple copies in the P. cinnamomi genome, suggesting that they may contribute to pathogen fitness. Phylogenetic analysis of the manually predicted RxLR protein sequences revealed 12 P. cinnamomi RxLRs that were related to characterised effectors in other Phytophthora spp., providing clues to their functions in planta. Expression profiles of nine more RxLRs point to possible virulence roles in avocado–highlighting a way forward for studies of this interaction. This study represents the first investigation of the expression of P. cinnamomi RxLR genes during the course of avocado infection, and puts forward a pipeline to pinpoint effector genes with potential as virulence determinants, providing a foundation for the future functional characterization of RxLRs that contribute to P. cinnamomi virulence in avocado.
Tesi sul tema "Phytophthora cinnamomi"
1
Finlay, Annabelle Ruth. "Microbial suppression of Phytophthora cinnamomi". Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317116.
Testo completo
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King, Michaela. "The phosphite responsive transcriptome of phytophthora cinnamomi". Thesis, King, Michaela (2007) The phosphite responsive transcriptome of phytophthora cinnamomi. PhD thesis, Murdoch University, 2007. https://researchrepository.murdoch.edu.au/id/eprint/132/.
Testo completoAbstract (sommario):
Phosphite has been used to effectively control the soil borne plant pathogen Phytophthora cinnamomi in many horticultural crops, forest trees and natural ecosystems. However, the molecular mechanisms behind phosphite action on this pathogen are poorly understood.
Several studies have shown that phosphite inhibits growth and zoospore production of P. cinnamomi and in addition induces significant physiological and metabolic changes in the mycelium. As an approach to understanding the mechanisms and relevance of these changes in the pathogen, the effect of phosphite on gene expression was investigated using microarray analysis. To construct the microarray, RNA was extracted from phosphite-treated (40 ug/ml) mycelium of P. cinnamomi isolate MP 80. The chosen phosphite concentration inhibited the mycelial growth by 70% but provided sufficient mycelium for RNA extractions after 4 days growth at 25C.
The mRNA was reverse transcribed into cDNA and cloned into lambda to construct a library consisting of 2 million pfu of which 80 % were recombinant phage. The inserts were sequenced for a random selection of clones from the library. The nucleotide sequences generated revealed a range of different P. cinnamomi genes being expressed and demonstrated that the cDNA library provided a good representation of the transcripts expressed in P. cinnamomi. The types of genes found to be expressed in the mycelium of P. cinnamomi included genes encoding GTP binding proteins involved in vesicle transport, structural proteins involved in maintaining cell membrane integrity,elicitors, phosphatases and ribosomal proteins.
Over nine thousand cDNA transcripts were randomly selected from the cDNA library and prepared by PCR amplification and purification for microarray construction. Custom made cDNA arrays containing 9216 cDNA transcripts were constructed and probed with RNA from untreated mycelium and mycelium grown in medium with 40 ug/ml phosphite.
Two genes, EF-1 alpha and cinnamomin gene, identified by qRT-PCR as being constitutively expressed were also positioned on the arrays as positive controls. In the process of identifying constitutively expressed genes, qRT PCR revealed that phosphite down-regulated a gene encoding ubiquitin-conjugating enzyme, a component of the ubiquitin/proteasome pathway involved in the removal of abnormal and short lived-regulatory proteins and rate limiting enzymes.
From the arrays a further seventy-two transcripts with altered patterns in gene expression (fold change > 2) were identified. The majority of the cDNA transcripts spotted on the array were down-regulated with changes in gene expression ranging from 2- to 3.5-fold. Thirty-two cDNA transcripts were up-regulated with changes in gene expression ranging from 2- to 16-fold. Characterisation by sequencing revealed that the most highly induced transcripts coded for ADP-ribosylation factors, an ABC cassette transporter and a glycosyl transferase. A transcript encoding a vitamin B6 biosynthesis protein was also identified as up-regulated by 2.9-fold. In contrast, the down-regulated transcripts coded for cellulose synthase I, annexin, glutamine synthetase, metallothionein and an alternative oxidase. The results are discussed in terms of possible roles and mechanism(s) of phosphite action within the mycelium of P.cinnamomi.
This work is the first comprehensive screen for phosphite regulated-gene expression in P. cinnamomi and represents a significant step towards an understanding of the mode of action of phosphite on this organism. This thesis provides valuable information on the molecular interaction between phosphite and P. cinnamomi, which in future studies may stimulate the discovery of novel methods and cellular targets for the control of plant pathogenic Oomycetes.
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King, Michaela. "The phosphite responsive transcriptome of Phytophthora cinnamomi /". King, Michaela (2007) The phosphite responsive transcriptome of phytophthora cinnamomi. PhD thesis, Murdoch University, 2007. http://researchrepository.murdoch.edu.au/132/.
Testo completoAbstract (sommario):
Phosphite has been used to effectively control the soil borne plant pathogen Phytophthora cinnamomi in many horticultural crops, forest trees and natural ecosystems. However, the molecular mechanisms behind phosphite action on this pathogen are poorly understood.
Several studies have shown that phosphite inhibits growth and zoospore production of P. cinnamomi and in addition induces significant physiological and metabolic changes in the mycelium. As an approach to understanding the mechanisms and relevance of these changes in the pathogen, the effect of phosphite on gene expression was investigated using microarray analysis. To construct the microarray, RNA was extracted from phosphite-treated (40 ug/ml) mycelium of P. cinnamomi isolate MP 80. The chosen phosphite concentration inhibited the mycelial growth by 70% but provided sufficient mycelium for RNA extractions after 4 days growth at 25C.
The mRNA was reverse transcribed into cDNA and cloned into lambda to construct a library consisting of 2 million pfu of which 80 % were recombinant phage. The inserts were sequenced for a random selection of clones from the library. The nucleotide sequences generated revealed a range of different P. cinnamomi genes being expressed and demonstrated that the cDNA library provided a good representation of the transcripts expressed in P. cinnamomi. The types of genes found to be expressed in the mycelium of P. cinnamomi included genes encoding GTP binding proteins involved in vesicle transport, structural proteins involved in maintaining cell membrane integrity,elicitors, phosphatases and ribosomal proteins.
Over nine thousand cDNA transcripts were randomly selected from the cDNA library and prepared by PCR amplification and purification for microarray construction. Custom made cDNA arrays containing 9216 cDNA transcripts were constructed and probed with RNA from untreated mycelium and mycelium grown in medium with 40 ug/ml phosphite.
Two genes, EF-1 alpha and cinnamomin gene, identified by qRT-PCR as being constitutively expressed were also positioned on the arrays as positive controls. In the process of identifying constitutively expressed genes, qRT PCR revealed that phosphite down-regulated a gene encoding ubiquitin-conjugating enzyme, a component of the ubiquitin/proteasome pathway involved in the removal of abnormal and short lived-regulatory proteins and rate limiting enzymes.
From the arrays a further seventy-two transcripts with altered patterns in gene expression (fold change > 2) were identified. The majority of the cDNA transcripts spotted on the array were down-regulated with changes in gene expression ranging from 2- to 3.5-fold. Thirty-two cDNA transcripts were up-regulated with changes in gene expression ranging from 2- to 16-fold. Characterisation by sequencing revealed that the most highly induced transcripts coded for ADP-ribosylation factors, an ABC cassette transporter and a glycosyl transferase. A transcript encoding a vitamin B6 biosynthesis protein was also identified as up-regulated by 2.9-fold. In contrast, the down-regulated transcripts coded for cellulose synthase I, annexin, glutamine synthetase, metallothionein and an alternative oxidase. The results are discussed in terms of possible roles and mechanism(s) of phosphite action within the mycelium of P.cinnamomi.
This work is the first comprehensive screen for phosphite regulated-gene expression in P. cinnamomi and represents a significant step towards an understanding of the mode of action of phosphite on this organism. This thesis provides valuable information on the molecular interaction between phosphite and P. cinnamomi, which in future studies may stimulate the discovery of novel methods and cellular targets for the control of plant pathogenic Oomycetes.
4
au, M. King@murdoch edu, e Michaela King. "The phosphite responsive transcriptome of phytophthora cinnamomi". Murdoch University, 2007. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20080526.104656.
Testo completoAbstract (sommario):
Phosphite has been used to effectively control the soil borne plant pathogen Phytophthora cinnamomi in many horticultural crops, forest trees and natural ecosystems. However, the molecular mechanisms behind phosphite action on this pathogen are poorly understood.
Several studies have shown that phosphite inhibits growth and zoospore production of P. cinnamomi and in addition induces significant physiological and metabolic changes in the mycelium. As an approach to understanding the mechanisms and relevance of these changes in the pathogen, the effect of phosphite on gene expression was investigated using microarray analysis. To construct the microarray, RNA was extracted from phosphite-treated (40 ug/ml) mycelium of P. cinnamomi isolate MP 80. The chosen phosphite concentration inhibited the mycelial growth by 70% but provided sufficient mycelium for RNA extractions after 4 days growth at 25C.
The mRNA was reverse transcribed into cDNA and cloned into lambda to construct a library consisting of 2 million pfu of which 80 % were recombinant phage. The inserts were sequenced for a random selection of clones from the library. The nucleotide sequences generated revealed a range of different P. cinnamomi genes being expressed and demonstrated that the cDNA library provided a good representation of the transcripts expressed in P. cinnamomi. The types of genes found to be expressed in the mycelium of P. cinnamomi included genes encoding GTP binding proteins involved in vesicle transport, structural proteins involved in maintaining cell membrane integrity,elicitors, phosphatases and ribosomal proteins.
Over nine thousand cDNA transcripts were randomly selected from the cDNA library and prepared by PCR amplification and purification for microarray construction. Custom made cDNA arrays containing 9216 cDNA transcripts were constructed and probed with RNA from untreated mycelium and mycelium grown in medium with 40 ug/ml phosphite.
Two genes, EF-1 alpha and cinnamomin gene, identified by qRT-PCR as being constitutively expressed were also positioned on the arrays as positive controls. In the process of identifying constitutively expressed genes, qRT PCR revealed that phosphite down-regulated a gene encoding ubiquitin-conjugating enzyme, a component of the ubiquitin/proteasome pathway involved in the removal of abnormal and short lived-regulatory proteins and rate limiting enzymes.
From the arrays a further seventy-two transcripts with altered patterns in gene expression (fold change > 2) were identified. The majority of the cDNA transcripts spotted on the array were down-regulated with changes in gene expression ranging from 2- to 3.5-fold. Thirty-two cDNA transcripts were up-regulated with changes in gene expression ranging from 2- to 16-fold. Characterisation by sequencing revealed that the most highly induced transcripts coded for ADP-ribosylation factors, an ABC cassette transporter and a glycosyl transferase. A transcript encoding a vitamin B6 biosynthesis protein was also identified as up-regulated by 2.9-fold. In contrast, the down-regulated transcripts coded for cellulose synthase I, annexin, glutamine synthetase, metallothionein and an alternative oxidase. The results are discussed in terms of possible roles and mechanism(s) of phosphite action within the mycelium of P.cinnamomi.
This work is the first comprehensive screen for phosphite regulated-gene expression in P. cinnamomi and represents a significant step towards an understanding of the mode of action of phosphite on this organism. This thesis provides valuable information on the molecular interaction between phosphite and P. cinnamomi, which in future studies may stimulate the discovery of novel methods and cellular targets for the control of plant pathogenic Oomycetes.
5
Reitmann, Anandi. "Identification of pathogenicity genes in Phytophthora cinnamomi". Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/79179.
Testo completo
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Gilovitz, Joshua. "Screening Lambertia for resistance to Phytophthora cinnamomi". Thesis, Gilovitz, Joshua (2007) Screening Lambertia for resistance to Phytophthora cinnamomi. Honours thesis, Murdoch University, 2007. https://researchrepository.murdoch.edu.au/id/eprint/32597/.
Testo completo
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Wheeler, Margaret Anne. "Reproductive and molecular biology of Eucalyptus marginata Donn ex Smith /". Access via Murdoch University Digital Theses Project, 2003. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040723.140250.
Testo completo
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McCarren, Kathryn. "Saprophytic ability and the contribution of chlamydospores and oospores to the survival of Phytophthora cinnamomi". Thesis, McCarren, Kathryn (2006) Saprophytic ability and the contribution of chlamydospores and oospores to the survival of Phytophthora cinnamomi. PhD thesis, Murdoch University, 2006. https://researchrepository.murdoch.edu.au/id/eprint/190/.
Testo completoAbstract (sommario):
Phytophthora cinnamomi has been recognised as a key threatening process to Australia's biodiversity by the Commonwealth's Environment Protection and Biodiversity Conservation Act 1999. Despite over 80 years of extensive research, its exact mode of survival is still poorly understood. It is widely accepted that thin- and thick-walled chlamydospores are the main survival propagules while oospores are assumed to play no role in the survival of the pathogen in the Australian environment, yet evidence is limited. The saprophytic ability of the pathogen is still unresolved despite the important role this could play in the ability of the pathogen to survive in the absence of susceptible hosts. This thesis aimed to investigate chlamydospores, oospores and the saprophytic ability of P. cinnamomi to determine their contribution to survival.
Phytophthora cinnamomi did not show saprophytic ability in non-sterile soils. The production of thick-walled chlamydospores and selfed oospores of P. cinnamomi in vitro was documented. Thick-walled chlamydospores were sporadically formed under sterile and non-sterile conditions in vitro but exact conditions for stimulating their formation could not be determined. The formation of thick-walled chlamydospores emerging from mycelium of similar wall thickness was observed, challenging the current knowledge of chlamydospore formation.
Selfed oospores were abundant in vitro on modified Ribeiro's minimal medium in one isolate. Three other isolates tested also produced oospores but not in large numbers. Although the selfed oospores did not germinate on a range of media, at least 16 % were found to be viable using Thiozolyl Blue Tetrazolium Bromide staining and staining of the nuclei with 4', 6-diamidino-2-phenylindole.2HCl (DAPI). This indicated the potential of selfed oospores as survival structures and their ability to exist dormantly.
The ability of phosphite to kill chlamydospores and selfed oospores was studied in vitro. Results challenged the efficacy of this chemical and revealed the necessity for further study of its effect on survival propagules of P. cinnamomi in the natural environment. Phosphite was shown to induce dormancy in thin-walled chlamydospores if present during their formation in vitro. Interestingly, dormancy was only induced by phosphite in isolates previously reported as sensitive to phosphite and not those reported as tolerant.
Chlamydospores were produced uniformly across the radius of the colony on control modified Ribeiro's minimal medium but on medium containing phosphite (40 or 100 mcg ml-1), chlamydospore production was initially inhibited before being stimulated during the log phase of growth. This corresponded to a point in the colony morphology where mycelial density changed from tightly packed mycelium to sparse on medium containing phosphite. This change in morphology did not occur when the pathogen was grown on liquid media refreshed every four days, and chlamydospores were evenly distributed across the radius of these colonies. This trend was not observed in selfed oospores produced in the presence of phosphite. Selfed oospore production was found to be inhibited by phosphite at the same concentrations that stimulated chlamydospore production.
Isolates of P. cinnamomi were transformed using a protoplast/ polyethylene glycol method to contain the Green Fluorescent Protein and geneticin resistance genes to aid in future studies on survival properties of the organism. Although time constraints meant the stability of the transgene could not be determined, it was effective in differentiating propagules of the transformed P. cinnamomi from spores of other microrganisms in a non-sterile environment. Two different sized chlamydospores (approximately 30 mcg diameter and < 20 mcg diameter) were observed in preliminary trials of transformed P. cinnamomi inoculated lupin roots floated in non-sterile soil extracts and these were easily distinguished from microbial propagules of other species. The growth and pathogenicity was reduced in two putative transformants and their ability to fluoresce declined over ten subcultures but they still remained resistant to geneticin.
This study has improved our knowledge on the survival abilities of P. cinnamomi in vitro and has provided a useful tool for studying these abilities under more natural glasshouse conditions. Important implications of phosphite as a control have been raised.
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McCarren, Kathryn. "Saprophytic ability and the contribution of chlamydospores and oospores to the survival of Phytophthora cinnamomi". McCarren, Kathryn (2006) Saprophytic ability and the contribution of chlamydospores and oospores to the survival of Phytophthora cinnamomi. PhD thesis, Murdoch University, 2006. http://researchrepository.murdoch.edu.au/190/.
Testo completoAbstract (sommario):
Phytophthora cinnamomi has been recognised as a key threatening process to Australia's biodiversity by the Commonwealth's Environment Protection and Biodiversity Conservation Act 1999. Despite over 80 years of extensive research, its exact mode of survival is still poorly understood. It is widely accepted that thin- and thick-walled chlamydospores are the main survival propagules while oospores are assumed to play no role in the survival of the pathogen in the Australian environment, yet evidence is limited. The saprophytic ability of the pathogen is still unresolved despite the important role this could play in the ability of the pathogen to survive in the absence of susceptible hosts. This thesis aimed to investigate chlamydospores, oospores and the saprophytic ability of P. cinnamomi to determine their contribution to survival.
Phytophthora cinnamomi did not show saprophytic ability in non-sterile soils. The production of thick-walled chlamydospores and selfed oospores of P. cinnamomi in vitro was documented. Thick-walled chlamydospores were sporadically formed under sterile and non-sterile conditions in vitro but exact conditions for stimulating their formation could not be determined. The formation of thick-walled chlamydospores emerging from mycelium of similar wall thickness was observed, challenging the current knowledge of chlamydospore formation.
Selfed oospores were abundant in vitro on modified Ribeiro's minimal medium in one isolate. Three other isolates tested also produced oospores but not in large numbers. Although the selfed oospores did not germinate on a range of media, at least 16 % were found to be viable using Thiozolyl Blue Tetrazolium Bromide staining and staining of the nuclei with 4', 6-diamidino-2-phenylindole.2HCl (DAPI). This indicated the potential of selfed oospores as survival structures and their ability to exist dormantly.
The ability of phosphite to kill chlamydospores and selfed oospores was studied in vitro. Results challenged the efficacy of this chemical and revealed the necessity for further study of its effect on survival propagules of P. cinnamomi in the natural environment. Phosphite was shown to induce dormancy in thin-walled chlamydospores if present during their formation in vitro. Interestingly, dormancy was only induced by phosphite in isolates previously reported as sensitive to phosphite and not those reported as tolerant.
Chlamydospores were produced uniformly across the radius of the colony on control modified Ribeiro's minimal medium but on medium containing phosphite (40 or 100 mcg ml-1), chlamydospore production was initially inhibited before being stimulated during the log phase of growth. This corresponded to a point in the colony morphology where mycelial density changed from tightly packed mycelium to sparse on medium containing phosphite. This change in morphology did not occur when the pathogen was grown on liquid media refreshed every four days, and chlamydospores were evenly distributed across the radius of these colonies. This trend was not observed in selfed oospores produced in the presence of phosphite. Selfed oospore production was found to be inhibited by phosphite at the same concentrations that stimulated chlamydospore production.
Isolates of P. cinnamomi were transformed using a protoplast/ polyethylene glycol method to contain the Green Fluorescent Protein and geneticin resistance genes to aid in future studies on survival properties of the organism. Although time constraints meant the stability of the transgene could not be determined, it was effective in differentiating propagules of the transformed P. cinnamomi from spores of other microrganisms in a non-sterile environment. Two different sized chlamydospores (approximately 30 mcg diameter and < 20 mcg diameter) were observed in preliminary trials of transformed P. cinnamomi inoculated lupin roots floated in non-sterile soil extracts and these were easily distinguished from microbial propagules of other species. The growth and pathogenicity was reduced in two putative transformants and their ability to fluoresce declined over ten subcultures but they still remained resistant to geneticin.
This study has improved our knowledge on the survival abilities of P. cinnamomi in vitro and has provided a useful tool for studying these abilities under more natural glasshouse conditions. Important implications of phosphite as a control have been raised.
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Pilbeam, Ros. "Effects of phosphite on disease development and histological responses in Eucalyptus marginata infected with Phytophthora cinnamomi". Thesis, Pilbeam, Ros (2003) Effects of phosphite on disease development and histological responses in Eucalyptus marginata infected with Phytophthora cinnamomi. PhD thesis, Murdoch University, 2003. https://researchrepository.murdoch.edu.au/id/eprint/260/.
Testo completoAbstract (sommario):
Phosphite is currently used for the management of Phytophthora cinnamomi in native plant communities. A greater understanding of how phosphite affects the host-pathogen interaction is required in order to determine the most effective treatment. This thesis aimed to investigate the effects of applied phosphite concentration on phytotoxicity, in planta concentration of phosphite, disease development and anatomical responses of Eucalyptus marginata.
Spraying the foliage to run-off with 7.5 and 10 g phosphite/L led to the development of severe leaf necrosis within 7 days, with greater than 60% of the leaf area damaged. Moderate phytotoxicity was observed after treatment with 5 g phosphite/L. In planta concentration of phosphite in stems, lignotubers and roots did not differ significantly between applied concentrations of phosphite.
Stem tissue contained the largest concentration of phosphite at one week after spraying, with approximately 210 and 420 g phosphite/g dry weight detected after treatment with 5 and 10 g phosphite/L, respectively. In a subsequent field trial, the applied concentration of phosphite was found to affect the duration of effectiveness of phosphite in protecting E. marginata seedlings from stem colonisation by P. cinnamomi. Plants were wound-inoculated with P. cinnamomi at 6-monthly intervals after spraying with phosphite. The 2.5 and 5 g phosphite/L treatments were effective against colonisation by P. cinnamomi when inoculated 0 and 6 months after spraying, but only the 5 g phosphite/L treatment inhibited P. cinnamomi within 12 months of spraying. Phosphite had no effect on colonisation by P. cinnamomi when plants were inoculated at 17 months after spraying. The in planta concentration of phosphite detected in the leaves, stems and roots of plants treated with 5 g phosphite/L did not differ significantly between the time of harvest or tissue type at 0.2 and 6 months after spraying. P. cinnamomi remained viable in plants treated with phosphite.Treatment with 2.5 and 5 g phosphite/L when P. cinnamomi was well established in the stems was ineffective at preventing the death of E. marginata.
Between 45 and 89% of plants were girdled on the day of spraying. Spraying plants with 2.5 and 5 g phosphite/L when conditions were less favourable for the pathogen reduced the mortality of E. marginata for up to 10 months.
E. marginata seedlings responded to damage by P. cinnamomi with the production of kino veins and woundwood. Bark lesions were in the process of being sloughed off by 7 months after inoculation in plants that remained alive. In plants of a resistant (RR) clonal line and susceptible (SS) clonal line, phosphite treatment inhibited lesion extension in stems, but lesions did not indicate the amount of stem colonised by P. cinnamomi. The pathogen was isolated from up to 17 cm beyond the lesion front in the RR clonal line. Treatments that reduced the mortality of E. marginata were 5 g phosphite/L in the RR clonal line (RR/5) and 10 g phosphite/L in the SS clonal line (SS/10).
Uninoculated plants were wounded with liquid nitrogen to determine the microscopic responses to injury in the absence of the pathogen. Wound closure was achieved within 21 days of wounding, with callus formation and vascular cambium regeneration. A wound periderm separated wounded tissue from healthy tissue, adjacent to a lignified boundary zone. Two types of phellem were observed - thin-walled phellem (TnP) and thick-walled phellem (TkP). The first-formed TnP layers contained variable-shaped cells, while subsequent layers were more cubical in shape. Multiple TnP layers developed up to 42 days after wounding, with TkP cells sandwiched between the TnP layers. Genotype and phosphite treatment did not affect the wound responses.
Inoculated plants with a restricted lesion extension also formed a wound periderm to separate damaged tissue from healthy tissue. Phosphite treatment stimulated the responses to P. cinnamomi in both clonal lines. Early development of the wound periderm was visible by 6 days after phosphite treatment. It waspreceded by the formation of a ligno-suberised boundary zone in the cambial zone and in phloem parenchyma cells existing prior to injury. Suberin was not detected in the SS/0 treatment. TnP layers completely surrounded lesioned tissue in plants still alive by 24 days after phosphite treatment. Extensive callus production was evident in the SS/10, RR/5 and RR/10 treatments.
Temperature affected the post-inoculation efficacy of phosphite and anatomical responses of E. marginata. At 20 degrees C lesion extension was restricted in both clonal lines of E. marginata, irrespective of phosphite treatment. Greater than 70% of inoculated plants in all treatments produced a ligno-suberised boundary zone at 20 degrees C and between 30 and 70% formed a wound periderm. At 28 degrees C, lesion extension was reduced in phosphite-treated plants at 7 days after treatment. However, lesions continued to extend up to 5 mm per day in the SS clonal line and very few SS plants formed a wound periderm at the lesion front. This contrasted with the strong responses to abiotic wounding observed in uninoculated SS plants at 28 degrees C. The most extensive responses to P. cinnamomi were detected in the RR/5 treatment at 28 degrees C, with a ligno-suberised boundary zone and differentiated TnP of a wound periderm observed in greater than 70% of plants. This treatment resulted in significantly less girdled plants than all other treatments at 28 degrees C, including the RR/0 treatment. At 23 and 24 degrees C, there was no significant difference in acropetal lesion extension or circumferential lesion spread between clonal lines. The inoculation technique and environmental conditions may have resulted in too high a disease pressure for a full expression of resistance in the RR clonal line.
This thesis demonstrates that phosphite has the potential to enhance the resistance of young E. marginata and enable them to survive infection by P. cinnamomi. However, its effectiveness is dependent upon a number of factors, including host resistance, environmental conditions, the applied phosphite concentration and the timing of application.
Libri sul tema "Phytophthora cinnamomi"
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Paul, Gadek, Worboys Stuart e Cooperative Research Centre for Tropical Rainforest Ecology and Management., a cura di. Rainforest dieback mapping and assessment: Phytophthora species diversity and impacts of dieback on rainforest canopies. Cairns, Qld: Rainforest CRC, 2003.
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2
Hardy, Giles E. St. J., a cura di. The potential of the fungicide phosphite to control Phytophthora cinnamomi in native plant communities associated with mining. East Perth, WA: MERIWA, 2000.
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3
Shearer, B. L. Jarrah dieback: The dynamics and management of Phytophthora cinnamomi in the jarrah (Eucalyptus marginata) forest of south-western Australia. Como, W.A: Dept. of Conservation and Land Management, 1989.
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Gardner, J. H. Phytophthora cinnamomi in operational and rehabilitated bauxite mine areas in south-western Australia. S.l: s.n, 1987.
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5
Tainter, Frank H. Annotated bibliography of littleleaf and tree decline diseases caused by Phytophthora cinnamomi rands. Clemson, S.C: Clemson University, College of Forest and Recreation Resources, 1987.
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Morgan, Lucy. Gift from the hills: Miss Lucy Morgan's story of her unique Penland School. 2a ed. Penland, N.C: Penland School of Crafts, 2005.
Cerca il testo completoCapitoli di libri sul tema "Phytophthora cinnamomi"
1
Dell, B., e N. Malajczuk. "Jarrah dieback — A disease caused by Phytophthora cinnamomi". In The Jarrah Forest, 67–87. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-3111-4_6.
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2
Gubler, Frank, e Adrienne R. Hardham. "The Fate of Peripheral Vesicles in Zoospores of Phytophthora cinnamomi During Infection of Plants". In Electron Microscopy of Plant Pathogens, 197–210. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-75818-8_15.
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3
Garkaklis, M. J., M. C. Calver, B. A. Wilson e G. E. St J. Hardy. "Habitat alteration caused by an introduced plant disease, Phytophthora cinnamomi: a potential threat to the conservation of Australian forest fauna". In Conservation of Australia's Forest Fauna, 899–913. P.O. Box 20, Mosman NSW 2088: Royal Zoological Society of New South Wales, 2004. http://dx.doi.org/10.7882/fs.2004.899.
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"PROTOCOL 01-15.1: Qualitative and quantitative recovery of Phytophthora cinnamomi from soil". In Laboratory Protocols for Phytophthora Species, a cura di Kelly Ivors, 1–2. The American Phytopathological Society, 2015. http://dx.doi.org/10.1094/9780890544969.01.15.1.
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Bishop, T., R. Daniel, D. Guest, M. Nelson e C. Chang. "A digital soil map of Phytophthora cinnamomi in the Gondwana Rainforests of eastern Australia". In Digital Soil Assessments and Beyond, 65–68. CRC Press, 2012. http://dx.doi.org/10.1201/b12728-15.
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Zareen Ghafoor, Gul, Memuna Ghafoor Shahid, Maryam Ali e Naghmana Ghafoor. "Ecosystem Services in the Changing Climate: Calling Attention for the Conservation of Tropical and Subtropical Forests". In Tropical Forests - Ecology, Diversity and Conservation Status [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.109800.
Testo completoAbstract (sommario):
Tropical and subtropical forests have diverse ecological functions but are most disturbed due to climatic changes. Peer-reviewed articles, books and reports were searched and downloaded to analyze the effect of climatic changes on tropical and subtropical forests and highlight the need for conservation efforts to ensure sustainable supply of ecosystem services. These forests store largest share (55%) of global terrestrial carbon pool. But the projected rise in temperature (4oC), CO2 levels (495 ppm) and changes in precipitation regime by 2100 are expected to cause significant changes in ecosystem productivity and nutrient turnover rate making forests more vulnerable to climate change. High temperature with low rainfall reduces tree growth, increases soil carbon fluxes by accelerating rate of nutrient cycling, restricts the range of pollinators and increases pest infestation (Phytophthora cinnamomi) affecting ecosystem health and future food security. Increase in heat waves increase the incidence of wild fires and degrade ecosystem quality. Climate change also reduces the scenic beauty, ecotourism and associated economic and mental health benefits. Proactive measures must be taken to mitigate the likely causes of climate change and efforts should be taken to conserve the existing forest reserves to ensure sustainable supply of the ecosystem services.
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del Pilar Rodríguez Guzmán, María. "Soil Biodiversity and Root Pathogens in Agroecosystems". In Biodiversity of Ecosystems [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99317.
Testo completoAbstract (sommario):
Soil ecosystem is a living and dynamic environment, habitat of thousands of microbial species, animal organisms and plant roots, integrated all of them in the food webs, and performing vital functions like organic matter decomposition and nutrient cycling; soil is also where plant roots productivity represent the main and first trophic level (producers), the beginning of the soil food web and of thousands of biological interactions. Agroecosystems are modified ecosystems by man in which plant, animal and microorganisms biodiversity has been altered, and sometimes decreased to a minimum number of species. Plant diseases, including root diseases caused by soil-borne plant pathogens are important threats to crop yield and they causes relevant economic losses. Soil-borne plant pathogens and the diseases they produce can cause huge losses and even social and environmental changes, for instance the Irish famine caused by Phytophthora infestans (1845–1853), or the harmful ecological alterations in the jarrah forests of Western Australia affected by Phytophthora cinnamomi in the last 100 years. How can a root pathogen species increase its populations densities at epidemic levels? In wild ecosystems usually we expect the soil biodiversity (microbiome, nematodes, mycorrhiza, protozoa, worms, etc.) through the trophic webs and different interactions between soil species, are going to regulate each other and the pathogens populations, avoiding disease outbreaks. In agroecosystems where plant diseases and epidemics are frequent and destructive, soil-borne plant pathogens has been managed applying different strategies: chemical, cultural, biological agents and others; however so far, there is not enough knowledge about how important is soil biodiversity, mainly microbiome diversity and soil food webs structure and function in the management of root pathogens, in root and plant health, in healthy food production, and maybe more relevant in the conservation of soil as a natural resource and derived from it, the ecosystem services important for life in our planet.
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Ávila Murillo, Mónica Constanza, Erika Andrea Plazas Gonzales, Wilman Antonio Delgado Ávila e Luis Enrique Cuca Suarez. "Lauráceas como fuente de control de enfermedades de frutas tropicales. Modelo Phytophthora cinnamomi, “tristeza del aguacatero”". In Gulupa (Passiflora edulis), curuba (Passiflora tripartita), aguacate (Persea americana) y tomate de árbol (Solanum betaceum) Innovaciones, 229–49. Centro editorial Facultad de Ciencias, 2019. http://dx.doi.org/10.36385/fcbog-1-13.
Testo completoAtti di convegni sul tema "Phytophthora cinnamomi"
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Matei, Petruta Mihaela, Laura Buzón-Durán, Eduardo Pérez-Lebeña, Jesús Martín-Gil, Beatrice Michaela Iacomi, María del Carmen Ramos-Sánchez e Pablo Martín-Ramos. "Estudio de la actividad antifúngica in vitro de materiales compuestos basados en complejos de inclusión de polifenoles contra Phytophthora cinnamomi". In X Congreso Ibérico de Agroingeniería = X Congresso Ibérico de Agroengenharia. Zaragoza: Servicio de Publicaciones Universidad, 2019. http://dx.doi.org/10.26754/c_agroing.2019.com.3453.
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