Isolation and identification of pathogen of Dendrobium officinale gray mold and its prevention and control / 中国中药杂志

Through investigation,it was found that the main disease of leaves was grey mold on Dendrobium officinale in Hubei province,which has a great impact on the yield and quality of D. officinale. The identification of morphological and molecular biological was used to prove that the pathogen was Botrytis cinerea. Through test the effect of 5 plant source fungicides and 4 antibiotic fungicides on mycelial growth of strain HS1,which proved 0. 3% eugenol had the best inhibitory effect,EC50 was 0. 29 mg·L-1,the second was1% osthol and EC50 was 1. 12 mg·L-1,the EC50 of 0. 5% matrine was 9. 16 mg·L-1,the EC50 of the other six fungicides was higher than 10 mg·L-1. The field control effect test proved that 0. 3% eugenol had the best control effect,reaching 89. 44%,secondly for 1%osthole,which was 77. 17%,0. 5% matrine was in the third place with 62. 37% of effective rate. However,the control effect of the other fungicides was less than 60%. The three plant-derived fungicides were safe for the produce of D. officinale and showed no phytotoxicity. The effect of these fungicides on the growth of D. candidum was tested,and proved that all the fungicides were safe and harmless to D. candidum. This study provides a research basis for the safe and effective prevention and control gray mold of D. officinale.

Pathogenicity and transmission of fungi detected on Passiflora alata seeds / Patogenicidade e transmissão de fungos detectados em sementes de Passiflora alata

Passion fruit is usually propagated by seeds because of the ease and lower cost in seedling production. However, the seed is the most efficient agent for the spread of pathogens. The damages from seed-borne diseases occur mainly during the germination stages or at the formation of seedlings in nurseries. Considering the need for knowledge on the pathology of sweet passion fruit seeds, the objective was to evaluate the transmission and pathogenicity of the fungi Alternaria sp., Botrytis fabae, Cladosporium cladosporioides, Fusarium spp. and Lasiodiplodia theobromae, known as potentially pathogenic to this crop, and isolated from sweet passion fruit seeds. Therefore, tests on seed health, germination and seedling emergence in a sterilized commercial substrate were conducted using seeds from this species, inoculated with those fungal isolates. Leaves, stems and fruit from this plant were also inoculated with the same fungi. Alternaria sp., Fusarium spp. and L. theobromae were identified in seedlings obtained from inoculated seeds, confirming the transmission of these fungi by seeds. L. theobromae was also considered the most harmful fungus to passion fruit crop, as it causes seed rot and other disease symptoms on the leaves, stem and fruit. These findings inferred that healthy seeds of sweet passion fruit are essential for producing seedlings and to prevent the spread of the diseases caused by these fungi to exempt areas.(AU)

O maracujazeiro geralmente é propagado por meio de sementes em virtude da facilidade e do menor custo na produção de mudas. No entanto, a semente é o agente mais eficiente de disseminação de patógenos, sendo que os danos decorrentes das doenças transmitidas por elas ocorrem principalmente durante os estágios de germinação ou na formação de mudas nos viveiros. Considerando a necessidade de informações acerca da patologia de sementes de maracujá-doce nesse contexto, objetivou-se obter informações sobre a transmissão e a patogenicidade dos fungos Alternaria sp., Botrytis fabae, Cladosporium cladosporioides, Fusarium spp. e Lasiodiplodia theobromae, isolados de sementes de maracujá-doce e potencialmente patogênicos à cultura. Para tanto, testes de sanidade, germinação e emergência de plântulas em substrato comercial esterilizado foram conduzidos com sementes dessa espécie, inoculadas com esses isolados. Folhas, colo e frutos dessa planta também foram inoculados com os mesmos fungos. Alternaria sp., Fusarium spp. e L. theobromae foram identificados em plântulas obtidas de sementes inoculadas, confirmando a transmissão por sementes. L. theobromae foi considerado o mais agressivo à cultura do maracujá, por ter causado podridão nas sementes, além de maiores lesões nas folhas, no colo da planta e nos frutos. Dessa forma, infere-se que a obtenção de sementes de maracujá-doce sadias é imprescindível para a produção de mudas, evitando-se assim a disseminação desses patógenos em áreas isentas.(AU)

Modelo de predicción para Botrytis cinerea en un viñedo de Galicia (España) / Predictive model for Botrytis cinerea in a vineyard of Galicia, Spain

Se realizó un recuento de las esporas de Botrytis cinerea en la atmósfera de un viñedo de la comarca del Ribeiro (Galicia, España), durante tres años consecutivos. Para explicar su abundancia, dicha información se ha relacionado con las fases fenológicas de la vid y con la influencia que los principales parámetros meteorológicos ejercen sobre el contenido fúngico. Tras el estudio estadístico de los datos se ha elaborado un modelo predictivo (regresión polinomial) de la concentración de dichas esporas en la atmósfera.

During three consecutive years, the counting of Botrytis cinerea spores in the atmosphere of a vineyard in the region of Ribeiro (Galicia, Spain) has been carried out. To explain their abundance, such information has been related to the phonological stages of the vine and to the influence that the main meteorological parameters exert on the fungal content. Taking into account the statistical analysis of data, a predictive model (polynomial regression) for the concentration of these spores in the atmosphere has been prepared.

Arabidopsis thaliana: A model host plant to study plant-pathogen interaction using Chilean field isolates of Botrytis cinerea

One of the fungal pathogens that causes more agriculture damage is Botrytis cinerea. Botrytis is a constant threat to crops because the fungus infects a wide range of host species, both native and cultivated. Furthermore, Botrytis persists on plant debris in and on the soil. Some of the most serious diseases caused by Botrytis include gray mold on vegetables and fruits, such as grapes and strawberries. Botrytis also causes secondary soft rot of fruits and vegetables during storage, transit and at the market. In many plant-pathogen interactions, resistance often is associated with the deposition of callose, accumulation of autofluorescent compounds, the synthesis and accumulation of salicylic acid as well as pathogenesis-related proteins. Arabidopsis thaliana has been used as a plant model to study plant-pathogen interaction. The genome of Arabidopsis has been completely sequenced and this plant serves as a good genetic and molecular model. In this study, we demonstrate that Chilean field isolates infect Arabidopsis thaliana and that Arabidopsis subsequently activates several defense response mechanisms associated with a hypersensitive response. Furthermore, we propose that Arabidopsis may be used as a model host species to analyze the diversity associated with infectivity among populations of Botrytis cinerea field isolates...

Generation and analysis of expressed sequence tags from Botrytis cinerea

Botrytis cinerea is a filamentous plant pathogen of a wide range of plant species, and its infection may cause enormous damage both during plant growth and in the post-harvest phase. We have constructed a cDNA library from an isolate of B. cinerea and have sequenced 11,482 expressed sequence tags that were assembled into 1,003 contigs sequences and 3,032 singletons. Approximately 81% of the unigenes showed significant similarity to genes coding for proteins with known functions: more than 50% of the sequences code for genes involved in cellular metabolism, 12% for transport of metabolites, and approximately 10% for cellular organization. Other functional categories include responses to biotic and abiotic stimuli, cell communication, cell homeostasis, and cell development. We carried out pair-wise comparisons with fungal databases to determine the B. cinerea unisequence set with relevant similarity to genes in other fungal pathogenic counterparts. Among the 4,035 non-redundant B. cinerea unigenes, 1,338 (23%) have significant homology with Fusarium verticillioides unigenes. Similar values were obtained for Saccharomyces cerevisiae and Aspergillus nidulans (22% and 24%, respectively). The lower percentages of homology were with Magnaporthe grisae and Neurospora crassa (13% and 19%, respectively). Several genes involved in putative and known fungal virulence and general pathogenicity were identified. The results provide important information for future research on this fungal pathogen.