scholarly journals Sub-Specific Populations of Verticillium dahliae and their Roles in Vascular Wilt Pathogsystems

Author(s):  
Randall C. Rowe ◽  
Jaacov Katan ◽  
Talma Katan ◽  
Leah Tsror

Verticillium dahliae is an economically important pathogen causing vascular wilt on over 160 plant species. In North America, potato early dying is a significant disease of potato, especially in the midwest and Pacific northwest states. This disease is caused by the fungus Verticillium dahliae and in some cases involves a synergistic interaction with root-lesion nematodes, primarily Pratylenchus penetrans. In Israel, Verticillium wilt occurs in many regions and inflicts serious losses in potato, cotton, and other crops. Objectives of this project were to establish a large collection of isolates of Verticillium dahliae from potato (USA) and several host plants (Israel) and to characterize and compare the isolates with regard to morphology, vegetative compatibility group (VCG), and pathogenic capabilities on several hosts. Isolations were made from 224 commercial lots of certified potato seed tubers from across N. America and 87 potato fields located in the Columbia Basin of Oregon and Washington. A large collection of isolates from central U.S. states already existed. In Israel, 47 field sites were sampled and isolates of Verticillium dahliae were recovered from 13 host plant species and from soil. Potato isolates from N. America were tested for vegetative compatibility and all found to be in VCG 4 with about 2/3 in VCG 4A and the rest in VCG 4B. VCG 4A isolates were significantly more aggressive on potato than VCG 4B isolates and were more likely to interact synergistically with P. penetrans. The Israeli isolates fell into three vegetative compatibility groups. Nearly all (> 90%) VCG2B and VCG 4B isolates were recovered from the northern and southern parts of Israel, respectively, with some overlap in central areas. Several pathotypes were defined in cotton, using cotton and eggplant together as differentials. All VCG 2B isolates from cotton caused severe disease in cotton, while VCG 2A and VCG 4B isolates from several crops were much less aggressive to cotton. When Israeli isolates of VCGs 2A, 2B and 4B were inoculated to potato and tomato, VCG 4B isolates caused much more severe disease on potato and VCG 2A isolates caused much more severe disease in tomato. Differential patterns of pathogenicity and aggressiveness of these VCGs on potato and tomato were consistent regardless of the host plant of origin. Isolates of the same VCG resembled one another more than isolates from different VCGs based on colony and microsclerotial morphology, temperature responses and, partially, in pathogenicity. Vegetative compatibility grouping of V. dahliae in Israel appears closely associated with specific pathogenicity and other phenotypic traits. The absence of VCG 4A in Israel is significant. VCG patterns among Verficillium populations are useful to predict relatedness and pathogenic potential in both countries.  

Plant Disease ◽  
2000 ◽  
Vol 84 (11) ◽  
pp. 1241-1245 ◽  
Author(s):  
K. F. Dobinson ◽  
M. A. Harrington ◽  
M. Omer ◽  
R. C. Rowe

Forty isolates of Verticillium dahliae, collected from potato seed tubers and potato plants from various regions in North America and previously assigned to vegetative compatibility groups (VCGs) 4A or 4B, were characterized using molecular markers. The VCG 4A isolates were previously shown to be a highly virulent pathotype of potato and to interact synergistically with the root-lesion nematode Pratylenchus penetrans to cause potato early dying. All but one of the VCG 4A isolates characterized in this study lacked the subspecies-specific repetitive DNA sequence E18 and could be differentiated from the remaining isolates by restriction fragment length polymorphisms (RFLPs) in the nuclear rDNA and Trp1 loci. The E18 RFLP patterns of several VCG 4B isolates from Maine and New York were highly similar to those of VCG 4B isolates previously collected from potato and tomato fields in Ontario. The data presented here suggest that the molecular markers will be useful for the detection and classification of isolates of V. dahliae associated with potato early dying.


2000 ◽  
Vol 90 (5) ◽  
pp. 529-536 ◽  
Author(s):  
Nadia Korolev ◽  
Jaacov Katan ◽  
Talma Katan

A collection of 565 isolates of Verticillium dahliae, recovered between 1992 and 1997 from 13 host plant species and soil at 47 sites in Israel, was tested for vegetative compatibility using nitrate-nonutilizing (nit) mutants. Three vegetative compatibility groups (VCGs) were found and identified as VCG2A (28 isolates), VCG2B (158 isolates), and VCG4B (378 isolates) by using international reference strains. One isolate was heterokaryon self-incompatible. Of the VCG2B isolates, 92% were recovered from the northern part of Israel and 90% of VCG4B isolates were recovered from the south, with some overlap in the central region. Isolates of the minor group VCG2A were geographically scattered among the two major VCGs. Isolates of the same VCG resembled one another more than isolates from different VCGs based on colony and microsclerotial morphology, temperature responses, and, partially, pathogenicity. Different pathotypes were defined among 60 isolates tested, using cotton (cv. Acala SJ-2) and eggplant (cv. Black Beauty) as differentials. All isolates in VCG2A and 86% of the isolates in VCG4B, irrespective of their origin, induced weak to moderate symptoms on cotton and moderate to severe symptoms on eggplant and were similar to the previously described cotton nondefoliating patho-type. In contrast, all cotton isolates in VCG2B caused severe foliar symptoms, stunting, and often death, but little or no defoliation of inoculated cotton plants. These were defined as a cotton defoliating-like pathotype and induced only weak to moderate symptoms on eggplant. We concluded that vegetative compatibility grouping of V. dahliae in Israel is closely associated with specific pathogenicity and other phenotypic traits.


2014 ◽  
Vol 43 (2) ◽  
pp. 241-251 ◽  
Author(s):  
Mehmet Erhan Göre ◽  
Belgin Coşge Şenkal ◽  
Selma Kuru Berk ◽  
Hüseyin Onaran ◽  
Nedim Altin ◽  
...  

2019 ◽  
Author(s):  
Hesham A.Y. Gibriel ◽  
Jinling Li ◽  
Longfu Zhu ◽  
Michael F. Seidl ◽  
Bart P.H.J. Thomma

Originality and significance statementDuring host colonization, plant pathogens secrete molecules that enable host colonization, also known as effector proteins. Here, we show that strains of the fungal plant pathogen Verticillium dahliae that are able to infect the same host plant harbour highly divergent LS effector repertoires. Our study outlines the variability within LS effector gene repertoires of V. dahliae strains, which may allow the various strains to be competitive in the co-evolution with their hosts.SummaryEffectors are proteins secreted by pathogens to support colonization of host plants, often by deregulating host immunity. Effector genes are often localized within dynamic lineage-specific (LS) genomic regions, allowing rapid evolution of effector catalogues. Such localization permits pathogens to be competitive in the co-evolutionary arms races with their hosts. For a broad host-range pathogen such as Verticillium dahliae it is unclear to what extent single members of their total effector repertoires contribute to disease development on multiple hosts. Here, we determined the core and LS effector repertoires of a collection of V. dahliae strains, as well as the ability of these strains to infect a range of plant species comprising tomato, cotton, Nicotiana benthamiana, Arabidopsis, and sunflower to assess whether the presence of particular LS effectors correlates with the ability to infect particular plant species. Surprisingly, we found that V. dahliae strains that are able to infect the same host plant harbor highly divergent LS effector repertoires. Furthermore, we observed differential V. dahliae core effector gene expression between host plants. Our data suggest that different V. dahliae lineages utilise divergent effector catalogs to colonize the same host plant, suggesting considerable redundancy among the activities of effector catalogs between lineages.


2020 ◽  
Vol 33 (4) ◽  
pp. 565-568 ◽  
Author(s):  
Haiyuan Li ◽  
Jichen Dai ◽  
Jun Qin ◽  
Wenjing Shang ◽  
Jieyin Chen ◽  
...  

Verticillium dahliae is a widely distributed soilborne pathogen that causes vascular wilt in more than 200 plant species. Defoliating and nondefoliating symptoms caused by the disease that result in either the loss or retention of leaves in infected plants, respectively, in hosts such as cotton, olive, and okra, divide the causal agent into defoliating and nondefoliating pathotypes. Our goal in this current work was to generate genome resources for the defoliating strain XJ592 and the nondefoliating strain XJ511 of V. dahliae isolated from cotton in China.


Author(s):  
Marcin W. Zielonka ◽  
Tom W. Pope ◽  
Simon R. Leather

Abstract The carnation tortrix moth, Cacoecimorpha pronubana (Hübner, [1799]) (Lepidoptera: Tortricidae), is one of the most economically important insect species affecting the horticultural industry in the UK. The larvae consume foliage, flowers or fruits, and/or rolls leaves together with silken threads, negatively affecting the growth and/or aesthetics of the crop. In order to understand the polyphagous behaviour of this species within an ornamental crop habitat, we hypothesized that different host plant species affect its life history traits differently. This study investigated the effects of the host plant species on larval and pupal durations and sizes, and fecundity (the number of eggs and the number and size of egg clutches). At 20°C, 60% RH and a 16L:8D photoperiod larvae developed 10, 14, 20 and 36 days faster when reared on Christmas berry, Photinia (Rosaceae), than on cherry laurel, Prunus laurocerasus (Rosaceae), New Zealand broadleaf, Griselinia littoralis (Griseliniaceae), Mexican orange, Choisya ternata (Rutaceae), and firethorn, Pyracantha angustifolia (Rosaceae), respectively. Female pupae were 23.8 mg heavier than male pupae, and pupal weight was significantly correlated with the duration of larval development. The lowest and the highest mean numbers of eggs were produced by females reared on Pyracantha (41) and Photinia (202), respectively. Clutch size differed significantly among moths reared on different host plants, although the total number of eggs did not differ. This study showed that different ornamental host plants affect the development of C. pronubana differently. Improved understanding of the influence of host plant on the moth's life history parameters measured here will help in determining the economic impact that this species may have within the ornamental plant production environment, and may be used in developing more accurate crop protection methodologies within integrated pest management of this insect.


2020 ◽  
Vol 168 (12) ◽  
pp. 900-910
Author(s):  
Eduardo G. Virla ◽  
María B. Aguirre ◽  
Guido A. Van Nieuwenhove ◽  
Erica B. Luft Albarracin ◽  
Guillermo A. Logarzo

Mycoscience ◽  
1998 ◽  
Vol 39 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Hideyuki Nagao ◽  
Hiroaki Arai ◽  
Satoko Oshima ◽  
Masanori Koike ◽  
Tsutomu lijima

2008 ◽  
Vol 140 (2) ◽  
pp. 192-202 ◽  
Author(s):  
Gaylord A. Desurmont ◽  
Paul A. Weston

AbstractExperiments were conducted under laboratory conditions to determine the influence of the relative sizes of predator and prey, temperature, presence of refugia, size of the search area, and host-plant species on the predation performance of Podisus maculiventris (Say) nymphs against viburnum leaf beetle, Pyrrhalta viburni (Paykull), a new landscape pest in North America that feeds on the foliage of species of Viburnum L. (Caprifoliaceae). Predator handling time was positively correlated with body mass of the prey for all instars of P. maculiventris, but the rate of increase of handling time relative to prey mass decreased as predator age increased. Temperature was positively correlated with predation rates, but the presence of refugia did not have an impact on predation. The influence of host-plant species and size of the search area was tested on southern arrowwood (Viburnum dentatum L.) and American cranberrybush (Viburnum opulus L. var. americanum Aiton). There was a significant interaction between plant species and size of the search area, the species effect becoming significant as leaf surface area increased. In the case of southern arrowwood a negative correlation between size of the search area and predation rate was also detected. The identification of these factors adds valuable knowledge for using P. maculiventris as a biological-control agent against P. viburni.


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