In vitro antagonism of Botrytis cinerea by phylloplane yeasts

2002 ◽  
Vol 80 (8) ◽  
pp. 885-891 ◽  
Author(s):  
James W Buck
Keyword(s):  
Botrytis Cinerea ◽  
Rhodosporidium Toruloides ◽  
Yeast Cells ◽  
Lesion Development ◽  
Nitrogen Base ◽  
Wide Range ◽  
Biocontrol Activity ◽  
Phylloplane Yeasts ◽  
Leaf Disks

The influence of inoculum and nutrient concentrations on the in vitro antagonism of Botrytis cinerea by phylloplane yeasts was investigated with detached leaf disk and conidial germination assays. Rhodosporidium toruloides Y-1091 significantly reduced lesion development after 96 h on geranium leaf disks when co-inoculated at 1 × 106 or 1 × 107 yeast cells/mL with B. cinerea conidia at 1 × 104 or 1 × 105 conidia/mL. No effect on lesion development was observed when yeast and fungus were co-inoculated at a 1:1 ratio. Biocontrol activity of R. toruloides was greatest in 20 mM glucose and 20-fold dilute yeast nitrogen base. Twenty-five phylloplane yeasts exhibited a wide range of biocontrol activity when screened for antagonism of B. cinerea on geranium leaf disks (1 × 106 yeast cells/mL, 1 × 105 conidia/mL). Lesion development was significantly reduced by yeasts initially identified as poor antagonists when inoculated at higher concentrations (5 × 106 or 1 × 107 yeast cells/mL) with B. cinerea. Both poor and good antagonists significantly reduced in vitro germination of B. cinerea conidia. The presence of B. cinerea conidia had a greater effect on the growth of two poor antagonists compared with two good antagonists on leaf disks. These data suggest that many phylloplane yeasts will antagonize B. cinerea under conditions of low nutrient availability and with high antagonist to pathogen ratios.Key words: yeast, biological control, competition, nutrients, germination, Rhodosporidium toruloides.

scholarly journals Effect of Pathogen Aggressiveness and Vinclozolin on Efficacy of Rhodotorula glutinis PM4 Against Botrytis cinerea on Geranium Leaf Disks and Seedlings

Plant Disease ◽  
2004 ◽  
Vol 88 (11) ◽  
pp. 1262-1268 ◽  
Author(s):  
J. W. Buck ◽  
S. N. Jeffers
Keyword(s):  
Botrytis Cinerea ◽  
Biological Control Agent ◽  
Rhodotorula Glutinis ◽  
Control Agent ◽  
Lesion Development ◽  
Biocontrol Efficacy ◽  
Lesion Diameter ◽  
Reduced Rate ◽  
Leaf Disks

Efficacy of the yeast Rhodotorula glutinis isolate PM4 as a biological control agent against 29 isolates of Botrytis cinerea obtained from greenhouse-grown ornamentals was assessed in vitro on geranium leaf disks. Isolates of B. cinerea varied in aggressiveness in the absence of either biological or chemical controls; diameters of lesions produced on leaf disks ranged from 0.8 to 12.3 mm. Efficacy of R. glutinis PM4 against the different isolates of B. cinerea varied greatly; lesion diameters ranged from 0.2 to 10.3 mm when the yeast was present. The yeast significantly reduced lesion development by 16 B. cinerea isolates in each of two replicate trials and by 9 isolates in one of the trials; however, 3 isolates were not inhibited by the yeast on geranium leaf disks. The yeast significantly reduced lesion development by B. cinerea isolate 01, used as a standard for comparison, in four of six trials. Fourteen of the B. cinerea isolates were inoculated onto geranium seedlings and produced a range of lesion sizes (2.9 to 16.4 mm), similar to that produced on leaf disks. Efficacy of the yeast in combination with a reduced rate (0.1×) of the fungicide vinclozolin (50 μg of active ingredient ml-1) was evaluated on geranium seedlings against 10 isolates of B. cinerea that were resistant to vinclozolin. Addition of vinclozolin to the yeast significantly reduced lesion diameter by five of the isolates compared with diameters of lesions produced in the presence of the yeast alone. Lesions produced by nine of the resistant isolates were 2.6 mm or smaller in both trials on plants treated with the mixture of yeast and vinclozolin. The effect of vinclozolin concentration (0 to 500 μg a.i. ml-1) on biocontrol efficacy of R. glutinis PM4 was evaluated using three resistant isolates of B. cinerea and geranium seedlings. Disease control was significantly better at higher concentrations of fungicide for two of the isolates. Linear regression of lesion diameter against vinclozolin concentration showed a significant effect on yeast biocontrol efficacy with B. cinerea isolate FL-2-b (y = 6.20 – 0.63x; r2= 0.74) and isolate BR-1 (y = 4.10 – 0.32x; r2 =0.28) but there was no significant effect with isolate GG-2-b. Overall, PM4 exhibited biocontrol activity on both geranium leaf disks and seedlings against a number of isolates of B. cinerea that varied in aggressiveness. Variability in biocontrol efficacy against isolates resistant to vinclozolin usually was reduced by the addition of vinclozolin.

scholarly journals Combinations of Fungicides with Phylloplane Yeasts for Improved Control of Botrytis cinerea on Geranium Seedlings

2004 ◽  
Vol 94 (2) ◽  
pp. 196-202 ◽  
Author(s):  
J. W. Buck
Keyword(s):  
Disease Control ◽  
Botrytis Cinerea ◽  
Ornamental Plants ◽  
Rhodotorula Glutinis ◽  
Lesion Development ◽  
Biocontrol Efficacy ◽  
Highly Effective ◽  
Cell Densities ◽  
Phylloplane Yeasts

Control of Botrytis cinerea on geranium seedlings was evaluated in treatments with phylloplane yeasts in combination with 10 fungicides used to manage Botrytis blight of ornamental plants. Rhodotorula glutinis PM4 significantly reduced the development of lesions caused by B. cinerea on geranium cotyledons; however, yeast biocontrol efficacy was highly variable between trials. Treatment with the yeast in combination with azoxystrobin or trifloxystrobin at one tenth the labeled rate (7.5 μg a.i. ml-1) or the full labeled rate (7.5 μg a.i. ml-1) reduced lesion development, compared to treatment with the yeast or the fungicide alone. Vinclozolin at half the labeled rate or the full labeled rate (250 or 500 μg a.i. ml-1), in combination with R. glutinis PM4, significantly reduced the development of lesions caused by an isolate of B. cinerea resistant to vinclozolin. Copper hydroxide and iprodione at one-tenth the labeled rates, with or without yeast, were highly effective in limiting lesion development. Mancozeb did not increase the biocontrol efficacy of the yeast, and thiophanate-methyl negatively affected the yeast efficacy. Improved disease control was observed in treatments with vinclozolin at the labeled rate and R. glutinis PM4 at cell densities of 5 × 105 and 1 × 106 cells ml-1, but not 1 × 105 cells ml-1, on seedlings co-inoculated with B. cinerea in a suspension containing 1 × 105 conidia ml-1. Disease control improved in treatments with combinations of vinclozolin and eight other isolates of R. glutinis, two isolates of R. graminis, and two isolates of R. mucilaginosa. Biocontrol was not observed in treatments with two isolates of R. minuta. The combination of yeast and vinclozolin significantly reduced the germination of conidia of B. cinerea and the growth of R. glutinis PM4 in vitro. All combinations of R. glutinis PM4 with azoxystrobin, trifloxystrobin, or vinclozolin provided highly effective and consistent disease control not observed in treatments with the fungicides alone or the yeast alone.

In vitro attachment of phylloplane yeasts to Botrytis cinerea, Rhizoctonia solani, and Sclerotinia homoeocarpa

2004 ◽  
Vol 50 (12) ◽  
pp. 1041-1048 ◽  
Author(s):  
Tom W Allen ◽  
Leon L Burpee ◽  
James W Buck
Keyword(s):  
Rhizoctonia Solani ◽  
Botrytis Cinerea ◽  
Rhodotorula Glutinis ◽  
Extracellular Polysaccharide ◽  
Phytopathogenic Fungi ◽  
Yeast Cells ◽  
Cryptococcus Laurentii ◽  
Sclerotinia Homoeocarpa ◽  
Phylloplane Yeasts

The ability of yeasts to attach to hyphae or conidia of phytopathogenic fungi has been speculated to contribute to biocontrol activity on plant surfaces. Attachment of phylloplane yeasts to Botrytis cinerea, Rhizoctonia solani, and Sclerotinia homoeocarpa was determined using in vitro attachment assays. Yeasts were incubated for 2 d on potato dextrose agar (PDA) prior to experimentation. A total of 292 yeasts cultured on PDA were screened for their ability to attach to conidia of B. cinerea; 260 isolates (89.1%) attached to conidia forming large aggregates of cells, and 22 isolates (7.5%) weakly attached to conidia with 1 or 2 yeast cells attached to a few conidia. Ten yeasts (3.4%), including 8 isolates of Cryptococcus laurentii, 1 isolate of Cryptococcus flavescens, and an unidentified species of Cryptococcus, failed to attach to conidia. All non-attaching yeasts produced copious extracellular polysaccharide (EPS) on PDA. Seventeen yeast isolates did not attach to hyphal fragments of B. cinerea, R. solani, and S. homoeocarpa after a 1 h incubation, but attachment was observed after 24 h. Culture medium, but not culture age, significantly affected the attachment of yeast cells to conidia of B. cinerea. The 10 yeast isolates that did not attach to conidia when grown on agar did attach to conidia (20%–57% of conidia with attached yeast cells) when cultured in liquid medium. Attachment of the biocontrol yeast Rhodotorula glutinis PM4 to conidia of B. cinerea was significantly greater at 1 × 107 yeast cells·mL–1 than at lower concentrations of yeast cells. The ability of yeast cells to attach to fungal conidia or hyphae appears to be a common phenotype among phylloplane yeasts.Key words: adhesion, biological control, Cryptococcus laurentii, Rhodotorula glutinis.

scholarly journals The Endophytic Fungus Albifimbria verrucaria from Wild Grape as an Antagonist of Botrytis cinerea and Other Grape Pathogens

2020 ◽  
Vol 110 (4) ◽  
pp. 843-850 ◽  
Author(s):  
Zhi Li ◽  
Pingping Chang ◽  
Linlin Gao ◽  
Xiping Wang
Keyword(s):  
Botrytis Cinerea ◽  
Chitinase Activity ◽  
Gray Mold ◽  
Vitis Amurensis ◽  
Grape Quality ◽  
Wide Range ◽  
Biocontrol Activity ◽  
Elsinoe Ampelina ◽  
Conidium Germination

Gray mold, caused by Botrytis cinerea, is one of the most prevalent fungal diseases in table and wine grapes, affecting grape quality and yields. In this study, we isolated several endophytic fungi, including Alternaria alternata, Bipolaris cynodontis, Phoma sp., and Albifimbria verrucaria, from leaves of Amur grape (Vitis amurensis) cultivar Shuangyou and investigated their biocontrol activity against B. cinerea. In vitro dual assay showed that A. verrucaria isolate SYE-1 inhibited growth of B. cinerea. The isolate also had a wide range of biocontrol activity against Lasiodiplodia theobromae and Elsinoë ampelina. Mycelial growth and conidium germination of B. cinerea were significantly inhibited by metabolites of A. verrucaria in agar plates and culture extracts of A. verrucaria from liquid culture. The isolate produced a total chitinase activity of 0.4 U/ml after incubation for 10 days in Czapek’s liquid medium. In addition, application of culture extracts of A. verrucaria prior to B. cinerea inoculation significantly reduced disease severity on grape leaves of the susceptible cultivar Red Globe. Taken together, our results indicate that A. verrucaria has potential as a biocontrol agent to control grape gray mold.

scholarly journals Biocontrol activity of microoganisms on Botrytis isolates from vineyards

2020 ◽  
pp. 6-10
Author(s):  
Yara Suhan Juárez-Campusano ◽  
María del Socorro Chávaro-Ortiz ◽  
Lourdes Soto-Muñoz / ◽  
Juan Ramiro Pacheco-Aguilar
Keyword(s):  
Growth Inhibition ◽  
Botrytis Cinerea ◽  
Inhibitory Activity ◽  
Mycelial Growth ◽  
Fruit Rot ◽  
Bacillus Sp ◽  
Physiological Diversity ◽  
Grape Fruit ◽  
Biocontrol Activity

Botrytis cinerea causes postharvest fruit rot of an infinity of crops, the infective capacity is due to its physiological diversity that shown, even inside the same crop. For its control, the use of antagonistic microoganisms is emerging as a sustainable option. In the present work, 40 Botrytis isolates from three vineyards were characterized by their ability to infect grape fruit (Thomson Seedless), the results showed that all produced lesions diameters from 6.5 to 22.2 mm. Ten of these isolates that presented differences in terms of their virulence, were subject to in vitro antagonism test, using the yeasts Metschnikowia sp. NB9 and FLL17 (Kodamaea sp. FLL17 and the bacteria FR4B12 Bacillus sp. R4B12 from must and flower and fruit, respectively. The results showed that, on average, FRB412 had the highest inhibitory activity on the growth of Botrytis strains, exhibiting mycelial growth inhibition percentages from 51 to 81 %, followed by FLL17 (21 to 53 %) and NB9 (15 to 51 %). In conclusion, the three study strains have different ranges of biocontrol on Botrytis, whose application could reduce gray rot in grapes.

scholarly journals Biological Control of Botrytis cinerea: Interactions with Native Vineyard Yeasts from Washington State

2018 ◽  
Vol 108 (6) ◽  
pp. 691-701 ◽  
Author(s):  
Xuefei Wang ◽  
Dean A. Glawe ◽  
Elizabeth Kramer ◽  
David Weller ◽  
Patricia A. Okubara
Keyword(s):  
Botrytis Cinerea ◽  
In Planta ◽  
Meyerozyma Guilliermondii ◽  
Grape Berries ◽  
Yeast Strains ◽  
Seedless Grape ◽  
Biocontrol Activity ◽  
Niche Competition ◽  
Field Deployment

Native yeasts are of increasing interest to researchers, grape growers, and vintners because of their potential for biocontrol activity and their contributions to the aroma, flavor, and mouthfeel qualities of wines. To assess biocontrol activity, we tested 11 yeasts from Washington vineyards, representing isolates of Candida saitoana, Curvibasidium pallidicorallinum, Metschnikowia chrysoperlae, M. pulcherrima, Meyerozyma guilliermondii, Saccharomyces cerevisiae, and Wickerhamomyces anomalus, for ability to colonize Thompson Seedless grape berries, inhibit the growth of Botrytis cinerea in vitro, and suppress disease symptoms on isolated berries. The yeast-like fungus Aureobasidium pullulans was also included based on its known biocontrol activity against B. cinerea in studies on apple and grape. All yeast strains multiplied rapidly in grape berries and reached densities of over log 6 cells per wound as early as 2 days after inoculation with 200 cells. One of the Botrytis isolates used in this study was much less virulent than the others and was provisionally identified as B. prunorum based on multilocus sequence analysis. Suppression of the growth of B. cinerea isolates 111bb, 207a, 207cb, and 407cb occurred on berries treated with A. pullulans P01A006, Metschnikowia chrysoperlae P34A004 and P40A002, M. pulcherrima P01A016 and P01C004, Meyerozyma guilliermondii P34D003, and S. cerevisiae HNN11516. Inhibition of Botrytis isolates by the yeast strains was more common on berries than in vitro, suggesting the possibility that niche competition was a more likely biocontrol mechanism than antibiosis in planta. Metabolic profiling of yeast strains and B. cinerea isolates using Biolog YT plates revealed seven distinct metabolic groups. Furthermore, the yeast strains showed partial to complete tolerance to the commonly used fungicides fluopyram, triflumizole, metrafenone, pyraclostrobin, and boscalid. Implications of these findings for field deployment of native Washington yeasts as biocontrol agents against B. cinerea are discussed.

Regulatory properties of yeast nitrate reductase in situ

1976 ◽  
Vol 22 (1) ◽  
pp. 35-42 ◽  
Author(s):  
V. Prabhakara Choudary ◽  
G. Ramananda Rao
Keyword(s):  
Amino Acids ◽  
Nitrate Reductase ◽  
Nitrogen Starvation ◽  
Yeast Cells ◽  
Vitro Assay ◽  
Wide Range ◽  
In Situ Assay

A simple and rapid procedure to make yeast cells permeable by agitating with toluene–ethanol, (TE) 1:4, v/v was developed. The permeated cells retained their ability to catalyze certain enzyme reactions. Temperature and duration of agitation during TE treatment played an important role in retention of the catalytic potential of permeated cells. The in situ assay using permeated cell preparations was more sensitive even in the absence of added cofactors than the in vitro assay in detecting assimilatory nitrate reductase (NAD(P)H:nitrate oxidoreductase, EC 1.6.6.2) (NAR) activity in Candida utilis.Using in situ assay technique, different mechanisms regulating the biosynthesis of NAR in C. utilis were investigated. Nitrogen starvation did not lead to derepression of NAR. NO3− ions were absolutely essential for induction and maintenance of high levels of NAR activity. Cells grown on ammonium nitrate possessed relatively lower levels of NAR. Kinetics of NAR induction were followed as a function of time and inducer concentration. The influence of various cations on the induction of NAR by nitrate was investigated. A wide range of D-amino acids induced NAR synthesis. Of 22 L-amino acids tested only phenylalanine induced significant levels of NAR. Various intermediates of the pathway of nitrate reduction influenced the rate of NAR induction. There was a rapid disappearance of in vivo activity of the enzyme of induced yeast cells on nitrogen starvation, and the rate of loss was accelerated by the presence of NH4+.

Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

1991 ◽  
Vol 30 (01) ◽  
pp. 35-39 ◽  
Author(s):  
H. S. Durak ◽  
M. Kitapgi ◽  
B. E. Caner ◽  
R. Senekowitsch ◽  
M. T. Ercan
Keyword(s):  
Soft Tissue ◽  
Room Temperature ◽  
Normal Subjects ◽  
Left Testis ◽  
Wide Range ◽  
Activity Ratios ◽  
The Right ◽  
Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

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