Sensitivity to the racemic mixture and isomeric forms of metalaxyl in Indian and European homothallic and heterothallic isolates of Peronospora parasitica in Brassica species

Vishunavat, Karuna; Nashaat, N. I.; Heran, A.; Kolte, S. J.

doi:10.1016/s0261-2194(98)00059-3

Cited by 20 publications

(7 citation statements)

References 8 publications

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“…Metalaxyl is a systemic, apoplastically-transported acylanilide fungicide used as a seed treatment, a banded or broadcast soil application, and a foliar spray, and it is effective against diseases caused by oomycetes and highly active against fungi of the order Peronosporales (Vishunavat et al, 1998). Because of its broad-spectrum activity, this compound was registered for use on a wide range of crops and in many countries and regions (Sukul and Spiteller, 2000).…”

Section: Introductionmentioning

confidence: 99%

Comparison of R‐metalaxyl and rac‐metalaxyl in acute, chronic, and sublethal effect on aquatic organisms: Daphnia magna, Scenedesmus quadricanda, and Danio rerio

Yao

Zhu

Duan

et al. 2008

Environmental Toxicology

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Chiral pesticides are used widely in the world, and at present, older racemic products are being replaced by enantiopure products because of accelerated development of asymmetry synthesis techniques. Pesticides as xenobiotic released into environment impose a great stress on nontarget organisms. Although it is a necessary procedure for pesticides to have a registration based on toxicological data from nontarget organism, until now ecological risk assessment about metalaxyl only depend on racemic products. Hence, we investigated the acute, chronic, and sublethal toxicity of R-metalaxy and rac-metalaxyl on aquatic organisms such as D. magna (Daphnia magna), algae (Scenedesmus quadricanda), and adult zebrafish (Danio rerio). The results showed a significant difference in toxicity between R-metalaxyl and rac-metalaxyl. R-Metalaxy was about 20-fold more toxic to algae than rac-metalaxyl with IC(50) of 222.89 +/- 1.18 mg/L and 19.95 +/- 1.12 mg/L, respectively. Similarly, R-metalaxyl was about fourfold toxic to D. magna than rac-metalaxyl according to the individual 24-h-LC(50) values, and sixfold toxic than rac-metalaxyl based on 24-h-EC(50) values. In the light of 48-h-LC(50) and EC(50), this difference in toxicity was more significant. As for adult zebrafish, there was no pronounced difference in acute toxicity, in addition, at sublethal level a different pattern in inducing Na(+),K(+)-ATPase activity between them was found. In general, R-metalaxyl seemed more toxic to aquatic organisms than rac-metalaxyl.

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Section: Introductionmentioning

confidence: 99%

Comparison of R‐metalaxyl and rac‐metalaxyl in acute, chronic, and sublethal effect on aquatic organisms: Daphnia magna, Scenedesmus quadricanda, and Danio rerio

Yao

Zhu

Duan

et al. 2008

Environmental Toxicology

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“…Peronospora parasitica reproduces sexually with both homothallic and heterothallic isolates (Sherriff & Lucas, 1989), and isolates with higher aggressiveness and virulence may occur (Gunn et al ., 1998) and compromise existing downy mildew‐resistant cultivars. The control of epidemics remains uncertain because isolates exist that are insensitive to both metalaxyl‐based compounds and Remiltine, a unique fungicide authorized in France, consisting of a mixture of cymoxanil and mancozeb (Vishunavat et al ., 1998; D.S. and co‐workers, unpublished results).…”

Section: Introductionmentioning

confidence: 99%

Production of pathogenesis‐related proteins in the cauliflower (Brassica oleracea var. botrytis)–downy mildew (Peronospora parasitica) pathosystem treated with acibenzolar‐S‐methyl

et al. 2001

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Bretagne Biotechnologie Ve Â ge Â tale, BBV, Penn-ar-prat, F-29250 Saint Pol-de-Le Âon, France Acibenzolar-S-methyl (ASM), a member of the benzothiadiazoles (BTH), was tested on cauliflower (Brassica oleracea var. botrytis) seedlings for its ability to induce resistance against downy mildew (Peronospora parasitica). Seven-dayold seedlings of the susceptible cultivar Billabong, sprayed with solutions containing 0´015 or 0´075 mg a.i. mL 21 ASM and inoculated 1±8 days later with P. parasitica, were assessed for disease 7 days after inoculation. Sporulation was reduced by 50% at the highest dose of ASM in plants inoculated 1 day later, with complete protection exhibited by plants inoculated 2 days after ASM treatment. Seedlings treated with 0´05 mg a.i. mL 21 ASM solution, inoculated 4 days later and harvested 0±7 days later, were analysed for pathogenesis-related (PR) proteins, chitinase and b-1,3 glucanase. ASM significantly induced b-1,3 glucanase activity which increased with time in inoculated seedlings, as confirmed by the presence of PR-2. Chitinase activity was not significantly induced by ASM, and the treated seedlings also did not accumulate the basic PR-3C and the acidic PR-3Q which both exhibit chitinase activity. Analysis of three other acidic (PR-1C, PR-5S, PR-8) and one basic (PR-6) PR proteins in the ASM-treated seedlings showed that only PR-1 and PR-5 were slightly and slowly induced (4±5 days after treatment), but this induction was more pronounced after inoculation with P. parasitica.

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“…However, they did not test mature plants of lines exhibiting seedling resistance. Peronospora parasitica isolates may be homothallic or heterothallic (Sherriff and Lucas 1989;Sequeira and Monteiro 1996;Vishunavat et al 1998) and recombination of pathogenicity attributes has been suggested among progeny from outcrosses of homothallic isolates (Gunn et al 1998). It is therefore possible that sexual recombination plays a role in increasing variation for pathogenicity.…”

Section: Field Testmentioning

confidence: 99%

Comparison of the resistance and susceptibility to downy mildew [Hyaloperonospora parasitica, constant. (Pers. Ex Fr)] of nine Brassica olearacea accessions in laboratory, seedbed, and field screens

Monot¹,

Silué²

2009

Euphytica

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The relationship between resistance in seedlings, young and adult plants is studied for the pathosystem Brassica oleracea-Hyaloperonospora parasitica. Genotypes identified in the laboratory as resistant or susceptible or exhibiting a differential reaction to a selection of H. parasitica isolates were tested in 1997-1999 in seedbeds and fields under natural infestation. Isolates tested in the laboratory were grouped in five pathotypes, of which four were presented by isolates from Brittany, France. Genotypes susceptible to all pathotypes in the laboratory were also susceptible in the seedbed and field tests, while genotypes expressing a differential response to pathotypes were either resistant or susceptible. Accessions Everest, DEGC, ESPG and RS1105 exhibiting resistance to all pathotypes except I, were resistant in all environments and remained resistant in 2000-2002. Pathotype I was not prevailing in the field and results support the hypothesis that accessions resistant under laboratory conditions will be resistant under field conditions, provided the same pathotypes are present under the laboratory and field conditions.

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Sensitivity to the racemic mixture and isomeric forms of metalaxyl in Indian and European homothallic and heterothallic isolates of Peronospora parasitica in Brassica species

Cited by 20 publications

References 8 publications

Comparison of R‐metalaxyl and rac‐metalaxyl in acute, chronic, and sublethal effect on aquatic organisms: Daphnia magna, Scenedesmus quadricanda, and Danio rerio

Comparison of R‐metalaxyl and rac‐metalaxyl in acute, chronic, and sublethal effect on aquatic organisms: Daphnia magna, Scenedesmus quadricanda, and Danio rerio

Production of pathogenesis‐related proteins in the cauliflower (Brassica oleracea var. botrytis)–downy mildew (Peronospora parasitica) pathosystem treated with acibenzolar‐S‐methyl

Comparison of the resistance and susceptibility to downy mildew [Hyaloperonospora parasitica, constant. (Pers. Ex Fr)] of nine Brassica olearacea accessions in laboratory, seedbed, and field screens

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