Sensibilidad in vitro de Trichoconiella padwickii a diversos principios activos usados como fungicidas en el cultivo del arroz / In vitro susceptibility of Trichoconiella padwickii to various active ingredients used as fungicides in the cultivation of rice

El objetivo de este trabajo fue evaluar in vitro la sensibilidad micelial de Trichoconiella padwickii a diferentes principios activos por medio del cálculo de la concentración inhibitoria media (CI50). Para ello se realizaron siembras de discos de inóculo en agar poroto con distintas concentraciones (0,1; 1; 10; 30, 50; 100 y 1.000 mg/l) de diversos fungicidas. A los 7 días se midió el diámetro de crecimiento de la colonia (cm). Los datos obtenidos se ajustaron a modelos de regresión no lineal. La sensibilidad se clasificó utilizando la escala de Edgington. Los resultados obtenidos demuestran que el patógeno es muy sensible a los productos que actúan sobre la cadena respiratoria (quinone outside inhibitors QoI y succinate dehydrogenase inhibitors SDHI) y la membrana celular (multisitio), y moderadamente sensible a los que interfieren en la división celular (metil benzimidazol carbamatos MBC), en la síntesis de ácidos nucleicos (fenilamidas PA) y en la transducción de la señal osmótica (actividad multisitio). Este trabajo es el primer antecedente sobre la sensibilidad in vitro de T. padwickii a principios activos fungicidas.

The aim of this study was to evaluate in vitro the mycelial susceptibility of Trichoconiella padwickii to different active ingredients through average median concentration IC50 calculation. Inoculum disks were seeded on bean agar at different concentrations (0.1; 1; 10; 30, 50; 100 and 1000 mg/l) of various fungicides. After seven days the colony diameter was measured. The data obtained were fitted to nonlinear regression models. Susceptibility was classified using the scale proposed by Edgington. The results show that the pathogen is very sensitive to products that act on the respiratory chain (quinone outside inhibitors QoI and succinate dehydrogenase inhibitors SDHI) and cell membrane (multi-site contact activity), and moderately sensitive to those products interfering with cell division (methyl benzimidazole carbamates MBC), synthesis of nucleic acids (phenylamides PA) and osmotic signal transduction (multi-site contact activity). This work is the first record on the sensitivity of T. padwickii.

Detection of endogenous bacteria of Gardenia seed and comparative study of chemical treatments / 中国药学杂志

OBJECTIVE: To study the endophytic fungi in the seeds of Gardenia from different regions, identy the strains carried by the seed surface and interior, and compare the treatment effects of different fungicides, to provide reference for the antibacterial treatment before gardenia seed sowing and fungal disease control. METHODS: Plate method was used for the surface and internal detection of Gardenia seeds from 15 countries in China, method of seed dressing was used for seed treatment and disinfection effects of 6 kinds of fungicides is done. RESULTS: Main flora in surface of the seed are genus Fusarium, Mucor, Penicillium, Aspergillus and Rhizopus, Penicillium and Aspergillus are the dominant species.There is no significant difference in this 5 species of the seeds from different places, but significant difference in isolation frequency.Load capacity of the spore range from (6.7±11.5) to (1333.3±230.1) per seed. There is significant difference in spore load from different places.Endophytic fungi inside the seeds are mainly Aspergillus, Penicillium, Mucor, Rhizopus and etc.There is significant difference in seeds of these fungi, it ranges from (1.7±2.9)% to (58.3±17.6)%. Carrier rate and species of fungal among different habitats are significantly different, discrete frequency of Aspergillus is the highest. CONCLUSION: The six antiseptics provided all have kill and inhibition to Gardenia seed fungus in some extent. Bactericidal effects of carbendazim fernasan and carbendazim are the poorest, and fernasan ziram and oxadixyl mancozeb and evil frost are the best, which can achieve above 95.0%. Suggestion is made to choose fernasan ziram and oxadixyl mancozeb as inhibiting fungus agents of Gardenia seed disinfection treatment.

Phylogenetic Status of an Unrecorded Species of Curvularia, C. spicifera, Based on Current Classification System of Curvularia and Bipolaris Group Using Multi Loci

A seed-borne fungus, Curvularia sp. EML-KWD01, was isolated from an indigenous wheat seed by standard blotter method. This fungus was characterized based on the morphological characteristics and molecular phylogenetic analysis. Phylogenetic status of the fungus was determined using sequences of three loci: rDNA internal transcribed spacer, large ribosomal subunit, and glyceraldehyde 3-phosphate dehydrogenase gene. Multi loci sequencing analysis revealed that this fungus was Curvularia spicifera within Curvularia group 2 of family Pleosporaceae.

Efficacy of Bioagents Against Seed Borne Fungi of Rice.

The effect of different antagonist ’ viz. Trichoderma viride Pseudomonas fluorescens and Bacillus substilis were evaluated against different seed borne fungi of rice by dual culture technique. Among three bio agents Trichoderma viride (42.59 to 73.33%) followed by Bacillus subtilis and Psuedomonas fluorescens over control. Significant suppression of radial mycelial growth of Drechslera oryzae by Trichoderma viride, and Trichoderma harzianum in dual culture and Inhibition of Curvularia lunata causing black kernel in rice with Bacillus subtilis (97.77%) followed by Trichoderma viride (96.44%) and Trichoderma harzianum (93.50%) in dual culture method.

Efficacy of Bioagents Against Seed Borne Fungi of Black Gram.

The effect of different antagonists’ viz. Trichoderma viride, Pseudomonas fluorescens and Bacillus subtilis were evaluated against different seed borne fungi of black gram by dual culture technique. Among three bioagents, Bacillus subtilis exhibited maximum mycelial growth inhibition of Phoma medicaginis (73.70%), Fusarium solani (57.60%), Curvularia lunata (44.53%) followed by Pseudomonas fluorescens with Macrophomina phaseolina (62.41%) and Fusarium oxysporum (59.97%) respectively.

Antifungal activity of some medicinal plants on Soybean seed-borne Macrophomina phaseolina.

Soybean Glycine max (L.) Merr. seeds, pods and seedlings are susceptible to fungal attack due to its rich nutrient content. The most commonly isolated soybean (JS-335) seed-borne fungi were Fusarium spp., Macrophomina phaseolina., Pythium spp., Aspergillus spp., Phoma spp., and Phomopsis spp. Macrophomina phaseolina is an important plant pathogenic fungus that causes charcoal rot of soybean and infects more than 500 hosts. In humid climates, the fungus causes a post emergence damping-off of soybean seedlings leading to 50% of crop losses. The objective of this work was to study the efficacy of the botanicals on soybean seed-borne Macrophomina phaseolina. Among the 10 botanicals screened, Datura metel (L.) methanol leaf extract showed the most promising activity against Macrophomina phaseolina.

Seed-borne Brachycladium penicillatum Intercepted under Plant Quarantine Inspection in Korea

A fungus detected from the importing seeds of Papaver rhoeas under plant quarantine inspection in Korea was identified as Brachycladium penicillatum Corda. It differed in morphological characteristics from a similar species, B. papaveris, which was known to form no macroconidiophores and no microsclerotia. Since the first interception in 2006, this fungus has frequently been found from importing seeds of Papaver spp. It was detected from 31 out of 282 seed consignments imported from 2006 to 2011. To prevent its introduction to Korea, the seed consignments infested by B. penicillatum were destroyed or reshipped.

The Effect of Seed-borne Mycoflora from Sorghum and Foxtail Millet Seeds on Germination and Disease Transmission

The seed-borne mycoflora of sorghum and foxtail millet collected from different growing areas in South Korea were isolated and taxonomically identified using dry inspection, standard blotter and the agar plate method. We investigated the in vitro and in vivo germination rates of disinfected and non-disinfected seeds of sorghum and foxtail millet using sterilized and unsterilized soil. The percent recovery of seed-borne mycoflora from the seed components of sorghum and foxtail millet seeds was determined and an infection experiment using the dominant species was evaluated for seedling emergence and mortality. A higher number of seed-borne fungi was observed in sorghum compared to that of foxtail millet. Eighteen fungal genera with 34 fungal species were identified from the seeds of sorghum and 13 genera with 22 species were identified from the seeds of foxtail millet. Five dominant species such as Alternaria alternata, Aspergillus flavus, Curvularia lunata, Fusarium moniliforme and Phoma sp. were recorded as seed-borne mycoflora in sorghum and 4 dominant species (Alternaria alternata, Aspergillus flavus, Curvularia lunata, Fusarium moniliforme) were observed in foxtail millet. The in vitro and in vivo germination rates were higher using disinfected seeds and sterilized soil. More seed-borne fungi were recovered from the pericarp compared to the endosperm and seed embryo. The percent recovery of seed-borne fungi ranged from 2.22% to 60.0%, and Alternaria alternata, Curvularia lunata and 4 species of Fusarium were isolated from the endosperm and embryo of sorghum and foxtail millet. Inoculation of the dominant seed-borne fungi showed considerable mortality of seedlings. All the transmitted seed-borne fungi might well be a primary source of infection of sorghum and foxtail millet crops.

Occurrence of Alternaria cassiae in Seeds of Sickle Senna in Korea

Alternaria cassiae Jurair & Khan was recorded on seeds of sickle senna(Cassia tora L.). Seed infection ranged from 25~45% in two samples. Developing roots and shoots turn brown and died in case of severe infection. Detailed descriptions were given on the habit characters of the fungus and on the morphology of conidiophores and condia. This is the first report of A. cassiae on seeds of Cassia.