Prevalence of Xanthomonas euvesicatoria (formally X. perforans) associated with bacterial spot severity in Capsicum annuum crops in South Central Chihuahua, Mexico

Background Xanthomonas spp. causes bacterial spot disease, which reduces quality and yield of pepper crops in Mexico. Identification of phytopathogen species is necessary to implement more effective control strategies. Objective The aim of this study was to isolate and identify infecting Xanthomonas species in South Central Chihuahua pepper-producing areas. Methods Diseased plants were collected from 30 cultivation lots and bacteria were isolated from damaged tissues. Potential causative agents were isolated, identified, and characterized by biochemical and molecular analysis. Pathogenicity tests from each isolate were then performed on 30-d-old pepper seedlings, exposing five leaves to 10 µL of 1 × 108 CFU/mL bacterial suspensions of each isolate, using sterile distilled water as a control. Disease severity was determined after 10 d by calculating leaf damage percentage. Furthermore, we evaluated the susceptibility of the highest bacterial spot severity-causing isolates (13 isolates) to copper sulphate (CuS), copper gluconate (CuG), copper oxychloride + oxytetracycline hydrochloride (Cu + Ox), gentamicin + oxytetracycline hydrochloride (Gen + Ox), and gentamicin sulphate (GenS). Copper-resistance genes (copLAB) were detected by PCR analysis among isolates. Results Thirty-seven foliage isolates were identified as Xanthomonas euvesicatoria (14%), which were associated with bacterial spot disease in jalapeño pepper. Tested Xanthomonas isolates were resistant to Cu-based compounds, but susceptible to Cu + Ox. All isolates were susceptible to Gen + Ox and GenS. CopLAB genes were detected in all but one strain. Conclusions X. euvesicatoria (formally X. perforans) may be considered as an emerging pathogen of bacterial spot pepper in Mexico. Among disease management strategies, alternatives to copper should be taken into consideration.

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Occurrence of copper-resistant strains and a shift in Xanthomonas spp. causing tomato bacterial spot in Ontario

Canadian Journal of Microbiology ◽

10.1139/cjm-2015-0228 ◽

2015 ◽

Vol 61 (10) ◽

pp. 753-761 ◽

Cited By ~ 16

Author(s):

Pervaiz A. Abbasi ◽

Salah Eddin Khabbaz ◽

Brian Weselowski ◽

Liang Zhang

Keyword(s):

Species Composition ◽

Management Strategies ◽

Common Species ◽

Copper Resistance ◽

Pcr Analysis ◽

Bacterial Spot ◽

Cultivar Selection ◽

Fruit Samples ◽

Pathogenicity Tests ◽

Resistant Strains

Field strains of tomato bacterial spot pathogen (Xanthomonas euvesicatoria, X. vesicatoria, X. perforans, and X. gardneri) were characterized for sensitivity to copper and species composition. A total of 98 strains were isolated from symptomatic leaf and fruit samples collected from 18 tomato fields in Ontario. In greenhouse pathogenicity tests, most of the field strains caused severe (37 strains) to highly severe (23 strains) symptoms on ‘Bonny Best’ tomato plants, whereas 38 strains caused moderate symptoms. In MGY agar plates amended with various concentrations of copper sulfate, 11 strains were completely sensitive (no growth) and 87 strains were resistant (grew on 1.0 mmol/L or higher copper concentration). PCR analysis of the hrp gene cluster followed by restriction digestion with HaeIII and sequencing identified X. gardneri (35 strains) and X. perforans (26 strains) as predominant species and X. euvesicatoria and X. vesicatoria as less common species in Ontario tomato fields. Separation of field strains into various species was also confirmed with starch hydrolysis activity on agar medium. Moreover, 72 field strains produced shiny greenish-yellow colonies surrounded by a milky zone on xanthomonad differential (Xan-D) medium, and the colonies of 26 strains did not produce a milky zone. Thirty-four strains could not be clustered into any species and 25 of those strains were negative for the hrp gene PCR and also did not produce a milky zone around colonies on Xan-D medium. Our results suggest a widespread existence of copper-resistant strains and an increase in X. perforans strains of bacterial spot pathogen in Ontario. This information on copper resistance and species composition within bacterial spot pathogens in Ontario will be helpful for developing effective disease management strategies, making cultivar selection, and breeding new tomato cultivars.

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Xanthomonas euvesicatoria Causes Bacterial Spot Disease on Pepper Plant in Korea

The Plant Pathology Journal ◽

10.5423/ppj.oa.01.2016.0016 ◽

2016 ◽

Vol 32 (5) ◽

pp. 431-440 ◽

Cited By ~ 11

Author(s):

Min-Seong Kyeon ◽

Soo-Hyeong Son ◽

Young-Hee Noh ◽

Yong-Eon Kim ◽

Hyok-In Lee ◽

...

Keyword(s):

Pepper Plant ◽

Bacterial Spot ◽

Spot Disease ◽

Bacterial Spot Disease ◽

Xanthomonas Euvesicatoria

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Satureja montana Essential Oil, Zein Nanoparticles and Their Combination as a Biocontrol Strategy to Reduce Bacterial Spot Disease on Tomato Plants

Horticulturae ◽

10.3390/horticulturae7120584 ◽

2021 ◽

Vol 7 (12) ◽

pp. 584

Author(s):

Paulo R. Oliveira-Pinto ◽

Nuno Mariz-Ponte ◽

Rose Marie O. F. Sousa ◽

Ana Torres ◽

Fernando Tavares ◽

...

Keyword(s):

Antimicrobial Activity ◽

Essential Oil ◽

Management Strategies ◽

Field Studies ◽

Phenylpropanoid Pathway ◽

Copper Resistance ◽

Bacterial Spot ◽

Tomato Production ◽

Tomato Plants ◽

Bacterial Spot Disease

Tomato bacterial spot (Bs), caused by Xanthomonas spp., including X. euvesicatoria (Xeu) remains a major threat for tomato production. The emergence of copper resistance strains of Xeu calls urgently for eco-friendly phytosanitary treatments as sustainable green alternatives for disease control. Satureja spp. essential oil (EO) has antimicrobial activity against xanthomonads and combined with zein nanoparticles (ZNPs), might offer a viable option for field applications. This study aims to evaluate the effects of S. montana EO, of ZNPs, and their combination in a nanoformulation, on Xeu quantity, and how these compounds modulate molecular and physiological changes in the pathosystem. Uninfected and infected tomato plants (var. Oxheart) were treated with EO; ZNPs and nanoformulation (EO + ZNPs). Treatments reduced Xeu amount by a minimum of 1.6-fold (EO) and a maximum of 202-fold (ZNPs) and improved plants’ health. Nanoformulation and ZNPs increased plants’ phenolic content. ZNPs significantly increased GPX activity and reduced CAT activity. Overall treatments upregulated transcripts of the phenylpropanoid pathway in infected plants, while ZNPs and nanoformulation upregulated those transcripts in uninfected plants. Both sod and aao transcripts were downregulated by treatments in infected plants. These findings demonstrate that S. montana EO, ZNPs and their nanoformulation are suitable to integrate tomato bacterial spot management strategies, mainly due to their antimicrobial activity on Xeu, however further field studies clarifying the long-term action of these products are required. These results also support the prophylactic potential of ZNPs on tomato bacterial spot.

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