Host Range of <i>Phytophthora capsici</i> from Pumpkin and Pathogenicity of Isolates

Tian, Donglan; Babadoost, M.

doi:10.1094/pdis.2004.88.5.485

Cited by 85 publications

(40 citation statements)

References 15 publications

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“…The response of invasive plants to pathogen accumulation may vary widely based on pathogen virulence, abundance, and diversity (Holah and Alexander 1999, Tian and Babadoost 2004, Ghazvini and Tekauz 2008. Our results show a broad range of plant responses to the pathogens isolated from Microstegium with an almost fourfold difference in the lesion area per leaf between Bipolaris 1 and Curvularia (Fig.…”

Section: Discussionmentioning

confidence: 70%

Ecological consequences of pathogen accumulation on an invasive grass

Flory

Kleczewski²,

Clay

2011

Ecosphere

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Abstract. Release from natural enemies can contribute to the success of biological invasions. However, the advantage gained through enemy release may diminish over time as pathogens, parasites, or herbivores accumulate on invasive species. Pathogen accumulation may result from the development of novel host-pathogen interactions in the invasive range or the introduction of pathogens from the invader's home range or other areas. Previous studies suggest that pathogen accumulation may reduce the performance of invasive species but experimental demonstrations are lacking. Microstegium vimineum is a highly invasive annual grass with an expanding distribution in eastern North America. Bipolaris species and other fungal pathogens have recently been shown to cause foliar blight on invasive populations of Microstegium. Here we used experimental inoculations in controlled laboratory and greenhouse conditions and fungicide applications in the field to evaluate host relations of pathogens infecting invasive Microstegium and the ecological consequences of pathogen infection in nature. Four of seven native plant species tested, including three native grasses and one forb, became infected by at least one of the five pathogens isolated from Microstegium, suggesting that the native species might be sources or alternative hosts for Microstegium pathogens. Microstegium populations may also provide a reservoir of pathogens that could spillover to co-occurring native species and exacerbate the effects of invasions. All five pathogens caused foliar lesions on Microstegium, but there was over a four-fold difference in lesion area caused by different pathogens. Fungicide applications to infected field populations significantly reduced disease symptoms, increased invader biomass by up to 50% and increased seed head production by up to 200% compared to controls. Our results show that pathogen infection of invasive Microstegium caused significant declines in invasive host performance in natural populations, suggesting that the release of invasive species from natural enemies may be temporary.

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Section: Discussionmentioning

confidence: 70%

Ecological consequences of pathogen accumulation on an invasive grass

Flory

Kleczewski²,

Clay

2011

Ecosphere

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“…Phytophthora species cause disease in many different plant species (Birch et al 2006). P. capsici has a broad host range but isolates can show specificity (Tian and Babadoost 2004). For example, although some isolates of P. capsici cause disease on cacao, others cause a devastating disease on hot pepper (Capsicum annuum), causing severe yield losses (Kim and Hwang 1992).…”

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confidence: 99%

Endophytic Trichoderma Isolates from Tropical Environments Delay Disease Onset and Induce Resistance Against Phytophthora capsici in Hot Pepper Using Multiple Mechanisms

Bae¹,

Roberts²,

Lim³

et al. 2011

MPMI

197

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Endophytic Trichoderma isolates collected in tropical environments were evaluated for biocontrol activity against Phytophthora capsici in hot pepper (Capsicum annuum). Six isolates were tested for parasitic and antimicrobial activity against P. capsici and for endophytic and induced resistance capabilities in pepper. Isolates DIS 70a, DIS 219b, and DIS 376f were P. capsici parasites, while DIS 70a, DIS 259j, DIS 320c, and DIS 376f metabolites inhibited P. capsici. All six isolates colonized roots but were inefficient stem colonizers. DIS 259j, DIS 320c, and DIS 376f induced defense-related expressed sequence tags (EST) in 32-day-old peppers. DIS 70a, DIS 259j, and DIS 376f delayed disease development. Initial colonization of roots by DIS 259j or DIS 376f induced EST with potential to impact Trichoderma endophytic colonization and disease development, including multiple lipid transferase protein (LTP)-like family members. The timing and intensity of induction varied between isolates. Expression of CaLTP-N, encoding a LTP-like protein in pepper, in N. benthamiana leaves reduced disease development in response to P. nicotianae inoculation, suggesting LTP are functional components of resistance induced by Trichoderma species. Trichoderma isolates were endophytic on pepper roots in which, depending on the isolate, they delayed disease development by P. capsici and induced strong and divergent defense reactions.

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“…where X i is the disease incidence at the ith observation, t i is the number of days at the ith observation, and n is the total number of observations (Tian and Babadoost 2004). Sporangial heads from isolates 2256 and 2289 grown on CV8 plates at 25°C for 2 weeks were measured for length, width, and pedicel length, using a light microscope (Universal transmitted-light microscope; Carl Zeiss D-7082, Oberkochen, West Germany) at magnifications ranging from × 25 to × 40, with calibrated objectives.…”

Section: Methodsmentioning

confidence: 99%

First report ofPhytophthora capsicion cucurbits and peppers in British Columbia

Sholberg

Walker

O’Gorman

et al. 2007

Canadian Journal of Plant Pathology

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Phytophthora capsici is a devastating pathogen of several commercial cucurbit and solanaceous crops. In August 2004, P. capsici was isolated and identified for the first time in British Columbia from an infected pumpkin (Cucurbita pepo var. medullosa) purchased from a market garden in Kelowna. Visual symptoms of fruit rot were also evident on several varieties of squash (Cucurbita spp.), pepper (Capsicum annuum), and eggplant (Solanum melongena var. esculentum) from the same area. Further characterization of the causal agent was needed to confirm its identification, pathogenicity, and ability to overwinter. Eight isolates obtained from infected pumpkin and from five different squash varieties grew on selective media for P. capsici. Single-spore isolates were produced from these cultures, and DNA was extracted from them. On the basis of sequence analysis, the eight isolates were P. capsici, differing by two or fewer nucleotides in the ribosomal spacer (internal transcribed spacer 2 (ITS2)) regions compared with previously identified strains. In pathogenicity studies, isolates 2256 and 2289, originally from butternut squash (Cucurbita moschata) and pumpkin, respectively, infected sweet pepper (Capsicum annuum var. frutescens) and butternut squash, killing pepper plants in 8 days. The isolates were less pathogenic on squash, according to the area under the disease progress curve, which was approximately six times higher in pepper than squash. Phytophthora capsici was recovered from both sweet pepper and butternut squash, as well as from infected zucchini (Cucurbita pepo var. melopepo) and watermelon (Citrullus lanatus) plants. Mating studies showed that isolates 2256 and 2289 were probably the A1 mating type because they produced oospores only if they were paired with the A2 tester strain obtained from the Centraalbureau voor Schimmelcultures culture collection. A hypothesis on how the disease developed and spread in British Columbia is presented. 158Résumé : Le Phytophthora capsici est un agent pathogène qui ravage plusieurs cultures commerciales de cucurbitacées et de solanacées. En août 2004, le P. capsici a été isolé et identifié pour la première fois en Colombie-Britannique à partir d'une citrouille (Cucurbita pepo var. medullosa) infectée achetée dans un jardin maraîcher de Kelowna. Les symptômes visuels de pourriture des fruits étaient aussi facilement observables sur plusieurs variétés de courge (Cucurbita spp.), de piments (Capsicum annuum) et d'aubergine (Solanum melongena var. esculentum) de la même région. Une caractérisation plus poussée de l'agent responsable était nécessaire afin de confirmer son identité, sa pathogénicité et sa capacité à hiverner. Huit isolats provenant de citrouille et de cinq différentes variétés de courge infectées se sont développés sur un milieu sélectif pour le P. capsici. Des isolats monospores ont été produits à partir de ces cultures, et leur ADN a été extrait. Sur la base des analyses des séquences, les huit isolats correspondaient au P. capsici, avec une différence maxima...

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Host Range of Phytophthora capsici from Pumpkin and Pathogenicity of Isolates

Cited by 85 publications

References 15 publications

Ecological consequences of pathogen accumulation on an invasive grass

Ecological consequences of pathogen accumulation on an invasive grass

Endophytic Trichoderma Isolates from Tropical Environments Delay Disease Onset and Induce Resistance Against Phytophthora capsici in Hot Pepper Using Multiple Mechanisms

First report ofPhytophthora capsicion cucurbits and peppers in British Columbia

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