Genetics of Metalaxyl Resistance inPhytophthora infestans

Lee, Theresa Yun; Mizubuti, Eduardo S. G.; Fry, William E.

doi:10.1006/fgbi.1998.1107

Cited by 73 publications

(50 citation statements)

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“…Data supporting a significant reduction of fitness characteristics (Bruin and Edgington, 1982), or indicating stability of the resistant phenotype (Joseph and Coffey, 1984;Chabane et al, 1993) and/or pathogenicity of mutant isolates similar to the sensitive ones (Bruin and Edgington, 1982;Kadish et al, 1990;Chabane et al, 1993) have been reported. However, resistance to phenylamides was found to be under the control of a single gene in P. infestans, and correlation studies between resistance and fitness components did not reveal any association (Lee et al, 1999).…”

Section: Discussionmentioning

confidence: 98%

“…The selection of resistant mutants clearly indicates a dominance of resistant allele(s) in P. infestans. Studies on the genetic control of resistance to phenylamides have recognized a dominance of resistant alleles in P. infestans (Lee et al, 1999;Shattock, 2002). Studies on the sensitivity of mutant strains to fungicides from other chemical groups showed that the mutation(s) for resistance to IPV, BVC and CZF also greatly reduced the sensitivity of mutant isolates to the phenylamide metalaxyl, acetamide cymoxanil, morpholine dimethomorph, benzamide zoxamide and chlorothalonil.…”

Section: Discussionmentioning

confidence: 98%

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A High Multi-drug Resistance to Chemically Unrelated Oomycete Fungicides in Phytophthora infestans

et al. 2006

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Mutants of Phytophthora infestans with high resistance to the amidocarbamates iprovalicarb and benthiavalicarb and to the cyanoimidazole cyazofamid were isolated after UV-mutagenesis and selection on media containing one of the above fungicides. In vitro fungitoxicity tests showed that all resistant strains presented a highly reduced sensitivity to both cyazofamid and to the amidocarbamates. Cross-resistance studies with other oomycete fungicides from different chemical groups showed that the mutation(s) for resistance to iprovalicarb (IPV), benthiavalicarb (BVC) and cyazofamid (CZF) also greatly reduced the sensitivity of mutant strains to the phenylamide metalaxyl, acetamide cymoxanil, morpholine dimethomorph, benzamide zoxamide and to chlorothalonil. A lower reduction of sensitivity of mutant strains to the strobilurins azoxystrobin, kresoxim-methyl, pyraclostrobin and trifloxystrobin, azolones famoxadone and fenamidone and to antimycin A was observed. A resistance correlation was not apparent for the dithiocarbamate propineb and phenylpyridinamine fluazinam. Studies of fitness parameters in the wild-type and mutant strains of P. infestans showed that most resistant isolates had significantly reduced sporulation and sporangial germination, but not in the differentiation of sporangia into zoospores. Pathogenicity tests on tomato seedlings showed that most resistant isolates were significantly less pathogenic compared to the wild-type parent strain. However, experiments on the stability of the resistant phenotypes did not show a reduction in resistance when the mutants were grown for more than eleven generations on inhibitor-free medium. This is believed to be the first report of high level multi-drug resistance in fungal pathogens to chemically unrelated fungicides inhibiting different sites of cellular pathway.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 98%

A High Multi-drug Resistance to Chemically Unrelated Oomycete Fungicides in Phytophthora infestans

et al. 2006

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“…Until the 1980's, only a single clonal lineage of the A1 mating type was present outside Mexico or the Andes (Goodwin et al 1994), the centre of origin being still debated (Grunwald and Flier 2005;Gomez-Alpizar et al 2007), and after that the A2 mating type was introduced to both Europe and North America. This caused P. infestans to re-emerge as a very serious threat to potato cultivation by increasing its aggressiveness towards the host, reducing fungicide efficacy, facilitating its survival in soil or debris and broadening its host range to include tomato Fry and Goodwin 1997;Gavino et al 2000;Lee et al 1999). Because of the significant impact of this migration, P. infestans has become a model system for population genetics and the basis of international collaborations for population tracking (Cooke and Lees 2004;Goodwin et al 1992;Forbes et al 1998;Fry et al 1992).…”

Section: Oomycetes As Pathogensmentioning

confidence: 99%

Fifty years of oomycetes—from consolidation to evolutionary and genomic exploration

Lévesque

2011

Fungal Diversity

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Transformative changes in biological sciences during the past 25 years have led to many significant advances in oomycete research. Before the last half century there were some hints that the oomycetes were related to some algae but it is now definitively demonstrated that they do not share an evolutionary path with kingdom Eumycota and are instead placed in a new kingdom Straminipila. Clarifying this once and for all has created many opportunities, but the rapid expansion of the research community has caused some fragmentation, probably much more so than in other groups of fungi because of a lack of a unifying forum for the members of the community working on issues such as taxonomy or phylogeny. Prior to the advent of molecular phylogenetics, mycologists working in zoosporic fungi were examining the ultrastructure of the zoospore, mainly focussing on the flagellar apparatus, and managed to generate phylogenies or define clades of zoospore producing fungi that remained for the most part valid after the advances in molecular biology. Comprehensive molecular phylogenies that have been published for some genera of the oomycetes have helped in recognising a large number of new species and in the development of a wide range of DNA-based diagnostic tools. The number of genomes available for this group is increasing rapidly, pushing further the discoveries of novel host-parasite interaction mechanisms in oomycetes. Some important plant diseases that were believed to be under control have re-emerged and many new diseases have appeared particularly in forestry and even in mammals. The research community has been able to respond rapidly and effectively to these new challenges. New ecological roles for the oomycetes were found in the suppression of plant diseases and reduction of plant invasineness in natural ecosystems. There are still many challenges ahead in the oomycete community, probably the most pressing one is to establish a robust tree of life foundation like the Assembling the Fungal Tree of Life initiative. The oomycete research community is dynamic and has put to very good use the many new technological advances.

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“…As a consequence, there are currently only a few tomato and potato varieties that are moderately resistant to late blight. Metalaxyl resistance has been observed in Cameroon (Fontem et al, 2005) and elsewhere (Lee et al, 1999;Mukalazi et al, 2001). Other control measures such as cultural and physical methods have been found to be of low efficiency, high cost and difficult to implement in an Article published by EDP Sciences and available at http://www.agronomy-journal.org or http://dx.doi.org/10.1051/agro:2008036 extensive area, especially in developing countries (Schippers, 2004).…”

Section: Introductionmentioning

confidence: 99%

High efficacy of extracts of Cameroon plants against tomato late blight disease

Goufo

Mofor

Fontem

et al. 2008

Agron. Sustain. Dev.

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-The classical protection of tomato plants against the late blight disease caused by the fungi Phytophthora infestans involves the use of synthetic fungicides. However, such a practice raises two major issues. First, synthetic fungicides are toxic substances that are a threat to the ecosystem. Second, the efficiency of synthetic fungicides is decreasing due to the development of fungicide resistance by the fungi. In addition, there is growing concern from consumers about food contamination due to heavy reliance on toxic and persistent chemicals in plant protection strategies. Therefore, there is a necessity to evaluate the efficacy of alternative compounds. Biologically active products occur in plants for protection against pests, pathogens and other plants. Such compounds could be valuable as biopesticides for controlling plant diseases because they are biodegradable and selective in their activities. In that context, we conducted laboratory and greenhouse experiments to assess the efficacy of nine extracts of native plants of Cameroon in controlling P. infestans. Sporangial germination was determined after 24 h of incubation on 1.5% water agar medium at 18• C in the dark. Lesion size, and late blight latency and severity were assessed on 7-8-week-old detached leaflets and whole tomato plants incubated in the greenhouse for 7 days. Our results showed that Cupressus benthamii and Vetiveria zizanioides extracts were the most effective preparations, leading to 23% and 35% inhibition of sporangial germination, respectively, and to 86% and 77% disease reduction. A clear relationship between disease latency and disease severity was established. The identification of C. benthamii and V. zizanioides extracts as potential alternate compounds for late blight control is a major step in the process of replacing harmful pesticides. Using these biopesticides in combination with other established disease management practices could help control late blight in a more sustainable and environmentally friendly way. plant extracts / Phytophthora infestans / late blight / tomato / antifungal activity / disease suppression / biopesticide

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Genetics of Metalaxyl Resistance inPhytophthora infestans

Cited by 73 publications

References 46 publications

A High Multi-drug Resistance to Chemically Unrelated Oomycete Fungicides in Phytophthora infestans

A High Multi-drug Resistance to Chemically Unrelated Oomycete Fungicides in Phytophthora infestans

Fifty years of oomycetes—from consolidation to evolutionary and genomic exploration

High efficacy of extracts of Cameroon plants against tomato late blight disease

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