Monitoring of a Single Point Mutation in the PvCesA3 Allele Conferring Resistance to Carboxylic Acid Amide Fungicides in Plasmopara viticola Populations In Yamanashi Prefecture, Japan

The use of the carboxylic acid amide (CAA) fungicide mandipropamid to manage grapevine downy mildew in vineyards in Japan has been increasing since 2010, because of widespread quinone outside inhibitor fungicide resistance in the Plasmopara viticola population. However, CAA fungicide resistance in P. viticola is becoming a serious problem worldwide. In 2013, we monitored for the presence of a single point mutation at codon 1105 of the cellulose synthase gene PvCesA3, which confers resistance to mandipropamid in P. viticola samples collected from four vineyards in Yamanashi prefecture in Japan. Five out of 157 samples were found to be heterozygotes, carrying both the mutated and nonmutated PvCesA3 alleles. Although CAA fungicide-resistant P. viticola isolates have not been reported yet in Japan, the emergence of heterozygous P. viticola populations indicates the potential risk of emergence of resistant homozygotes. Accepted for publication 14 March 2015. Published 1 May 2015

Download Full-text

A single point mutation in the novel PvCesA3 gene confers resistance to the carboxylic acid amide fungicide mandipropamid in Plasmopara viticola

Fungal Genetics and Biology ◽

10.1016/j.fgb.2010.02.009 ◽

2010 ◽

Vol 47 (6) ◽

pp. 499-510 ◽

Cited By ~ 58

Author(s):

Mathias Blum ◽

Maya Waldner ◽

Ulrich Gisi

Keyword(s):

Carboxylic Acid ◽

Point Mutation ◽

Single Point ◽

Acid Amide ◽

Plasmopara Viticola ◽

Single Point Mutation ◽

The Novel ◽

Carboxylic Acid Amide

Download Full-text

First Report of Carboxylic Acid Amide Fungicide Resistance in Plasmopara viticola (Grapevine Downy Mildew) in North America

Plant Health Progress ◽

10.1094/php-01-18-0005-br ◽

2018 ◽

Vol 19 (2) ◽

pp. 139-139 ◽

Cited By ~ 1

Author(s):

Xuewen Feng ◽

Anton Baudoin

Keyword(s):

North Carolina ◽

Carboxylic Acid ◽

North America ◽

Downy Mildew ◽

Acid Amide ◽

Plasmopara Viticola ◽

Carboxylic Acid Amide ◽

Grapevine Downy Mildew ◽

Grape Downy Mildew ◽

Caa Fungicides

This report documents the first known occurrence in North America of resistance in grape downy mildew (Plasmopara viticola) to the carboxylic acid amide (CAA) fungicides mandipropamid and dimethomorph. These fungicides (FRAC group 40) have been an important component of downy mildew management programs for the past decade. Resistant isolates were obtained at three locations in Virginia and one in North Carolina, at considerable distances from each other. Resistance was documented by bioassay and the presence of the G1105S mutation, which has been associated with CAA resistance of P. viticola in other areas. Further survey is needed to determine the geographic extent of this resistance.

Download Full-text

Detection and Characterization of Carboxylic Acid Amide-Resistant Plasmopara viticola in China Using a TaqMan-MGB Real-Time PCR

Plant Disease ◽

10.1094/pdis-02-20-0291-re ◽

2020 ◽

Vol 104 (9) ◽

pp. 2338-2345

Author(s):

Xiaoqing Huang ◽

Xina Wang ◽

Fanfang Kong ◽

Theo van der Lee ◽

Zhongyue Wang ◽

...

Keyword(s):

Carboxylic Acid ◽

Real Time ◽

Downy Mildew ◽

Real Time Pcr ◽

Fungicide Resistance ◽

Management Strategies ◽

Acid Amide ◽

Plasmopara Viticola ◽

Carboxylic Acid Amide ◽

Caa Fungicides

Grape production is increasing globally and so are problems with downy mildew, one of the main constraints in grape production. Downy mildew on grape is caused by Plasmopara viticola, an obligate biotrophic pathogen belonging to the oomycetes. Control of the disease is usually performed by fungicide applications, of which carboxylic acid amide (CAA) fungicides represent one of the most widely used groups of fungicides. Our previous research showed that the extensive application of CAA fungicides can result in fungicide resistance and in China, CAA-resistant isolates of P. viticola were collected from the field in 2014. To monitor the distribution and spread of CAA fungicide resistance, we developed a TaqMan-minor groove binder (MGB) real-time PCR-based method designed on a functional mutation in the PvCesA3 gene that allows efficient identification of CAA fungicide resistant and sensitive genotypes. The assay was validated on 50 isolates using Sanger sequencing and fungicide bioassays and exploited in a comprehensive survey comprising 2,227 single-sporangiophore isolates from eight major grapevine regions in China. We demonstrate that CAA fungicide resistance in P. viticola is widespread in China. On average, 53.3% of the isolates were found to be resistant, but marked differences were found between locations with percentages of resistant isolates varying from 0.3 to 96.6%. Furthermore, the frequency of CAA-resistant isolates was found to be significantly correlated with the exposure to CAA fungicides (P < 0.05). We further discussed the possibilities to apply the TaqMan-MGB real-time PCR assay to assess the frequency of fungicide-resistant P. viticola isolates in each region or vineyard, which would facilitate the correct choice of fungicide for grape downy mildew and resistance management strategies.

Download Full-text

Inheritance of resistance to carboxylic acid amide (CAA) fungicides in Plasmopara viticola

Plant Pathology ◽

10.1111/j.1365-3059.2006.01512.x ◽

2007 ◽

Vol 56 (2) ◽

pp. 199-208 ◽

Cited By ~ 69

Author(s):

U. Gisi ◽

M. Waldner ◽

N. Kraus ◽

P. H. Dubuis ◽

H. Sierotzki

Keyword(s):

Carboxylic Acid ◽

Acid Amide ◽

Plasmopara Viticola ◽

Inheritance Of Resistance ◽

Carboxylic Acid Amide ◽

Caa Fungicides

Download Full-text

Assessing the Risk That Phytophthora melonis Can Develop a Point Mutation (V1109L) in CesA3 Conferring Resistance to Carboxylic Acid Amide Fungicides

PLoS ONE ◽

10.1371/journal.pone.0042069 ◽

2012 ◽

Vol 7 (7) ◽

pp. e42069 ◽

Cited By ~ 9

Author(s):

Lei Chen ◽

Shusheng Zhu ◽

Xiaohong Lu ◽

Zhili Pang ◽

Meng Cai ◽

...

Keyword(s):

Carboxylic Acid ◽

Point Mutation ◽

Acid Amide ◽

Carboxylic Acid Amide ◽

Phytophthora Melonis

Download Full-text

Cercospora nicotianae Isolates from Flue-Cured Tobacco in North Carolina Found with G143A and F129L Mutations in Cytochrome b Gene

Plant Health Progress ◽

10.1094/php-04-20-0029-rs ◽

2020 ◽

Vol 21 (4) ◽

pp. 288-290

Author(s):

Andrew Ernst ◽

Lindsey Thiessen

Keyword(s):

North Carolina ◽

Leaf Spot ◽

Fungicide Resistance ◽

Single Point ◽

Leaf Spot Disease ◽

Single Point Mutation ◽

Resistance Mutations ◽

Quinone Outside Inhibitor ◽

Frogeye Leaf Spot ◽

Qoi Resistance

Frogeye leaf spot of tobacco caused by Cercospora nicotianae (Ellis & Everhart) is a widespread disease of cultivated tobacco. Recently, flue-cured tobacco producers in North Carolina reported losses due to frogeye leaf spot disease despite the use of strobilurin fungicides. Isolates (n = 4) were obtained in 2018 from affected tobacco leaves from Cumberland, Lenoir, and Nash counties. In 2019, isolates (n = 28) were collected from a field in Wilson county. After sequencing the cytb region of 32 isolates, 30 contained a single point mutation conferring a G143A or F129L amino acid change that resulted in quinone outside inhibitor (QoI) fungicide resistance. Although these resistance mutations have been found in air-cured tobacco in Kentucky, to the best of our knowledge, the present study is the first to report QoI resistance mutations in C. nicotianae populations in flue-cured tobacco and a first report in North Carolina.

Download Full-text

Emergence of Single Point Mutation in PvCesA3, Conferring Resistance to CAA Fungicides, in Plasmopara viticola Populations in Japan

Plant Health Progress ◽

10.1094/php-2013-0729-01-br ◽

2013 ◽

Vol 14 (1) ◽

pp. 51 ◽

Cited By ~ 1

Author(s):

Yoshinao Aoki ◽

Maki Hashimoto ◽

Shunji Suzuki

Keyword(s):

Point Mutation ◽

Single Point ◽

Plasmopara Viticola ◽

Single Point Mutation ◽

Caa Fungicides ◽

Near Future

As far as we know, there is no report of fungicide-resistant Plasmopara viticola in Japan. In the present study, we detected a single point mutation in the PvCesA3 of P. viticola sampled from a Japanese vineyard, which conferred resistance to mandipropamid. The emergence of the mandipropamid-resistant PvCesA3 allele may lead to the spread of mandipropamid-resistant P. viticola in vineyards all over Japan in the near future. Accepted for publication 23 April 2012. Published 29 July 2013.

Download Full-text

Fungicide Sensitivity Survey of Plasmopara viticola Populations in Georgia Vineyards

Plant Health Progress ◽

10.1094/php-05-20-0039-rs ◽

2020 ◽

Vol 21 (4) ◽

pp. 256-261

Author(s):

Sarah E. Campbell ◽

Phillip M. Brannen ◽

Harald Scherm ◽

Marin T. Brewer

Keyword(s):

Downy Mildew ◽

Acid Amide ◽

Leaf Disc ◽

Plasmopara Viticola ◽

Survey Period ◽

Resistance Development ◽

Grapevine Downy Mildew ◽

Quinone Outside Inhibitor ◽

History Of ◽

Qoi Resistance

Grapevine downy mildew, caused by Plasmopara viticola, is among the most damaging diseases of grapes globally and in the viticultural regions of Georgia (U.S.A.). Although management of this disease typically involves fungicide applications, resistance development in P. viticola can render chemical management ineffective. The objective of this study was to survey fungicide sensitivities of P. viticola populations in vineyards across three regions in Georgia. Samples were collected from eight vineyards in 2017 and four in 2018 and tested phenotypically for sensitivity to quinone outside inhibitor (QoI), carboxylic acid amide (CAA), and phenylamide (PA) fungicides using leaf disc bioassays. In addition, DNA was extracted from P. viticola samples collected from 2015 through 2018 in these 12 vineyards and six others for a total of 18 vineyards sampled. All available DNA samples were tested for the presence of the known resistance-causing mutations G143A (QoI) and G1105S (CAA) using polymerase chain reaction (PCR). This study documented widespread occurrence of QoI resistance in P. viticola in Georgia, with 83.0% of isolates collected in 2017 and 2018 testing positive for QoI resistance based on bioassay and 82.9% of isolates collected from 2015 to 2018 testing positive for QoI resistance through PCR testing. In total, 94.4% (17/18) of surveyed vineyards had confirmed QoI resistance by the conclusion of the survey period. No reduced sensitivity to CAA or PA fungicides was identified. Due to widespread QoI resistance, these fungicides should not be relied upon for downy mildew management in Georgia vineyards with a long history of their use.

Download Full-text