Papers by Acelino Alfenas
Australasian Plant Pathology, 2007
Molecular Ecology Resources, Jun 28, 2008
Foliolos jovens e maduros, estes ultimos previamente feridos, destacados dos clones Fx 3864 e Fx ... more Foliolos jovens e maduros, estes ultimos previamente feridos, destacados dos clones Fx 3864 e Fx 2261 de seringueira, foram inoculados na face abaxial, com discos de papel de filtros embebidos em suspensoes de 3x10, 4x10, 5x10, 1x10, 1,5x10 e 2x10 zoosporos de Phytophthora capsici/ml. Em outra etapa desde trabalho, foliolos jovens e maduros foram inoculados com 2x10 zoosporos de P. capsici ou P. palmivora MF1/ml e mantidos em incubadoras com diferentes temperaturas (16, 20, 24 e 28C). Houve aumento da severidade da doenca com o aumento da concentracao de inoculo, observando-se maiores lesoes com 2x10 zoosporos/ml. A temperatura influenciou a infeccao por P. capsici e P. palmivora MF1 em foliolos jovens e maduros de seringueira. Observaram-se maiores periodos de incubacao (PI) e do periodo latente (PL) e maiores tamanho de lesao (TL) e esporulacao nos foliolos mantidos a 24 e 28C. Os mais longos PI e PL foram observados a 16C, quando a colonizacao pelo patogeno foi lenta e a esporulacao baixa. Em geral, P. capsici foi mais virulento que P. palmivora MF1.
Procederam-se estudos visando o desenvolvimento de metodologia para avaliacao de resistencia da s... more Procederam-se estudos visando o desenvolvimento de metodologia para avaliacao de resistencia da seringueira a Phytophthora capsici. O uso de foliolos jovens e maduros destacados, estes ultimos previamente feridos, foi adequado ao proposito previsto, pois os sintomas desenvolveram-se semelhantemente aos nos foliolos presos as plantas. Os foliolos nao inoculados mantiveram-se viaveis durante o periodo de execucao dos ensaios. Independentemente da idade dos foliolos e do clone, o periodo de incubacao latente e o tamanho das lesoes em foliolos destacados foram similares aos observados nos foliolos presos as plantas. No entanto, a producao de esporangios foi maior nos foliolos destacados.
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Fitopatologia Brasileira, 1995
Pest Management Science, Sep 13, 2018
Forest Pathology, Aug 19, 2017
Summary Ralstonia solanacearum is currently one of the most important plant pathogenic bacteria w... more Summary Ralstonia solanacearum is currently one of the most important plant pathogenic bacteria worldwide, with a wide geographical distribution and host diversity. The pathogen infects more than 200 plant species belonging to approximately 50 plant families, including Eucalyptus spp. Although, high losses have been reported in nurseries, little is known on the negative impact of the disease in the field. In this study, we evaluated the incidence of R. solanacearum and its effect on volumetric growth and cellulose yield of discoloured wood chips obtained from infected trees of one clone of Eucalyptus urophylla and two hybrid clones of Eucalyptus urophylla × E. grandis. The average incidence of bacterial wilt ranged between 60.6% and 72.4%. Volumetric growth of infected trees disease decreased 78.6% and 81.7% at 18 and 30 months, respectively. The pulp screen yield of three clones decreased between 3.2 and 6.4%, with an average 4.3%. The results of this work provide useful information on the losses of volumetric growth and pulp yield of eucalypt caused by R. solanacearum.
Plant Pathology, May 2, 2017
Ceratocystis fimbriata is native to Brazil, where it is able to cause serious diseases on numerou... more Ceratocystis fimbriata is native to Brazil, where it is able to cause serious diseases on numerous hosts, especially on non‐native plants. Because C. fimbriata is soilborne and not wind dispersed, highly differentiated populations are found in different regions of Brazil. The present study compared populations of C. fimbriata on taro, mango, eucalyptus and kiwifruit from the coastal Mata Atlântica region with native populations of the fungus from the Cerrado‐transition region in Brazil by using 14 SSR markers and DNA sequences of ITS and mating type genes. Microsatellite and phylogenetic analyses were performed to test the hypothesis that populations on different hosts from the Mata Atlântica region are related to each other and are native to the region. The ITS sequences varied greatly among the taro isolates, with six sequences identified, from which two had not been previously reported. For mating type genes, four sequences were identified among the isolates on taro, mango, eucalyptus and kiwifruit. Phylogenetic analyses showed that Mata Atlântica populations formed a monophyletic group distinct from Cerrado‐transition region populations, although earlier studies had shown that isolates from the two regions are interfertile and are considered as a single biological species. Microsatellite analysis revealed low gene diversity for each of the three Mata Atlântica populations on taro, mango and kiwifruit, suggesting that these populations had gone through genetic bottlenecks, probably by dispersal of select genotypes in vegetative propagation material. Also, microsatellite markers showed that two microsatellite genotypes from taro are widely spread in Brazil, probably by infected corms.
Plant Physiology and Biochemistry, Feb 1, 2018
Fitopatologia Brasileira, 2001
Forest Pathology, Oct 28, 2015
Summary Calonectria leaf blight (CLB), caused by Calonectria pteridis, is a major foliar disease ... more Summary Calonectria leaf blight (CLB), caused by Calonectria pteridis, is a major foliar disease of eucalypt plantations in warm and high rainfall regions in Brazil. The use of resistant genotypes is the best method for disease control in the field, so identification of sources of resistance is strategic for the long-term genetic breeding programmes of eucalypt. In this study, resistance of 13 species of Eucalyptus and 3 species of Corymbia to CLB was evaluated by spray inoculation of a spore suspension (1 × 104 conidia ml−1) of the pathogen, under controlled conditions. Eucalyptus brassiana, E. saligna, E. scias and E. agglomerata were the most resistant, while E. robusta, E. urophylla, E. camaldulensis, E. longirostrata and C. toreliana were moderately resistant and E. cloeziana, E. pellita, E. tereticornis, E. pilularis, C. maculata, E. grandis, E. dunnii and C. citriodora were the most susceptible. The broad inter and intraspecific variability of the species tested demonstrates the potential for introgression of resistance genes into valuable genotypes as a strategy for the breeding programmes and commercial plantation of eucalypt.
Plant Pathology, 2020
Kiwifruit (Actinidia spp.) is native to southern China, but was first cultivated in New Zealand a... more Kiwifruit (Actinidia spp.) is native to southern China, but was first cultivated in New Zealand and then spread worldwide. Emerging diseases such as ceratocystis wilt have attracted the attention of kiwifruit growers due to the great losses observed in southern Brazil. Effective control can be achieved by screening for resistance, but the genetic variability of the pathogen must be considered. Thus, this study aimed to assess the genetic diversity and variation in aggressiveness of Ceratocystis isolates from kiwifruit in southern Brazil and then evaluate the resistance of kiwifruit cultivars with the most aggressive isolates. A collection of 46 isolates were obtained from southern Brazil and 14 simple‐sequence repeat (SSR) markers was successfully used for genotyping. Out of 14 markers, 13 were polymorphic and identified 26 genotypes. Fourteen distinct genotypes were tested on a susceptible cultivar to select the most aggressive ones. Finally, inoculation with an equal mixture of fi...
Forest Pathology, 2019
Podosphaera pannosa is the causal agent of powdery mildew on eucalypt in Brazil. This powdery mil... more Podosphaera pannosa is the causal agent of powdery mildew on eucalypt in Brazil. This powdery mildew disease is important in nurseries causing leaf and shoot distortion, shoot discoloration and reduction in growth, which decreases mini‐cutting production. Improved RNA sequencing (RNA‐Seq) technologies have allowed increased information about the transcriptome of several pathogens and hosts, enabling a better understanding of their interaction at the gene level. For this study, we analysed the transcriptome of P. pannosa during leaf infection of Eucalyptus urophylla leaves using RNA‐Seq and de novo transcriptome assembly. The transcriptome was Illumina sequenced and assembled de novo, generating over 178 million RNA‐Seq reads assembled onto 200,473 contigs. After filtering steps, the resulting 12,106 (6%) transcripts were identified as the P. pannosa transcriptome data set. The 10 most abundant transcripts included genes encoding enzymes likely involved in fungal establishment and gr...
Pest management science, Jan 3, 2018
The response to infection of Austropuccinia psidii in a resistant (CLR-383) and susceptible (CLR-... more The response to infection of Austropuccinia psidii in a resistant (CLR-383) and susceptible (CLR-384) Eucalyptus grandis clones, exposed to herbicide drift of carfentrazone-ethyl, glyphosate and a mixture of these two herbicides, was evaluated at microscopic and physiological levels. Plants of the two clones showed symptoms of phytotoxicity caused by herbicide drift. However, net CO assimilation rate, height and shoot dry matter were lower in CLR-384 than in CLR-383. At the ultrastructure level, the leaves of both clones exposed to the herbicides showed thylakoid disorganization and accumulation of starch grains in the chloroplasts. Only plants of CLR-384 were infected by A. psidii, but when exposed to herbicide drift, rust severity was lower than control plants. Six days after inoculation (dai), plants of this clone exposed to the herbicides had smaller uredinia than control plants. At 12 dai, non-herbicide treated plants showed normal uredinia, containing abundant urediniospores. ...
Tropical Plant Pathology, 2017
Tree Genetics & Genomes, 2016
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Papers by Acelino Alfenas