Academic literature on the topic 'Botrytis fabae'

Application of the RAPD methods allowed to clearly characterization of isolates of Botrytis fabae and isolates of B. cinerea. Results from RAPD-PCR analysis indicate different groups. Clusters were related with groups based on conidial morphology, morphological characters of the isolates of Botrytis spp.

Chocolate spot caused by Botrytis cinerea and Botrytis fabae is a serious disease of Vicia faba L. beans. Aggressive infection of that disease can result in severe yield losses (up to 100%). Genetic resistance to chocolate spot in V. faba L. is weak. Chemical control of the disease gives only partial crop protection because of widespread fungicide resistance in both chocolate spot agents. Biological control with applications of bacteria antagonistic to Botrytis may provide a useful alternative to chemicals. Of 270 Bacillus isolates tested, 54 (20%) were found to cause necrosis and (or) chlorosis when placed on leaves of V. faba L. Only 14 strains (6.5%) were able to prevent chocolate spot symptoms from developing in vivo and all of these antagonised Botrytis cinerea and Botrytis fabae in vitro by antibiosis. Bacillus macerans BS 153 was selected for biocontrol experiments in both the greenhouse and field in which plants were sprayed with bacterial suspensions. Detached leaves were inoculated with Botrytis at intervals after Bacillus macerans BS 153 application. The beneficial effect of the biocontrol agent persisted much longer in greenhouse-grown plants. The estimated ED50 was 1.3 times less in the greenhouse spray than in the field spray. From the high number of bacteria required and the rate of decline of introduced Bacillus population in field-grown plants, it was concluded that biocontrol of chocolate spot by Bacillus is impractical unless improved formulations and spray application techniques are developed.Key words: chocolate spot, Bacillus isolates, biocontrol.

Chocolate spot, which is caused by the necrotrophic fungus Botrytis fabae, is a major foliar disease occurring worldwide and dramatically reducing crop yields in faba bean (Vicia faba). Although chemical control of this disease is an option, it has serious economic and environmental drawbacks that make resistant cultivars a more sensible choice. The molecular mechanisms behind the defense against B. fabae are poorly understood. In this work, we studied the leave proteome in two faba bean genotypes that respond differently to B. fabae in order to expand the available knowledge on such mechanisms. For this purpose, we used two-dimensional gel electrophoresis (2DE) in combination with Matrix-Assisted Laser Desorption/Ionization (MALDI-TOF/TOF). Univariate statistical analysis of the gels revealed 194 differential protein spots, 102 of which were identified by mass spectrometry. Most of the spots belonged to proteins in the energy and primary metabolism, degradation, redox or response to stress functional groups. The MS results were validated with assays of protease activity in gels. Overall, they suggest that the two genotypes may respond to B. fabae with a different PSII protein repair cycle mechanism in the chloroplast. The differences in resistance to B. fabae may be the result of a metabolic imbalance in the susceptible genotype and of a more efficient chloroplast detoxification system in the resistant genotype at the early stages of infection.

Botrytis cinerea, B. fabae, and B. fabiopsis are known to cause chocolate spot on broad bean. This study was conducted to develop polymerase chain reaction (PCR)-based assays to detect and differentiate these three species. Two sets of primers, Bc-f/Bc-r for B. cinerea and Bfab-f/Bfab-r for B. fabiopsis, were designed based on two sequence-characterized amplified region markers derived from two random amplified polymorphic DNA assays. The other primer set, Bfa-f/Bfa-r for B. fabae, was designed based on the necrosis and ethylene-inducing protein 1 gene sequence. The three primer sets were highly specific for the corresponding species of Botrytis in both single and multiplex PCR assays. The PCR detection limit was 40, 40, and 400 pg of DNA per 25-μl reaction mixture for B. fabae, B. fabiopsis, and B. cinerea, respectively. Presence of the broad bean DNA in the PCR reactions at 1:1000 (Botrytis DNA/broad bean DNA [wt/wt]) had negligible effects on detection of the targeted Botrytis spp. The multiplex PCR assay was able to detect three Botrytis spp. in artificially infected and naturally infected broad bean leaves. These results suggest that the multiplex PCR assay developed in this study could be used to monitor the epidemics of chocolate spot of broad bean in the field.

Este trabajo de investigación inició de la pregunta de si se produce inhibición en el crecimiento del hongo patógeno Botrytis fabae con el uso de liposomas y nanopartículas de azufre. El objetivo fue explicar cómo utilizando concentraciones 0,001 M de nanopartículas de azufre encapsulado en liposomas de fosfatidilcolina en mezclas de limoneno y octanol, actúan sobre el cultivo in vitro del hongo Botrytis fabae. Durante esta investigación se obtuvieron nanopartículas de azufre. Se demostró que la fosfatidilcolina abarcaba azufre y forma liposomas. Así mismo se identificó el hongo Botrytis fabae por el cultivo in vitro. La impregnación de los discos se realizó inmediatamente en la siembra del hongo y se detectó la inhibición completa por el componente octanol- fosfatidilcolina con nanoparticulas de azufre usados en la síntesis de los liposomas, con una sensibilidad alta de un radio de 45 mm y sin efecto por los liposomas de fosfatidilcolina con limoneno. Comparado con el tratamiento del producto comercial carbendazim, el cual formó un halo de inhibición de 17 mm de radio que corresponde a una sensibilidad intermedia. Se utilizó un diseño experimental completamente al azar (DCA) y el método de sensibilidad en disco.

The primary producers of pulses are small-scale farmers with small and dispersed plots under rain-fed conditions with substantially lower yields of less than 0.9 t/ha as compared to the improved faba bean varieties and international yields. There are many biotic and abiotic factors which hampers faba bean production in Ethiopia. From biotic factors chocolate spot (Botrytis fabae Sard.) is the major fungal disease hampering faba bean production in Ethiopia.). It is a highly prevalent and destructive disease, causing yield loss up to 61% on a susceptible and 34% on tolerant faba bean genotypes in the central highlands. But we can manage this economically important disease in manner which comprises all available diseases management methods in combination that is IPM (Integrated Pest management). So, the objective of this review work was to review available integrated pest management option for management of chocolate spot disease of faba bean in Ethiopia. We can control the disease by using different methods from these late sowing of faba bean, mixed cropping of faba bean with cereal crops and mancozeb spray reduced the disease and increased the grain yield and seed weight over sole and mixed cropping with field pea; also cereal mixing with faba bean has advantages over faba bean mixing with field pea. Suppressive effects can be ascribed to a combination of host biomass reduction, altered microclimate and physical barriers to spore dispersal. Also creation of a physical barrier in the form of non-host plants prevents some of the dispersed spores from being deposited on the host tissue by interception. In Ethiopia, study has revealed that the biological control agents for chocolate spot of faba bean and Bacilli are natural residents of faba bean leaves. Additionally recommendation have been given that, further study has to be done to explore the mode of action by bacillus subtilis against fabae.

SUMMARYThe in vitro resistance of five white and four coloured-flowered lines and cultivars of Vicia faba to seed and root inoculation with spore suspensions of the pathogenic soil-borne fungi, Fusarium culmorum and Pythium debaryanum, was investigated under aseptic conditions in the UK. The presence of foliar diseases was also assessed in the field in 1989/90. White-flowered lines were more susceptible than coloured genotypes to fungal infection during germination but equally resistant during seedling growth. High-tannin containing seed coats had chemical and physical properties which protected seeds against fungal infection during germination. Frequent cracking of the seed coat in a zero-tannin line was associated with a greater fungal contamination of seeds. Resistance to the foliar diseases Uromyces viciae-fabae and Botrytis fabae was not related to flower colour. The results are discussed in relation to emergence in white-flowered types.

Generation of superoxide anion (O2-.) and peroxidase activity were significantly increased in bean leaves infected with incompatible and compatible pathogens: Botrytis fabae and Botrytis cinerea, respectively, but the induction was greater on direct inoculation with B. fabae, than with B. cinerea. A slightly higher O2-. level was also detected in the parts of leaves surrounding the inoculation side. Overproduction of O2-. was observed earlier than the increase in peroxidase activity. Pretreatment of the leaves with methyl jasmonate enhanced both O2-. production and peroxidase activity following inoculation with B. cinerea. Induction of superoxide dismutase activity after the infection was less pronounced than changes in O2-. level. The differences in the rate of NADH oxidation in the extracts from control and inoculated leaves, correlated with the differences in the rate of O2-. production. The results indicate that O2-. level is one of the essential factors responsible for the difference in the interactions between bean plant and compatible and incompatible pathogens.

El cultivo de haba (Vicia faba L.) en el departamento de La Paz, Bolivia, se cultiva al área circunlacustres del Lago Titicaca, zonas próximas del Altiplano (3820- 3200 msnm) y valles interandinos. Tradicionalmente su cultivo ha estado orientado a la producción para consumo en vaina verde. Debido a las condiciones climáticas de la zona, como la elevada humedad del suelo, el cual es determinante para la aparición de enfermedades relacionada estrechamente con la cantidad de precipitación, la mayoría de los hongos fitopatogenos requieren de la presencia de la humedad libre sobre su hospedero o de una alta humedad relativa en la atmósfera, estas enfermedades han ocasionado que el cultivo se encuentre afectado, los cuales disminuyen la cantidad y calidad de la producción de haba en vaina verde y grano seco . El trabajo de investigación se realizó en la comunidad Copacati Alto del Municipio de Copacabana, ubicada a 147 km al norte de la ciudad de La Paz. Geográficamente está situada entre los 16º12' de latitud Sur y a los 69°05' de longitud Oeste, a 4000 m.s.n.m. de altura. Las condiciones climáticas están caracterizadas por una precipitación de 600 mm/año con el 40 a 60% de Humedad y una Temperatura media de 8.6 ºC. El presente trabajo se realizo con el objetivo de controlar la enfermedad de la mancha chocolate Botrytis fabae, el cual se realizo con el producto químico y el extracto natural (Caldo de bordelés, extracto de molle), bajo tres dosis de aplicación 50, 75, 100% respectivamente. Se utilizo el diseño de bloques al Azar con Arreglo Factorial 6 tratamientos y 3 bloques. En cada unidad se evaluó 15 plantas tomadas al azar en los cuales se determino la incidencia, severidad, eficiencia del producto químico y natural, número vainas por planta, longitud de vainas. La dosis utilizada fue de 50, 75, 100% en el extracto como en el producto químico los cuales se asperjaron durante la fase de prefloración, floración y llenado de vainas.

A total of 115 Chinese accessions from six provinces with diverse climate, topography and farming systems were screened for reaction to three fungal diseases Ascochyta blight, (Acochyta fabae), chocolate spot (Botrytis fabae) and Cercospora leaf spot (Cercospora zonata). Not all the accessions were included in three disease screening trials due to a limited number of seeds for some accessions. However, a majority of lines were included in all three disease screening trials and the remaining at least for two trials. In the Ascochyta blight screening trial 96 Chinese accessions were evaluated and while the majority of lines were susceptible a number of lines including 1688, 1689 (Gansu), 1729 (Guangxi), 1750 (Jiangsu), 1998 and 1999 (Qinghai) were identified with a significant degree of heterogeneity including a low proportion of resistant plants. Single plants with a disease score of either 1 (resistant) or 3 (moderately resistant) could be used for the development and selection of resistant lines. The effect of three concentrations of B. fabae inoculum was observed on four cultivars 1714-1, Nura, Fiesta and Icarus. The disease development was proportional to the amount of inoculum irrespective of cultivars but the relative responses of cultivars varied between treatments, consistent with partial resistance. The lines 1714-1 and Icarus were most resistant at all treatments. A medium dose of inoculum provided the opportunity for cv. Nura to express resistance compared to cv. Fiesta, while at a low and high inoculum concentration, there was no significant difference between the two cultivars. A total of 99 Chinese accessions from six provinces were evaluated for chocolate spot resistance. Germplasm from Qinghai, Guangxi, Jiangsu and Gansu were more resistant as compared to germplasm from Yunnan and Guangdong. Qinghai Province lines 1982, 1983, 1988, 1994, 1998 and 1999 were the least susceptible among all the Chinese lines and could be valuable sources of resistance against the chocolate spot disease. A total of 45 faba bean lines, 22 from six different regions of China, identified in the preliminary screening as having some degree of resistance, 13 regional lines previously reported as resistant to chocolate spot and 10 Australian cultivars were evaluated for chocolate spot resistance. Germplasm from Qinghai, Jiangsu and Yunnan regions were comparatively resistant and particularly accessions 1983 and 1985 from Qinghai province showed a moderately resistant reaction. Accession 1714-1, a selection from Acc 1714 from Gansu, was the most resistant among all lines including Icarus and Farah. None of the other Chinese lines was equivalent to Australian resistant cultivars Icarus and Farah. In Cercospora leaf spot screening trial, a total of 72 Chinese accessions and two local check lines were screened for disease resistance. The only resistant line was the local check, however, three lines 1673, 1727 and 1890 from Gansu, Guangxi and Yunnan, respectively expressed a minor level of resistance and there is potential to develop resistant lines through single plant selection from these heterogeneous accessions. There was significant defoliation due to disease. The genetics of inheritance of resistance to A. fabae (isolate 86/03) was investigated in five faba bean lines. The resistance of cvs. Farah and Ascot was under the control of different genes in the two cultivars. The F₂ populations of the crosses of these two cultivars with susceptible cv. Icarus segregated in different distribution patterns for resistance and susceptibility that indicated a dominant gene controls resistance in Farah while resistance in Ascot is controlled by a recessive gene. The cross 1783/2*Ascot (Acc 1783/2 of Tunisian origin) did not segregate in the F₂ generation, with the exception of a single plant rated 5, indicating resistance in both cultivars is controlled by the same gene(s). Two crosses out of three from 1689/1*Ascot (Acc 1689/1 susceptible and of Chinese origin) segregated in the ratio 1:3 indicating the resistant gene of Ascot is recessive to 1689/1. Seventeen isolates of A. fabae from southern Australia were characterised for a number of characters including pathogenicity on cv. Icarus, growth on medium, growth patterns, pycnidial formation and distribution, size of spores and colour. The isolates were variable in most of the features. Pycnidial formation and growth on media were positively associated with disease severity, but there was no association between the other traits in culture with disease severity. This project has identified variation within Chinese germplasm in response to the fungal diseases Ascochyta blight, chocolate spot and Cercospora leaf spot. Lines with a degree of resistance to Ascochyta blight and Cercospora leaf spot were heterogeneous and screening of larger populations of identified lines and selection of individual resistant plants could lead to the development of new resistant lines. Genetic studies of resistance to Ascochyta blight comparing Ascot and Farah confirmed that there are alternative genes controlling resistance, and resistant Chinese lines might provide additional resistance genes. Identification of chocolate spot resistance in Acc 1714-1 is a significant finding as the majority of previously identified sources of resistance to this disease originated from the Andean region. Further characterization and utilization of these new sources of disease resistance should contribute to a long-term strategy of breeding disease resistant faba bean cultivars.
Thesis (M.Ag.Sc.) -- University of Adelaide, School of Agriculture, Food and Wine, 2009