Helminthosporium Sp Research Articles

Survey of fungal diseases associated with aerial stems and leaves of potato (Solanum tuberosum L.) in some irrigated fields in Kaduna and Katsina States of Nigeria

A survey was conducted to determine the incidence of fungal diseases associated with aerial stems and leaves of Irish potato (Solanum tuberosum L.) in some irrigated fields in Kaduna and Katsina states. The fields were selected based on systematic random sampling method and the samples were collected using stratified random sampling (SRDS) techniques. Disease symptoms were identified using CABI and CIP description of potato diseases. A total of four fungal diseases were found to be associated with aerial stems and leaves that included early blight (17.8%), leaf blight (48.7%) Fusarium wilt (21.1%) and Sclerotinia wilt (12. 29%). The fungi were identified based on standard mycological methods. The colonies observed were distinguished microscopically and macroscopically. Six genera of fungi were isolated from the wilted aerial stems and blighted leaves as Fusarium sp (18.7%), Sclerotium sp (18.7%) and Alternaria sp (18.7%); Helminthosporium sp (18.7%) had the highest frequency of occurrence. Botrytis sp (17.7%) and Stemphylium sp (5.6%) had the least frequency of occurrence. The results of this study could be used for further studies in plant protection and disease management.

Evaluation of the Antifungal Activity of Bacillusamyloliquefaciens and B. velezensis and Characterization of the Bioactive Secondary Metabolites Produced against Plant Pathogenic Fungi.

Simple SummaryPlant pathogenic fungi cause serious damage in agriculture, resulting in major losses in the yield and the quality of different economic crops. Chemical fungicides are dangerous to human health and the environment. They have many harmful side effects on non-target organisms. Moreover, their residues have been found in human food. Endophytic bacteria could be a valuable and safe alternative method for the biological control of phytopathogenic fungus. The endophyte Bacillus amyloliquefaciens provides a strong prospect as a biocontrol agent against Alternaria sp. on pepper plants.Endophytic bacteria are plant-beneficial bacteria with a broad host range. They provide numerous benefits to their hosts, helping them tolerate several biotic and abiotic stresses. An interest has recently been developed in endophytic bacteria which are producing bioactive compounds that contribute to the biological control of various phytopathogens. This research paper aimed to investigate the potentiality of new local strains of endophytic bacteria such as Bacillus amyloliquefaciens and B. velezensis and the production of several antimicrobial metabolites associated with the biocontrol of Alternaria sp., which cause serious diseases and affect important vegetable crops in Egypt. Twenty-five endophytic bacteria isolates were obtained from different plants cultivated in El-Sharkia Governorate, Egypt. Dual culture technique was used to evaluate the bacterial isolates’ antagonistic potentiality against Alternaria sp. and Helminthosporium sp. The most active bacterial isolates obtained were selected for further screening. The antifungal activity of the most active endophytic bacterial isolate was assessed in vivo on pepper seedlings as a biocontrol agent against Alternaria sp. A significant antifungal activity was recorded with isolates C1 and T5 against Alternaria sp. and Helminthosporium sp. The bacterial endophyte discs of C1 and T5 showed the highest inhibitory effect against Alternaria sp. at 4.7 and 3.1 cm, respectively, and Helminthosporium sp. at 3.9 and 4.0 cm, respectively. The most active endophytic isolates C1 and T5 were identified and the 16S rRNA sequence was submitted to the NCBI GenBank database with accession numbers: MZ945930 and MZ945929 for Bacillus amyloliquefaciens and Bacillus velezensis, respectively. The deformity of pathogenic fungal mycelia of Alternaria sp. and Helminthosporium sp. was studied under the biotic stress of bacteria. The culture filtrates of B. amyloliquefaciens and B. velezensis were extracted with different solvents, and the results indicated that hexane was the most efficient. Gas Chromatography-Mass Spectrometry revealed that Bis (2-ethylhexyl) phthalate, Bis (2-ethylhexyl) ester, and N,N-Dimethyldodecylamine were major constituents of the endophytic crude extracts obtained from B. amyloliquefaciens and B. velezensis. The in vivo results showed that Alternaria sp. infection caused the highest disease incidence, leading to a high reduction in plant height and in the fresh and dry weights of pepper plants. With B. amyloliquefaciens application, DI significantly diminished compared to Alternaria sp. infected pepper plants, resulting in an increase in their morphological parameters. Our findings allow for a reduction of chemical pesticide use and the control of some important plant diseases.

Endophytic Fungi as Potential Agents of Helminthosporium sp. in Rice Plant (Oryza sativa L.)

Brown spot disease is the most serious rice disease due to its destructive nature, wide distribution and presence of several physiological races of the organism. In Asia, the disease has been recorded to reduce crop yields vary broadly from 6-90%. The application of endophytic fungi is reported to increase plant resistance from the secondary metabolites produced. The resulting metabolites are synthesized compounds to maintain their existence in interacting with the environment. The aim of this study was to obtain endophytic fungi of rice plants that were able to suppres Helminthosporium sp. pathogens. Isolation of endophytic fungi was carried out from the roots, peniles, leaves and leaf sheath of rice plants. Identification of endophytic fungi was based on their macroscopic, microscopic characters and molecular identification. Endophytic fungi that had the highest inhibition were T. asperellum, F. nirenbergiae, and F. oxysporum as indicated by the in vitro antagonism test. T. asperellum, F. nirenbergiae, and F. oxysporum also produced IAA hormone between 1.8 to 4.365 mg/L.

Seed quality and mycoflora associated with chickpea (Cicer arientinum L.) seed in Ethiopia

The study was conducted at Ethiopian Institute of Agricultural Research, Haramaya University and Jimma University, Ethiopia. Crop yield is directly associated with the physical and biological quality of planting material or seed. Ninety-nine (99) chickpea seed lot samples were collected for physical purity,seed health and germination tests from major chickpea growing areas in Ethiopia in the 2016/17 cropping season to assess the status of chickpea seed health and quality among subsistence farmers,research stations and seed growers.The seed lots were grouped as researcher saved, farmers saved and seed growers’ saved seed. The maximum physical purity of 97.5% was recorded for the researcher saved seed lots, 90.8% for the seed growers and 87.4 % for the farmers saved seeds. Foreign matters and broken seeds were the most contaminants found in the seed lots. The seed germination percentages were in the range of 96.3% to 98.5% for all seed sources and there were no significant differences among the seed lot samples. A total of seventeen (17) fungi species were isolated from all seed sources with different frequency and amount. These are Fusarium spp., Aspergillus sp., A. niger, A. flavus, A. nidulans, A. candidus, A. fumigatus, Penicillium sp., Rhizopus sp., Verticillium sp., Rhizoctonia sp., Pythium sp.,Alternaria sp., Helminthosporium sp. Phylostica sp., Cladosporium sp., Negrospora sp.Aspergillus flavus was found the most dominant with recovery(Relative Density=21.53%, Infection rate=10.36%, and Infection Frequency=25.59 %)from all seed lots. There were high variations in relative density, Infection rate, and Infection frequency among isolated fungi. Ascochyta rabieithe most important chickpea disease was not found in this study. This might relate to the incidence and prevalence of sample collection season/cropping year which was low in expected areas.The current study concluded that there are seed qualities and seed health management issues with regards to different seed sources (farmers, research and private sectors); this entails strong seed quality control and growers’ awareness creation on storage sanitation, seed health test before sowing, and production of healthy crops. To keep the seed health in a better condition, seed growers should keep a wider interval of rotation, develop use of the healthy improved seed, after some generation (4-5), seed grading to avoid loss of physical purity, use of appropriate storage container (ventilated and clean), seed dressing with safe pesticides, and appropriate moisture level for storage(about 14%)should have to keep.Longer storage also gives a chance to contaminate the whole seed and can expose to decay.

Growth Response of Kopsia (Kopsia arborea Blume) Plants to Applied Endophytic Fungi

The plant always associates with microbes for its life, includes the endophytes. Aim of this study is to examine the effect of endophytic fungi on Kopsia (Kopsia arborea) seed germination and seedling growth. Here, we used endophytic fungus from forest pathology laboratory, namely Phomopsis sp1, Phomopsis sp2, and Helminthosporium sp. All endophytic fungi were combined with liquid fertilizer to assess Kopsia seedling growth. The results showed that the Kopsia seed germinations, which treated with endophytic fungi have a higher value than the control. The endophytic fungi Phomopsis sp1 and Helminthosporium sp could increase the number of leaves without adding liquid fertilizer, while the Phomopsis sp2 needed liquid fertilizer for it. The NPA and the IMB values of the Kopsia seedlings are 0.71-1.71, and 0.18-0.33 strongly indicates the readiness of Kopsia seedlings to plant in the field, respectively.

Processing on the sanitary quality of seeds of Panicum maximum cv. ‘Tanzânia’

ABSTRACT The aim of this study was to evaluate the sanitary quality of seeds of Panicum maximum cv. ‘Tanzânia’, following the several phases of the seed processing process. Seeds were sampled before processing and after leaving the air and screen machine (upper and intermediary screens and bottom); first gravity table (drift, upper and intermediate spouts); second gravity table (upper, intermediate, and lower spouts), and treating machine for dyeing the seeds. The sanitary analyses were conducted according to the filter paper method, with and without superficial disinfestation of the seeds, which were incubated at a temperature of 20 ± 2 °C with photoperiod of 12 h for seven days. Some seed processing steps may reduce the incidence of seeds of P. maximum cv. ‘Tanzania’ contaminated with Phoma sp. and Helminthosporium sp. In general, the processing can increase the incidence of seeds contaminated with Cladosporium sp. and Cercospora sp. The fungi Phoma sp., Helminthosporium sp., Penicillium sp., Cladosporium sp. and Cercospora sp. are found inside and outside the seeds and can be disseminated by the processing machines.

Spectrum of fungal keratitis change in South China

Background Fungal keratitis has a high incidence in China and its clinical treatment is very difficult, and its etiology diagnosis and appraisal is the premise to improve the prognosis of disease.With the changes of regional environment and climate in recent years, whether the spectrum of fungal keratitis change in South China is remarkable. Objective The purpose of this study was to investigate recent pathogenic distribution of fungal keratitis in South China area. Methods The consecutive fungal culture results of 3 350 purulent keratitis at Zhongshan Ophthalmic Center from January 2009 to December 2014 were retrospectively reviewed.The positive rate of fungal culture, genus or species distribution, seasonal distribution and different term distribution were analyzed. Results The culture-positive rate was 31.34% in this study (1 050/3 350), and the average culture-positive number was 175 strains per year.In the positive fungus, the highest positive rate was Fusarium SP (32.10%, 337/1 050), and followed by Aspergillus SP (25.71%, 270/1 050), Heminthosporium SP (14.29%, 150/1 050) and Mucor SP (9.14%, 96/1 050). The fungal culture-positive rate was 36.05% (367/1 018) in 2009 to 2010, 32.45% (324/1 014) in 2011 to 2012, and 26.86% (354/1 318) in 2013 to 2014, respectively, with a significant difference among the three periods (χ2=22.37, P<0.01), showing a decreasing tendency of incidence.Two hundreds and sixty-one strains were isolated from January to March (31.15%, 261/838), 182 strains from April to June (25.53%, 182/713), 237 strains from July to September (30.00%, 237/790), 370 strains from October to December (36.67%, 370/1 009), showing a statistically significant difference among them (χ2=25.19, P<0.01). The number of infectious strains was most during October to December and fewest during April to June. Conclusions The leading pathogenic fungi of fungal keratitis is Fusarium SP and followed by Aspergillus SP, Helminthosporium SP, Mucor SP in turn.Fungal keratitis is usually prevalent from October to December, and its incidence is still rising in Chinese mainland recently.However, the increasing tendency in South China has been prevented in recent six years. Key words: Cornea/microbiology; Corneal ulcer/microbiology; Eye infections, fungal/microbiology; Mycoses/microbiology; Humans; South China

Sanitary quality of Brachiaria brizantha cv. Marandu and Xaraés seeds harvested in different states in Brazil

The incidence of fungi in seeds depends on the sanitary and climatic conditions in which the seeds were produced. So, the objective of this study was to identify the fungi present in commercial lots of Brachiaria brizantha cv. ‘Marandu’ and’Xaraes’ seeds harvested in different areas in Brazil. Seeds from ten lots of each cultivar, produced in the Brazilian states of Mato Grosso do Sul, Mato Grosso, Goias, Minas Gerais, Sao Paulo, and Bahia were evaluated as to moisture content, germination and sanity. The experiment was conducted according to a completely random design with eight replications of 50 seeds for each lot. In both cultivars, the seeds were found to be infected with Aspergillus sp., Chaetomium sp., Curvularia sp., Fusarium sp., and Helminthosporium sp; the highest incidences were those of Chaetomium sp. and Fusarium sp. Seeds of the ‘Marandu’ cultivar were the only ones showing the presence of Phoma sp. and Pyricularia grisea and those of the ‘Xaraes’ cultivar with Colletotrichum sp. and Nigrospora sp. The incidence of Fusarium sp., Aspergillus and Nigrospora sp. reduces ‘Xaraes’ seeds germination whereas it does not interfere in the ‘Marandu’ seeds germination. The presence of the fungus Pyricularia grisea is for the first time reported in tropical forage grass seeds produced in the Southeast and Northeast regions of Brazil.

Foliar disease infection on some forest trees

In a routine survey foliar disease causing fungi were identified as Phytopthora sp. on leaves of Bauhinia varigata, Alternaria sp. on Cordia dichotoma, Helminthosporium sp. and Alternaria sp. on leaves of Azadirachta indica, Helminthosporium sp on leaves of Pterocarpus santalims Alternaria sp. on Ziziphus mauritiana as well as Eagle marmelos and Fusarium sp. on Acacia leucophloea leafs.

Optimization of Citric Acid Production Using Aspergillus niger Isolated from the Leaf Litter Soil of Sathuragiri Hills

Soil samples were collected from the different locations in Sathuragiri Hills (Western Ghats, Tamilnadu). The Total Fungal Counts in the soil samples of the different locations were analyzed. The percentage frequencies of occurrence of fungal isolates are identified. The fungal isolates were identified based on the morphological and cultural characteristics they were identified as Cladosporium sp, Aspergillus niger, Penicillium sp, Alternaria sp, Curvularia sp, Helminthosporium sp and Aspergillus flavus. Among the isolates maximum amount of citric acid levels was produced by Aspergillus niger (2.2 ± 0.001 g/l). The effect of different pH, temperature, carbon source, nitrogen source, incubation time and agricultural residues on citric acid production by Aspergillus niger was analysed. The maximum amount of citric acid production was recorded in pH - 6.0 (2.32 ± 0.09 g/l), temperature - 30℃ (2.85 ± 0.06 g/l), carbon source - Glucose (6.08 ± 0.10 g/l). Nitrogen source - ammonium chloride (10.22 ± 0.05g/l), incubation time - 72 hours (13.56 ± 0.04 g/l) and agricultural residue - corn ears (17.2 ± 0.14 g/l).

Antifungal Effect and Protective Role of Ursolic Acid and Three Phenolic Derivatives in the Management of Sorghum Grain Mold Under Field Conditions

In this study, investigation was carried out under in vitro as well as field conditions to explore inhibitors of sorghum grain mold. Phytochemicals, viz., methyl trans-p-coumarate (AIC-1), methyl caffeate (AIC-2), syringic acid (AIC-3), and ursolic acid (UA), at different concentrations (500, 750, and 1000 ppm) were tested on spore germination of Alternaria alternata, Curvularia lunata, Fusarium moniliforme, F. pallidoroseum, and Helminthosporium sp. Significant growth inhibition (P < 0.001) was observed against all fungi except A. alternata which was found to be resistant to AIC-3. Further, two separate sets of field experiments involving spraying of water and F. moniliforme suspension over chemicals treated (1000 ppm) sorghum panicles were done. The levels of protection varied with different treatments which were graded using a standard 1 - 9 rating scale. The Fusarium-challenged panicles (FCP) showed lesser susceptibility and decreased the rate of infection of grain mold (grade 7.0), compared to simple UA, AIC-2, and AIC-1 treatments (7.4, 7.6, and 8.0 grade, resp.). The HPLC quantification of differentially induced phenolic acids in treated sorghum grains substantiated this effect disclosing the higher accumulation of chlorogenic, vanillic, and salicylic acids in FCP. This might be due to defensive induction of these acids by the plants. Although mold control by examined chemicals were lesser than the standard Tilt (grade 5.9), they were found to be nontoxic to mammalian cells under cytotoxicity assay.

Antifungal Property of Essential Oil Extracted from Zanthoxylum armatum (Timur)

The aim of this research work was to test the effect of essential oil of Zanthoxylum armatum (timur) originated from Salyan (Nepal) against five isolated fungi i.e. Aspergillus sp., Alternaria sp., Penicillium sp., Cladosporium sp. and Helminthosporium sp. The essential oil yield of sample from Salyan was 2.29 %. Different concentrations i.e. 5µl, 10µl, 15µl and 20µl of essential oil were used to determine zones of inhibition. The zone of inhibition was highest against Cladosporium sp. at all concentrations, while it was lower against Penicillium and Helminthosporium sp. MIC values of essential oil of Zanthoxylum armatum were found to be 0.16mg/ml, 0.14mg/ml, 0.4mg/ml, 0.1 mg/ ml and 0.4 mg/ml against Aspergillus sp, Alternaria sp, Penicillium sp, Cladosporium sp and Helminthoaporium sp respectively.

Screening of Some Fungi Isolation of Rice Cultivars in Different Site of Allahabad, Varanasi, Mirzapur, Jaunpur and Chandauli District in Uttar Pradesh

Rice (Oryza sativa L.) one of the staple food crops of 60% of world’s population, suffers from different kinds of diseases caused by fungi. In the present study, five paddy samples were collected from different places of Allahabad, Varanasi, Mirzapur, Jaunpur and Chaundali District of Uttar Pradesh, in India and screened for fungal pathogens using Potato Dextrose Agar plate method. Results showed varied Disease Incidence in collected samples ranging from 56.66% to 83.33%. The variety “BPT-5204” collected from Allahabad showed a minimum DI of 56.66% whereas “Basmati-370” collected from Jaunpur showed 83.33% of maximum of total DI, followed by “Narendra-59” from Mirzapur 80%, “Sonam” from Chandauli which showed 73.33% DI and “Rupali” collected from Varanasi which showed 63.33% DI. Highest fungus frequency was recorded in rice variety Basmati-370 and lowest fungus frequency was found in BPT-5204. Seven fungal species namely Penicillium, Helminthosporium sp, Fusarium sp., Aspergillus niger; Aspergillus ochraceus, Altrnaria sp., and Aspergillus clavatus in all the five samples have been recorded. Key word: Isolation, seed born fungi, rice varieties.

Effect ofAnnona muricata,Abutilon indicumandEvolvulus alsinoidesextract on spore germination of sorghum grain mold fungi

Sorghum grain mold fungi like Alternaria solani, Curvularia lunata, Fusarium moniliforme and Helminthosporium sp, were tested with hexane fraction (AMIE-HF), chloroform fraction (AMIE-CF), ethyl acetate fraction (AMIE-EAF), crude extract (AMIE) of Annona muricata, petroleum ether extract of Abutilon indicum (AIPE) and alkaloid enriched fraction of Evolvulus alsinoides (EAMAA I). AMIE HF at 1000, 2500 and 5000 ppm and AMIE EAF at 2500 and 5000 ppm concentration showed significant effect on F.moniliforme while AMIE CF and AMIE showed no effect. AIPE remarkably inhibited A.solani at all concentrations and C.lunata at 2500 and 5000 ppm concentration. EAMAA I inhibited spore germination of A.solani at 1000, 2500 and 5000 ppm whereas C.lunata at 5000 ppm concentration.

Effect of essential oils of medicinal plants on leaf blotch in Tanzania grass

Leaf spots caused by phyto-pathogenic fungi, can reduce the production of forage plants. The essential oils of medicinal plants have antimicrobial potential. The objective here was to evaluate the fungotoxicity in vitro of the essential oils of lemongrass (Cymbopogon citratus (DC.) Stapf (Poaceae)), citronella (Cymbopogon nardus (L.) Rendle (Poaceae)), lemon balm (Lippia alba (Mill.) NE Br ex Britton & P. Wilson (Verbenaceae)) and peppermint (Mentha piperita L. (Lamiaceae)) on the fungus Helminthosporium sp. and the in vivo effect of these oils and of commercial neem oil (Azadirachta indica A. Juss. (Meliaceae)) on leaf blotch in Panicum maximum Jacq. cv. Tanzania-1. The mycelial growth of the fungus was evaluated over five periods (2; 4; 6; 8 and 10 days from incubation) and with five concentrations of essential oils (C1 = 250 ppm; C2 = 500 ppm; C3 = 750 ppm; C4 = 1,000 ppm e C5 = 1,250 ppm). As an alternative control, the preventative and curative effect on leaf blotch of five oil-based treatments were evaluated: lemongrass, citronella, lemon balm, peppermint and neem in four concentrations (2,500; 5,000; 7,500 and 10,000 ppm). The essential oils of lemongrass and citronella were the most effective in reducing mycelial growth of Helminthosporium sp. With the essential oil of lemongrass, the pathogen presented the highest growth concentration (1.250 ppm). The results obtained showed that all the essential oils and concentrations tested presented a preventive and curative effect, reducing the severity of leaf blotch.

MICROBIOLOGICAL AND PHYSICOCHEMICAL QUALITIES OF PLANTAIN FLOUR SOLD IN SOME MARKETS IN BENIN CITY

The microbiological, physicochemical and nutritional (proximate) qualities of plantain flour samples obtained from various markets located within the Benin City metropolis evaluated using standard methods. Microbial isolates identified include; Staphylococcus aureus, S. epidermidis, Bacillus subtilis, Micrococcus sp, Enterobacter aerogenes, Klebsiella sp, Pseudomonas aeruginosa, Aspergillus flavus, Aspergillus niger, Penicillium spp., Geotrichum sp, Mucor sp, Trichoderma sp and Helminthosporium sp. Statistical analysis showed that there was a significant difference in the groups of microorganisms (P&gt;0.05). The study also revealed that the carbohydrate and moisture content were relatively high, while fat and titratable acidity values were relatively low. The presence of a high bioload and variety of microorganisms some of which are of public health concern, detected and isolated from the flour samples, may be attributed to inadequate sanitary condition and poor handling practices in the production of plantain flour.

Enantiocomplementary preparation of ( S)- and ( R)-mandelic acid derivatives via α-hydroxylation of 2-arylacetic acid derivatives and reduction of α-ketoester using microbial whole cells

Forty one microorganisms belonging to different taxonomical groups were used to carry out the enantioselective reduction of methyl benzoylformate to afford the corresponding ( R)-methyl mandelate, with moderate to high ee. In contrast, the monooxygenase enzyme in Helminthosporium sp. CIOC3.3316 catalyzed the hydroxylation of methyl 2-phenylacetate to ( S)-methyl mandelate. This combination of oxidation and reduction biotransformations thus provides a method for preparing the enantiomers of chiral α-hydroxy acid derivatives.

Avaliação da atividade antifúngica de extratos de gengibre e eucalipto &lt;em&gt;in vitro&lt;/em&gt; e em fibras de bananeira infectadas com &lt;em&gt;Helminthosporium&lt;/em&gt; sp

The present work aimed to evaluate the fungitoxicity of ginger (Zingiber officinalis) and eucalypt’s (Corymbia citriodora) aqueous crude extracts (ACE) concerning the Helminthosporium sp fungus. This pathogen was identified in the fibers of banana pseudostem, used in local handicraft production. The fungus mycelial growth and sporulation were evaluated in vitro, as well as the growth of fungus colony on banana fibers treated with these plant extracts. The fibers received the following treatments: preventative, curative and T0 (the inoculation process and the treatments with the ACEs were used at the same time). The in vitro results showed that the eucalypt crude extract was the most efficient in mycelial growth and in reduction of spores production. As for the in vivo treatment, it was observed that fibers, preventatively treated with eucalypt ACE, were not affected by Helminthosporium sp.

Antifungal Activity of Bacillus thuringiensis Chitinase and Its Potential for the Biocontrol of Phytopathogenic Fungi in Soybean Seeds

ABSTRACT: Bacillus thuringiensis var israelensis was used to produce chitinase on shrimp wastes by fermentation at 30°C and 250 rpm for 120 h. The enzyme was concentrated by ultrafiltration and was adjusted to pH 5.8. Antifungal chitinase activity on phytopathogenic fungi was investigated in growing cultures and on soybean seeds infested with Sclerotium rolfsii. Fungal inhibition was found to be 100% for S. rolfsii; 55% to 82% for A. terreus, A. flavus, Nigrospora sp, Rhizopus sp, A. niger, Fusarium sp, A. candidus, Absidia sp, and Helminthosporium sp; 45% for Curvularia sp; and 10% for A. fumigatus (P &lt; 0.05). When soybean seeds were infected with S. rolfsii, germination was reduced from 93% to 25%; the addition of chitinase (0.8 U/mg protein) increased germination to 90%. B. thuringiensis chitinase may contribute to the biocontrol of S. rolfsii and other phytopathogenic fungi in soybean seeds in Integrated Pest Management programs.

Biotransformation of ?-ketosulfides to produce chiral ?-hydroxysulfoxides

The biotransformations of a series of substituted phenylthio-2-propanone and benzylthio-2-propanone were carried out using Helminthosporium sp. NRRL 4671, Mortierella isabellina ATCC 42613, or Rhodococcus erythropolis IGTS8. Several products gave microbial oxidation of sulfide to sulfoxide and reduction of carbonyl to secondary alcohol, producing beta-hydroxysulfoxides in medium to high enantiomeric and diastereomeric purities. Fungal biotransformations using Helminthosporium sp. and M. isabellina resulted in the opposite sulfoxide configurations of various beta-hydroxysulfoxide products.