Pathogenic and morphological variability of Plasmopara halstedii, the causal agent of downy mildew in sunflower

Kulkarni, Sneha; Hegde, Yashoda R.; Kota, Ramesh V.

doi:10.2298/hel0950085k

Cited by 7 publications

(5 citation statements)

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“…In 1991, the presence of race 730 was confirmed in that country (Lac'ok 2008). The most predominant single race in sunflower-growing Karnataka, Andhra Pradesh, and Maharashtra states of India appears to be race 100 (Kulkarni et al 2009).…”

Section: Physiological Racesmentioning

confidence: 99%

Diseases of Edible Oilseed Crops

Chattopadhyay¹,

Kolte²,

Waliyar³

2015

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AgriculturalSciences. He has more than 22 years of research experience in oilseed crop disease management and has significantly contributed in the areas of understanding the host-pathogen interactions, epi demiology, and integrated disease management in sunflower, safflower, sesame, peanut, and rape seed-mustard crops. He has published more than 70 peer-reviewed research papers and 4 books. Dr. Chattopadhyay has to his credit several academic awards and one patent. His significant research achievements include the development of Fusarium wilt-resistant genotypes in safflower, the iden tification of genotypes of Brassica juncea resistant to a mixture of isolates of Albugo candida, the development of a biocontrol agent formulation to reduce the use of fungicides in the management of major diseases of oilseeds (Brassica), and seed treatment (and foliar application) of aqueous bulb extract of Allium sativum for the management of major foliar diseases (Alternaria blight, white rust, powdery mildew, and Sclerotinia stem rot) of mustard. S.J. Kolte, professor of plant pathology (Retd.

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Section: Physiological Racesmentioning

confidence: 99%

Diseases of Edible Oilseed Crops

Chattopadhyay¹,

Kolte²,

Waliyar³

2015

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“…Few studies are available that address the variability of the morphology of different pathogen isolates from the same species on the same host. Kulkarni et al [30] found that the sporangiophores and also the sporangia of different isolates of Plasmopara halstedii varied significantly in their morphology when grown on the same host under controlled conditions. And Salati et al [31] showed that the size of the sporangiophores of different Pseudoperonospora cubensis isolates taken from the same host can vary significantly.…”

Section: Introductionmentioning

confidence: 99%

Which Morphological Characteristics Are Most Influenced by the Host Matrix in Downy Mildews? A Case Study in Pseudoperonospora cubensis

2012

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Before the advent of molecular phylogenetics, species concepts in the downy mildews, an economically important group of obligate biotrophic oomycete pathogens, have mostly been based upon host range and morphology. While molecular phylogenetic studies have confirmed a narrow host range for many downy mildew species, others, like Pseudoperonospora cubensis affect even different genera. Although often morphological differences were found for new, phylogenetically distinct species, uncertainty prevails regarding their host ranges, especially regarding related plants that have been reported as downy mildew hosts, but were not included in the phylogenetic studies. In these cases, the basis for deciding if the divergence in some morphological characters can be deemed sufficient for designation as separate species is uncertain, as observed morphological divergence could be due to different host matrices colonised. The broad host range of P. cubensis (ca. 60 host species) renders this pathogen an ideal model organism for the investigation of morphological variations in relation to the host matrix and to evaluate which characteristics are best indicators for conspecificity or distinctiveness. On the basis of twelve morphological characterisitcs and a set of twelve cucurbits from five different Cucurbitaceae tribes, including the two species, Cyclanthera pedata and Thladiantha dubia, hitherto not reported as hosts of P. cubensis, a significant influence of the host matrix on pathogen morphology was found. Given the high intraspecific variation of some characteristics, also their plasticity has to be taken into account. The implications for morphological species determination and the confidence limits of morphological characteristics are discussed. For species delimitations in Pseudoperonospora it is shown that the ratio of the height of the first ramification to the sporangiophore length, ratio of the longer to the shorter ultimate branchlet, and especially the length and width of sporangia, as well as, with some reservations, their ratio, are the most suitable characteristics for species delimitation.

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“…For zoosporangia sizes, the dimensions recorded as following: 30-33 µm to 36-57 µm in Nishimura (1922), 14-20 µm to 18-30 µm according to Hall (1989) and 12-16 µm to 27-40 µm in Spring et al (2003). Regarding sporangiophores sizes, Kulkarni et al (2009) reported that sporangiophores length varied from 325 to 700 µm and sporangiophores width ranged from 5 to 10 µm.…”

Section: Discussionmentioning

confidence: 99%

Phenotypical characterization in "Plasmopara halstedii" (sunflower downy mildew) isolates of several races

Sakr

2015

Bot. Complut.

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Phenotypic variation (morphological and pathogenic characters), and genetic variability were studied in 50 isolates of seven Plasmopara halstedii (sunflower downy mildew) races 100, 300, 304, 314, 710, 704 and 714. There were significant morphological, aggressiveness, and genetic differences for pathogen isolates. However, there was no relationship between morphology of zoosporangia and sporangiophores and pathogenic and genetic characteristics for the races used in our study. Also, our results provided evidence that no relation between pathogenic traits and multilocus haplotypes may be established in P. halstedii. The hypothesis explaining the absence of relationships among phenotypic and genetic characteristics is discussed.

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Pathogenic and morphological variability of Plasmopara halstedii, the causal agent of downy mildew in sunflower

Cited by 7 publications

References 0 publications

Diseases of Edible Oilseed Crops

Diseases of Edible Oilseed Crops

Which Morphological Characteristics Are Most Influenced by the Host Matrix in Downy Mildews? A Case Study in Pseudoperonospora cubensis

Phenotypical characterization in "Plasmopara halstedii" (sunflower downy mildew) isolates of several races

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