Isolation, identification, and pathogenicity research of brown rot pathogens from Gastrodia elata / 中国中药杂志

Brown rot is a common disease in the cultivation and production of Gastrodia elata, but its pathogens have not been fully revealed. In this study, the pathogenic fungi were isolated and purified from tubers of 77 G. elata samples with brown rot. Pathogens were identified by the pathogenicity test and morphological and molecular identification. The pathogenicity of each pathogen and its inhibitory effects on Armillaria gallica were compared. The results showed that 119 strains of fungi were isolated from tubers of G. elata infected with brown rot. Among them, the frequency of separation of Ilyonectria fungi was as high as 42.01%. The pathogenicity test showed that the pathogenicity characteristics of six strains of fungi were consistent with the natural symptoms of brown rot in G. elata. The morphological and molecular identification results showed that the six strains belonged to I. cyclaminicola and I. robusta in the Nectriaceae family of Sordariomycetes class, respectively. Both types of fungi could produce pigments, conidia, and chlamycospore, and the growth rate of I. cyclaminicola was significantly higher than that of I. robusta. The comparison of pathogenicity showed that the spots formed by I. cyclaminicola inoculation were significantly larger than those of I. robusta inoculation, suggesting I. cyclaminicola was superior to I. robusta in pathogenicity. The results of confrontation culture showed that I. cyclaminicola and I. robusta could signi-ficantly inhibit the germination and cordage growth of A. gallica. A. gallica also inhibited the growth of pathogens, and I. cyclaminicola was less inhibited as compared with I. robusta. The results of this study revealed for the first time that I. cyclaminicola and I. robusta were the pathogens responsible for G. elata brown rot.

Association Study Between Rhizoma Gastrodia elata Brown-rot and Soil Microbial Communities / 中国实验方剂学杂志

Objective:To study the microbial community composition and diversity of brown-rot Gastrodia elata and its surface soil，in order to explain the relationship between brown-rot G. elata and soil microflora in G. elata planting process and provide theoretical basis for revealing the reasons of G. elata brown-rot disease. Method:Used internal transcribed spacer region（ITS） and 16S rDNA high-throughput sequencing technologies to detect the microbial diversity，community structure composition and community structure similarity of fungi and bacteria in healthy tuber，Brown-rot tuber，healthy soil and Brown-rot soil. Result:Compared with health groups，the number of fungi and bacteria operational taxonomic units（OTUs） was increased in brown-rot G. elata and its soil， and the abundance and diversity of fungi and bacteria in brown-rot G. elata soil were significantly decreased. The diversity of fungi in the tubers of brown-rot G. elata was significantly reduced，while the diversity of bacteria was significantly decreased. At the genus level， Mortierella was dominant fungi genus in healthy tuber and healthy soil，which was reduced 7.62% and 15.75% respectively in brown-rot tuber and brown-rot soil. And the dominant bacteria genus was Bradyrhizobium and Burkholderia-Paraburkholderia respectively. Ilyonectria was dominant fungi genus in brown-rot tuber and brown-rot soil，the dominant bacteria genus was Serratia and Bradyrhizobium respectively. Conclusion:The fungal flora in the tuber of brown-rot G. elata had a very high degree of similarity to that in the surrounding soil. These results indicated that the change of soil microbial fungal community caused the occurrence of G. elata brown-rot disease to a certain extent. And the pathogenic fungal Ilyonectria was dominant genus in fungi community of brown-rot tuber and brown-rot soil. Ilyonectria may have the main G. elata brown-rot disease pathogen.

Identification of a novel strain, Streptomyces blastmyceticus JZB130180, and evaluation of its biocontrol efficacy against Monilinia fructicola / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Peach brown rot, caused by Monilinia fructicola, is one of the most serious peach diseases. A strain belonging to the Actinomycetales, named Streptomyces blastmyceticus JZB130180, was found to have a strong inhibitory effect on M. fructicola in confrontation culture. Following the inoculation of peaches in vitro, it was revealed that the fermentation broth of S. blastmyceticus JZB130180 had a significant inhibitory effect on disease development by M. fructicola. The fermentation broth of S. blastmyceticus JZB130180 had an EC50 (concentration for 50% of maximal effect) of 38.3 µg/mL against M. fructicola, as determined in an indoor toxicity test. Analysis of the physicochemical properties of the fermentation broth revealed that it was tolerant of acid and alkaline conditions, temperature, and ultraviolet radiation. In addition, chitinase, cellulase, and protease were also found to be secreted by the strain. The results of this study suggest that S. blastmyceticus JZB130180 may be used for the biocontrol of peach brown rot.

Identification of a novel strain, Streptomyces blastmyceticus JZB130180, and evaluation of its biocontrol efficacy against Monilinia fructicola / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Peach brown rot, caused by Monilinia fructicola, is one of the most serious peach diseases. A strain belonging to the Actinomycetales, named Streptomyces blastmyceticus JZB130180, was found to have a strong inhibitory effect on M. fructicola in confrontation culture. Following the inoculation of peaches in vitro, it was revealed that the fermentation broth of S. blastmyceticus JZB130180 had a significant inhibitory effect on disease development by M. fructicola. The fermentation broth of S. blastmyceticus> JZB130180 had an EC50 (concentration for 50% of maximal effect) of 38.3 μg/mL against M. fructicola, as determined in an indoor toxicity test. Analysis of the physicochemical properties of the fermentation broth revealed that it was tolerant of acid and alkaline conditions, temperature, and ultraviolet radiation. In addition, chitinase, cellulase, and protease were also found to be secreted by the strain. The results of this study suggest that S. blastmyceticus JZB130180 may be used for the biocontrol of peach brown rot.

Caracterización del crecimiento miceliar de cepas nativas de Neolentinus ponderosus y N. lepideus en diferentes pH y degradación de madera de Pinus spp / Mycelial growth of native strains of Neolentinus ponderosus and N. lepideus at different pH and their Pinus spp. wood degradation

Neolentinus ponderosus y N. lepideus son dos especies de hongos saprobios que poseen uso alimenticio tradicional en comunidades de los departamentos de Huehuetenango y Totonicapán, Guatemala. La capacidad degradadora de ambas especies les confiere potencial para el estudio de la producción de cuerpos fructíferos a nivel de sustrato, por lo que en esta investigación se evaluó el crecimiento de una cepa nativa de N. ponderosus y una de N. lepideus en el medio de cultivo agar extracto de malta (EMA) a diferente pH y también se estudió la degradación de la madera de dos especies de pino (Pinus tecunumanii y P. ayacahuite) en cámaras de podredumbre durante 12 meses. El mayor diámetro de crecimiento miceliar de la cepa N. ponderosus se observó a pH 7.0, en tanto que para N. lepideus se obtuvo a pH 5.0 y 5.6. Las colonias de ambas cepas evidenciaron textura afelpada, borde regular a irregular, color blanco, con o sin pigmento difusible, olor frutal, hifas de 1.0-5.0 µm de diámetro, con clamidosporas y fíbulas. La madera de P. tecunumanii degradada por la cepa de N. ponderosus y la madera de P. ayacahuite por la cepa N. lepideus, presentaron porcentajes de pérdida de peso de 8.76 (±5.58) y 12.07 (±5.66), respectivamente y en ambos casos se alcanzó solamente el estadio temprano de degradación. Los resultados de este estudio sientan las bases para investigaciones posteriores en los que se evalúe el cultivo en troncos de ambas especies para la producción de cuerpos fructíferos con fines alimenticios y comerciales

Neolentinus ponderosus and N. lepideus are two saprophytic fungi species used traditionally in Huehuetenango and Totonicapán, Guatemala. The degradative capacity of both species confers them potential for fruiting bodies production. This study evaluated the mycelial growth of two native strains of N. ponderosus and N. lepideus in malt extract agar (EMA) at different pH and the degradation of wood from two pine species in rot chambers during 12 months. pH 7.0 was the most appropriate for the mycelial growth of N. ponderosus and for N. lepideus were 5.0 and 5.6. The colonies of both strains showed fruity odor, velvety texture, regular to irregular edge, white color, with or without diffusible pigment, hyphae with 1-5 µm width, chlamydospores and clamp connections. Wood from Pinus tecunumanii and P. ayacahuite exhibit weight-loss percentages between 8.76 ± 5.58 and 12.07 ± 5.66, with N. ponderosus 145.2003 and N. lepideus 90.2002, respectively. In both cases reached the early stage of brown-rot decay. These results could be useful for future research that evaluate the fruiting bodies production in logs for food and commercial purposes

Screening and Evaluation of Streptomyces Species as a Potential Biocontrol Agent against a Wood Decay Fungus, Gloeophyllum trabeum

Two-hundred and fifty-five strains of actinomycetes isolated from soil samples were screened for their antagonistic activities against four well-known wood decay fungi (WDF), including a brown rot fungus, Gloeophyllum trabeum and three white rot fungi Donkioporia expansa, Trametes versicolor, and Schizophyllum commune. A dual culture assay using culture media supplemented with heated or unheated culture filtrates of selected bacterial strains was used for the detection of their antimicrobial activity against four WDF. It was shown that Streptomyces atratus, S. tsukiyonensis, and Streptomyces sp. greatly inhibited the mycelial growth of the WDF tested compared with the control. To evaluate the biocontrol efficacy of S. atratus, S. tsukiyonensis, and Streptomyces sp., wood blocks of Pinus densiflora inoculated with three selected Streptomyces isolates were tested for weight loss, compression strength (perpendicular or parallel to the grain), bending strength, and chemical component changes. Of these three isolates used, Streptomyces sp. exhibited higher inhibitory activity against WDF, especially G. trabeum, as observed in mechanical and chemical change analyses. Scanning electron microscopy showed that cell walls of the wood block treated with Streptomyces strains were thicker and collapsed to a lesser extent than those of the non-treated control. Taken together, our findings indicate that Streptomyces sp. exhibits the potential to be used as a biocontrol agent for wood decay brown rot fungus that causes severe damage to coniferous woods.

Molecular characterization of a novel thermostable laccase PPLCC2 from the brown rot fungus Postia placenta MAD-698-R

Background Laccase has been considered important for the degradation of lignocellulose by wood rot fungi. The properties and functions of laccase in white rot fungi have been investigated extensively, but those from brown rot fungi remain largely unknown. In this paper, a laccase isoform Pplcc2 from the brown rot fungus Postia placenta MAD-698-R was expressed heterologously in Pichia pastoris GS115, purified and the properties of the enzyme were determined. Results The molecular weight of the protein was determined to be 67 kDa using SDS-PAGE. It cannot oxidize syringaldazine (SGZ), but it can oxidize 2,2'-azino-di-(3-ethylbenzothialozin-6-Sulfonic acid) (ABTS) and 2,6-dimethoxyphenol (DMP). Specific activity for ABTS was 1960 ± 19 Unit/mg. The catalytic constant (k cat) was 1213 ± 18.3 s-1 for ABTS and 293.2 ± 21.9 s-1 for DMP. Km was 22.08 µM for ABTS and 11.62 µM for DMP. The optimal pH for the oxidation of ABTS and DMP was 3.5 and 5.0 respectively. The optimal temperature for the oxidation of ABTS and DMP was 60°C. Conclusions This is the first identified thermo activated and thermostable laccase in brown rot fungi. This investigation will contribute to understanding the roles played by laccases in brown rot fungi.

Monitoramento da biodeterioração da madeira de três espécies amazônicas pela técnica da colorimetria / Monitoring of biodeterioration of three Amazonian wood species by the colorimetry technique

This work aimed to evaluate the use of colorimetry in the characterization of biodeterioration marupá, jequitibá and cumaru wood, submitted to white and brown rot. For this purpose, specimens of each Amazonian species were submitted to accelerated decay tests, according to American Society for Testing and Materials - ASTM D2017, during 20 weeks. With a colorimeter, the colorimetric parameters L* (lightness), a* (green-red coordinate), b* (blue-yellow coordinate) and total color change (ΔE) were determined weekly until the fourth week, and then every two weeks until the twentieth week. Additionally, it was determined the mass loss. The results indicated that the colorimetry was effective in monitoring of biodeterioration of wood, as well as to differentiate white and brown rot. The best predictions of natural resistance to white and brown rot were obtained with the parameters b* and L*, respectively. We also emphasizes the use of ΔE to estimate the biodeterioration of wood, because of their significant correlations with weight loss.

Objetivou-se avaliar o emprego da colorimetria na caracterização da biodeterioração das madeiras de marupá, jequitibá e cumaru submetidas ao ataque de fungos de podridão branca e parda. Para tanto, corpos de prova de cada espécie amazônica foram submetidos a ensaios de apodrecimento acelerado, de acordo com a American Society for Testing and Materials - ASTM D2017, durante 20 semanas. Os parâmetros colorimétricos L* (luminosidade), a* (coordenada verde-vermelho), b* (coordenada amarelo-azul) e a variação total da cor (ΔE) foram determinados semanalmente até a quarta semana, e posteriormente a cada duas semanas até a vigésima semana, com auxílio de um espectrofotocolorímetro. Adicionalmente, foram determinadas as perdas de massa dos corpos de prova. Os resultados permitiram destacar que a colorimetria foi eficaz no monitoramento da biodeterioração da madeira, bem como para diferenciação da podridão branca e parda. As melhores predições da resistência natural aos fungos de podridão branca e parda foram obtidas com os parâmetros b* e L*, respectivamente. Enfatiza-se também, o emprego da ΔE como parâmetro auxiliar na estimativa da biodeterioração da madeira, em razão de suas correlações significativas com a perda de massa.

Dureza Rockwell da madeira de três espécies amazônicas submetidas a ensaios de apodrecimento acelerado / Rockwell hardness of the wood of three Amazon species submitted to decay accelerated tests

Objetivou-se avaliar o emprego de ensaios de dureza Rockwell na caracterização da biodeterioração das madeiras de Simarouba amara (marupá), Cariniana micrantha (jequitibá) e Dipteryx odorata (cumaru), submetidas ao ataque dos fungos apodrecedores Trametes versicolor (podridão branca) e Gloeophyllum trabeum (podridão parda). Para tanto, corpos de prova de cada espécie amazônica foram submetidos a ensaios de apodrecimento acelerado, de acordo com a ASTM D2017 (2005), durante 20 semanas. A caracterização da dureza Rockwell foi realizada semanalmente até a 4ª semana e, posteriormente, a cada duas semanas, até a 20ª semana. Adicionalmente, foram determinadas as perdas de massa, conforme critérios estabelecidos pela ASTM D2017 (2005). Quanto aos resultados, destaca-se que a dureza Rockwell pode ser empregada como ferramenta principal na caracterização da biodeterioração da madeira, sendo sensível na predição dos estágios iniciais. Dentre as madeiras amazônicas, o cumaru apresentou a maior resistência natural aos fungos apodrecedores. Com relação aos fungos, a podridão parda atacou mais intensamente as três madeiras amazônicas.

This study aimed to evaluate the use of Rockwell hardness in the characterization of the biodeterioration of Simarouba amara (marupá), Cariniana micrantha (jequitibá) e Dipteryx odorata (cumaru) woods, which were submitted to decay fungi Trametes versicolor (white rot) and Gloeophyllum trabeum (brown rot). For this purpose, specimens of each Amazon species were submitted to decay fungi, according to ASTM D2017 (2005). The characterization of the Rockwell hardness was performed weekly until the fourth week, and then every two weeks until the twentieth week. Additionally, it was determined the mass loss, according to criteria established by ASTM D2017 (2005). The results indicated that the Rockwell hardness can be used as a primary tool in the characterization of the biodeterioration of wood, being sensitive in predicting the early stages. Among the Amazon woods, cumaru wood showed a greater natural resistance to decay fungi. With respect to decay fungi, brown rot more intensely attacked the three Amazon woods.

Characterization of a Brown Rot Fungus Isolated from Dwarf Flowering Almond in Korea

The fruits showing brown rot symptom on dwarf flowering almond were found in Gongju, Chungchungnam-Do in Korea in July 2005. Small water-soaked lesions on the fruits were initiated, and gradually developed to soft rot covered with gray conidia. Then the diseased fruits were shrunk and became grayish-black mummies. A fungus was isolated from the diseased fruit and its morphological, cultural and molecular genetic characteristics were investigated. Typical blastospores of Monilinia spp. were observed under a light microscope both from tissues of the diseased fruits and from PDA-grown cultures. The fungus grew well at 25degrees C and on PDA. The ITS ribosomal DNA region (650 bp) of the fungus was amplified by PCR and analyzed. Comparative data on ITS sequence homology among Monilinia spp., ITS sequence-based phylogram and morphological characteristics showed that the fungus is Monilinia fructicola. This is the first report on Monilinia fructicola causing brown rot on fruits of dwarf flowering almond in Korea.