Uso de marcadores RAPD na classificação de isolados de Phytophthora spp. causadores da podridão parda do cacaueiro no Brasil

Faleiro, Fábio Gelape; Luz, Edna Dora Martins Newman; Cerqueira, A. O.; Rocha, Cenilda S.S

doi:10.1590/s0100-41582003000300015

Cited by 3 publications

(3 citation statements)

References 4 publications

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“…The knowledge of such interactions is essential, not only to understand the disease itself, but mainly to create control strategies aiming to interfere with its cycle (Bergamin & Amorim, 1996). The identification of phytopathogenic fungi is often based on morphological characteristics, but in many genera such characteristics are difficult to be observed in natural populations and are often affected by the environment (Faleiro et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Susceptibility of Clonal Seedlings of Eucalyptus spp. to Powdery Mildew Disease

et al. 2018

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Powdery mildew is one of the main diseases in eucalyptus clonal nursery. The present work aimed to confirm the identity of the causal agent of powdery mildew in clonal seedlings of Eucalyptus spp., and to evaluate the susceptibility reaction of clones to this disease. Conidia were collected in minigardens for molecular identification of the pathogen. We assessed susceptibility by testing 4 clones: Clone 1 (Eucalyptus benthamii), Clone 2 (E. dunni), Clone 3 (E. benthamii) and Clone 4 (E. urophylla x E. globulus). Scale of classes was used for calculations of Disease Index (DI) and Final Incidence (I). Temporal analysis was performed using the Logistic and Gompertz models. The molecular identification confirmed the identity of the isolates approximate to Podosphaera pannosa (teleomorphic phase of Oidium eucalypti). The Gompertz model obtained a better adjustment to the severity and incidence data, and clones 1 and 2 showed greater susceptibility to eucalyptus powdery mildew.

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Section: Introductionmentioning

confidence: 99%

Susceptibility of Clonal Seedlings of Eucalyptus spp. to Powdery Mildew Disease

et al. 2018

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“…The morphological characters, mainly the conidia ones, could be useful for species differentiation in Pestalotiopsis (Maharachchikumbura et al, 2011). However, in many genera, these characters are difficult to observe in natural populations and are often affected by environmental factors (Faleiro et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Identification and characterization of pathogenic Pestalotiopsis species to pecan tree in Brazil

Harakawa

Figueredo

2014

Pesq. agropec. bras.

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-The objective of this work was to characterize and cluster isolates of Pestalotiopsis species and to identify those that are pathogenic to pecan, based on morphological and molecular characters. Pestalotiopsis spp. isolates were identified by sequencing the internal transcribed spacer (ITS) and β-tubulin regions. Identification methods were compared to indicate the key morphological characters for species characterization. Thirteen isolates were used for the pathogenicity tests. Morphological characterization was performed using the following variables: mycelial growth rate, sporulation, colony pigmentation, and conidial length and width. Ten pathogenic isolates were identified, three as Pestalotiopsis clavispora and three as P. cocculi. The other isolates remained as an undefined species. The morphological characters were efficient for an initial separation of the isolates, which were grouped according to differences at species level, mainly colony diameter, which was identified as an important morphological describer. Beta-tubulin gene sequencing was less informative than the ITS region sequencing for species identification.Index terms: Carya illinoinensis, β-tubulin, ITS rDNA, morphological characters, phylogeny, UPGMA. Identificação e caracterização de espécies de Pestalotiopsis patogênicas à nogueira-pecã no BrasilResumo -O objetivo deste trabalho foi caracterizar e agrupar isolados de espécies de Pestalotiopsis e identificar aquelas patogênicas à nogueira-pecã, com base em caracteres morfológicos e moleculares. Os isolados de Pestalotiopsis spp. foram identificados por meio do sequenciamento das regiões internal transcribed spacer (ITS) e β-tubulina. Os métodos de identificação foram comparados, para indicar os caracteres morfológicos chave para a caracterização das espécies. Treze isolados foram utilizados para os testes de patogenicidade. A caracterização morfológica foi realizada com a utilização das seguintes variáveis: taxa de crescimento micelial, esporulação, pigmentação das colônias, comprimento e largura de conídios. Dez isolados patogênicos foram identificados, três como Pestalotiopsis clavispora e três como P. cocculi. Os outros isolados permaneceram como espécie não definida. Os caracteres morfológicos foram eficientes na separação inicial dos isolados, os quais foram agrupados por diferenças quanto à espécie, principalmente o diâmetro das colônias, identificado como um importante descritor morfológico. O sequenciamento do gene da β-tubulina foi menos informativo do que o sequenciamento da região ITS para a identificação de espécies.

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“…tropicalis , or P . hevea (Faleiro et al, 2003; Molina et al, 2016). This gives insights into the distribution of the Phytophthora spp.…”

Section: Discussionmentioning

confidence: 99%

Oomycete species associated with Theobroma cacao crops in Colombia

et al. 2021

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The study of oomycetes associated with crops is highly important due to the economic losses they might cause. In cacao, the genus Phytophthora has been extensively studied, but little is known about other genera and species of oomycetes associated with this plant. This study aimed to determine the oomycetes’ diversity present in Colombian cacao crops. A total of 146 isolates were obtained from diseased plants and soil in 11 departments. Analysis of internal transcribed spacer (ITS) and cytochrome oxidase subunit I (coxI) sequences was performed along with the assessment of morphological characteristics. Nine species were identified, distributed in four genera: Phytophthora (P. palmivora, 54%; P. nicotianae, 1%), Phytopythium (Phy. chamaehyphon, 15%; Phy. cucurbitacearum, 9%; Phy. vexans, 7%; Phy. helicoides, 1%), Globisporangium (G. splendens, 3%), and Pythium (Py. delicense, 1%; Py. inflatum,1%). Additionally, an unidentified and possibly new species of Phytophthora (5%) and three unidentified species of Phytopythium (3%) were found. This is the first report of Globisporangium, Phytopythium, and Pythium in cacao crops of Colombia and the first report of the species Phy. chamaehyphon in the country. Interestingly, some isolates of Phytopythium spp. were isolated from necrotic leaves and vascular section of stems, which may suggest a role in cacao diseases traditionally associated with Phytophthora. Also, it is proposed that the new species of Phytophthora may be contributing significantly to black pod disease in Colombian cacao crops, and we highlight that the study of P. palmivora is urgent because of its distribution all over the country.

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Uso de marcadores RAPD na classificação de isolados de Phytophthora spp. causadores da podridão parda do cacaueiro no Brasil

Cited by 3 publications

References 4 publications

Susceptibility of Clonal Seedlings of Eucalyptus spp. to Powdery Mildew Disease

Susceptibility of Clonal Seedlings of Eucalyptus spp. to Powdery Mildew Disease

Identification and characterization of pathogenic Pestalotiopsis species to pecan tree in Brazil

Oomycete species associated with Theobroma cacao crops in Colombia

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