Genetic variation among pathogens causing "Helminthosporium" diseases of rice, maize and wheat

Weikert-Oliveira, Rita C. B.; Resende, Maria Aparecida de; Valério, Henrique Maia; Caligiorne, Rachel Basques; Paiva, Edílson

doi:10.1590/s0100-41582002000600015

Cited by 15 publications

(11 citation statements)

References 8 publications

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“…That is, most genotypes were unique and without predominance of any MLG within those populations. This high genetic diversity is in agreement with previous reports for other B. oryzae populations collected in Brazil, Bangladesh, India, the United States and the Philippines characterized by different molecular markers (Weikert‐Oliveira et al ., ; Kamal & Mia, ; Kumar et al ., ; Castell‐Miller & Samac, ; Burgos et al ., ).…”

Section: Discussionmentioning

confidence: 99%

Population structure, genetic diversity, and sexual state of the rice brown spot pathogen Bipolaris oryzae from three Asian countries

et al. 2017

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Bipolaris oryzae causes brown spot in rice (Oryza sativa) inflicting substantial grain yield losses worldwide. Knowledge of the population structure, genetic diversity and sexual recombination of the fungal pathogen can help to implement effective disease management strategies. In this study, B. oryzae isolates sampled from Iran, the Philippines and Japan were analysed with 12 simple-sequence repeat (SSR) markers, newly developed from the genome sequence of the fungus. Among the 288 B. oryzae isolates genotyped, 278 unique haplotypes were identified. High genotype numbers (richness) with even distribution (evenness) were found within the collection sites. Both mating types, MAT1-1 and MAT1-2, were present in each collection area, and the sexual state was induced under controlled conditions with production of viable ascospores. However, the tests of linkage disequilibrium rejected of the hypothesis of random mating. Discriminant analysis of principal components (DAPC) revealed that the B. oryzae collection formed three clusters, each consisting of isolates from different collection sites. Analysis of molecular variance (AMOVA) showed that genetic variation among clusters was 18.7%, with the rest of the variation distributed within clusters (R ST = 0.187, P < 0.001). Statistically significant pairwise genetic differentiation was found between the clusters. These results show that Asian B. oryzae isolates are genetically diverse, and, overall, distributed in three groups. These findings will be helpful in managing the disease and guide the use of representative isolates needed for selection of resistant rice varieties.

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Section: Discussionmentioning

confidence: 99%

Population structure, genetic diversity, and sexual state of the rice brown spot pathogen Bipolaris oryzae from three Asian countries

et al. 2017

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“…Hyphae and conidia of fungi in the genus Bipolaris feature dark coloration due to the presence of melanin in the cell wall (Weikert-Oliveira et al, 2002). In microorganisms, the primary function of this pigment is to reduce the harmful effects of UV radiation on the cells.…”

Section: Resultsmentioning

confidence: 99%

Selection of anti-wetting agents and photoprotectants compatible with a soybean weed control bioagent

Machado¹,

Monteiro²,

Mochi³

2016

Afr. J. Microbiol. Res.

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Adjuvants incorporation at formulations can positively influence the performance of bioagent control, contributing to preservation of the inoculum until being used. Adjuvants should not be toxic to pathogen and tests that evaluate the sensitivity of biologic products are essential. The aim of this study was to analyze the compatibility of the anti-wetting agents microcrystalline cellulose, anhydrous sodium carbonate, magnesium oxide, talc, calcium carbonate, silicon dioxide, and photoprotectants NeoHeliopan ® AV, NeoHeliopan ® E1000, Eusolex ® 6007, NeoHeliopan ® Hydro, Tinosorb ® M, Eusolex ® 232 and a Complex filters UVA/UVB with the fungus Bipolaris euphorbiae, in order to select products to formulate a fungus-based bioherbicide. All products were used in concentrations of 0.01, 0.05, 0.1, 0.5 and 1%. After evaluating vegetative growth, sporulation, and germination, the products were toxicologically classified by calculating the biological index. The anti-wetting agents calcium carbonate, talc, microcrystalline cellulose, and silicium dioxide did not interfere in the development of the fungus, and were deemed compatible. The photoprotectant Tinosorb ® M was classified as compatible with the fungus in all concentrations used, a similar outcome to Eusolex ® 6007, except at 1.0% concentration. Most of the other photoprotectants were compatible in concentrations ranging between 0.01 and 0.1%, except for Complex filters UVA/UVB at 0.05% and NeoHeliopan ® E1000 at 0.1%. NeoHeliopan ® Hydro was rated moderately toxic to the fungus in all concentrations used. Conidial germination was less affected than growth and sporulation.

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“…Some researchers do not acknowledge Bipolaris and Exserohilum as genera, but recognize the genus Drechslera and include the two genera Bipolaris and Exserohilum under the genus Helminthosporium. This classification is based on differences of conidial morphology and for some researchers these characteristics do not justify genera or species partition (Zhang and Berbee 2001; Weikert- Oliveira et al 2002). Zhang and Berbee (2001) sequenced the ITS regions and the codifying genes of glyceraldehyde-3-phosphate dehydrogenase sequences from different Bipolaris, Exserohilum, and Drechslera species.…”

Section: Pcr-rflp On Its1 and Its2 Regionsmentioning

confidence: 99%

Restriction analysis of the amplified ribosomal DNA spacers ITS1 and ITS2 of Bipolaris sorokiniana isolates

Nascimento

Sand

2007

World J Microbiol Biotechnol

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The purpose of this study was to examine the genotypic variability of Bipolaris sorokiniana by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis using rDNA. Fifty B. sorokiniana isolates from Brazil and other countries, one Bipolaris oryzae and six Drechslera teres isolates were used. The intragenic spacer regions (ITS1 and ITS2) were the regions used for characterization of isolates. The amplification products for both ITS regions, showed two DNA fragments for all isolates. Two B. sorokiniana isolates presented an intraspecific variability showing a third fragment for the ITS1 region. The dendrograms generated with PCR-RFLP data showed intra-and inter-specific groups. The dendrograms showed that most of Brazilian isolates clustered together forming groups between them, and this behavior was repeated with most isolates from other countries. The dendrograms did not enable the separation of B. sorokiniana isolates by their geographic origin or host type. These results suggest the occurrence of gene flow between different populations of the fungus isolated in geographically distant regions and lends cogency to the occurrence of gene flow between species.

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Genetic variation among pathogens causing "Helminthosporium" diseases of rice, maize and wheat

Cited by 15 publications

References 8 publications

Population structure, genetic diversity, and sexual state of the rice brown spot pathogen Bipolaris oryzae from three Asian countries

Population structure, genetic diversity, and sexual state of the rice brown spot pathogen Bipolaris oryzae from three Asian countries

Selection of anti-wetting agents and photoprotectants compatible with a soybean weed control bioagent

Restriction analysis of the amplified ribosomal DNA spacers ITS1 and ITS2 of Bipolaris sorokiniana isolates

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