Effect of temperature during sclerotial formation, sclerotial dryness, and relative humidity on myceliogenic germination of sclerotia of Sclerotinia sclerotiorum

1998 ◽  
Vol 76 (3) ◽  
pp. 494-499 ◽  
Author(s):  
H C Huang ◽  
C Chang ◽  
G C Kozub
Keyword(s):  
Relative Humidity ◽  
Sclerotinia Sclerotiorum ◽  
Hyphal Growth ◽  
Effect Of Temperature ◽  
Limited Growth ◽  
Moist Sand ◽  
Sclerotial Formation ◽  
Seed Rot ◽  
Myceliogenic Germination ◽  
Exogenous Nutrients

A study was conducted to determine the effect of sclerotial dryness, temperature during sclerotia formation, and relative humiditiy during incubation on myceliogenic germination of sclerotia of two isolates of Sclerotinia sclerotiorum (Lib.) De Bary. In the absence of exogenous nutrients, sclerotia germinated more readily at 100% RH than at 95% RH or lower. Desiccation of sclerotia is an important factor affecting myceliogenic germination and hyphal growth. At high humidity, either in an atmosphere with 100% RH or on moist sand, desiccant-dried sclerotia germinated readily and produced vigorous hyphal growth that often developed into colonies. On the other hand, fresh, untreated sclerotia germinated less readily and produced limited growth of hyphae that rarely developed into colonies. There was generally no effect of temperature at which sclerotia formed on germination. The incidence of seed rot and seedling wilt of sunflower was significantly (p < 0.05) higher when desiccant-dried sclerotia were used as inoculum rather than fresh sclerotia.Key words: Sclerotinia sclerotionum, sclerotia, myceliogenic germination, sclerotinia wilt of sunflower, relative humidity.

Comparative studies on myceliogenic germination of tan sclerotia of Sclerotinia sclerotiorum and Sclerotium rolfsii

1989 ◽  
Vol 67 (5) ◽  
pp. 1395-1401 ◽  
Author(s):  
H. C. Huang ◽  
S. K. Sun
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Room Temperature ◽  
Sclerotium Rolfsii ◽  
Soil Surface ◽  
Time Lapse ◽  
Potato Dextrose Agar ◽  
Damping Off ◽  
Seed Rot ◽  
Myceliogenic Germination ◽  
Exogenous Nutrients

Tan-colored sclerotia of Sclerotium rolfsii and of an aberrant strain of Sclerotinia sclerotiorum that were freshly harvested from 5-week-old cultures on potato dextrose agar or stored at room temperature in paper bags for 4 weeks germinated myceliogenically on moist field soil without exogenous nutrients. A comparative study by time-lapse photomicroscopy revealed similarity in the mode of myceliogenic germination of sclerotia of the two species. The germination appeared to be of the hyphal type in both species and was characterized by the emergence of individual hyphae through the rind. There was no evidence of eruptive type of germination in any of the strains tested. Although several hyphae often emerged through the same spot of the rind, these hyphae emerged singly, and the time-lapse photomicrographs showed no evidence of eruptive germination. While most of the germinated sclerotia of S. rolfsii developed into colonies within 4 days of incubation on moist soil, the development of colonies from germinating sclerotia of S. sclerotiorum appeared to be slow, taking up to 28 days. Results of the inoculation studies showed that mycelia from the germinated sclerotia of S. rolfsii were able to infect and cause seed rot and damping-off of canola and alfalfa, which were planted near the soil surface at a distance of at least 15 mm from the sclerotium, without providing exogenous nutrients.

scholarly journals Mycosynthesis of Silver Nanoparticles Using Screened Trichoderma Isolates and Their Antifungal Activity against Sclerotinia sclerotiorum

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1955 ◽  
Author(s):  
Ali Athafah Tomah ◽  
Iman Sabah Abd Alamer ◽  
Bin Li ◽  
Jing-Ze Zhang
Keyword(s):  
Silver Nanoparticles ◽  
Antifungal Activity ◽  
Sclerotinia Sclerotiorum ◽  
Direct Interaction ◽  
Hyphal Growth ◽  
Interaction Patterns ◽  
Fungal Cell ◽  
Trichoderma Species ◽  
Sclerotial Formation ◽  
Myceliogenic Germination

To control the disease caused by Sclerotinia sclerotiorum, a total of 15 isolates of the Trichoderma species was screened for the biosynthesis of silver nanoparticles (AgNPs). Among them, the highest yield occurred in the synthesis of AgNPs using a cell-free aqueous filtrate of T.virens HZA14 producing gliotoxin. The synthetic AgNPs were charactered by SEM, EDS, TEM, XRD, and FTIR. Electron microscopy studies revealed that the size of AgNPs ranged from 5–50 nm and had spherical and oval shapes with smooth surfaces. Prepared AgNPs interacted with protein, carbohydrate and heterocyclic compound molecules, and especially, interaction patterns of AgNPs with the gliotoxin molecule were proposed. The antifungal activity assays demonstrated that percentage inhibition of the prepared AgNPs was 100, 93.8 and 100% against hyphal growth, sclerotial formation, and myceliogenic germination of sclerotia at a concentration of 200 μg/mL, respectively. The direct interaction between nanoparticles and fungal cells, including AgNPs’ contact, accumulation, lamellar fragment production and micropore or fissure formation on fungal cell walls, was revealed by SEM and EDS. These will extend our understanding of the mechanisms of AgNPs’ action for preventing diversified fungal disease.

Effect of temperature on melanization and myceliogenic germination of sclerotia of Sclerotinia sclerotiorum

1989 ◽  
Vol 67 (5) ◽  
pp. 1387-1394 ◽  
Author(s):  
H. C. Huang ◽  
E. G. Kokko
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Cell Walls ◽  
Potato Dextrose Agar ◽  
Effect Of Temperature ◽  
Brown Pigment ◽  
Normal Strain ◽  
Color Intensity ◽  
Electron Dense Material ◽  
Moist Sand ◽  
Myceliogenic Germination

While sclerotia of the normal strain of Sclerotinia sclerotiorum produced on potato-dextrose agar at 7, 16, and 30 °C were black, the color of sclerotia of the aberrant strain was light brown, brown or tan, and dark brown or greyish black under 7, 16, and 30 °C, respectively. In the normal strain, deposition of melanin substance was heavy both on the surface and inside the cell walls of the rind of black sclerotia formed at 16 and 30 °C, but in sclerotia formed at 7 °C, many of the rind cells were unmelanized or partially melanized. In sclerotia from the aberrant strain, an electron-dense material, smaller than the melanin particles of the black sclerotia, was present in trace amounts or absent in light-brown sclerotia formed at 7 °C, but it was more abundant in dark-brown or greyish black sclerotia formed at 30 °C. Despite marked differences in color, sclerotia of the aberrant strain produced at the three temperatures were capable of undergoing myceliogenic germination on moist sand. It is concluded that temperature affects cell wall melanization during sclerotial morphogenesis, and that myceliogenic germination of sclerotia of S. sclerotiorum was affected by the black pigment but was unaffected by the color intensity of the brown pigment.

scholarly journals Heat-dried sclerotia of Sclerotinia sclerotiorum myceliogenically germinate in water and are able to infect Brassica napus

2018 ◽  
Vol 69 (8) ◽  
pp. 765 ◽  
Author(s):  
D. W. Lane ◽  
L. G. Kamphuis ◽  
M. C. Derbyshire ◽  
M. Denton-Giles
Keyword(s):  
Brassica Napus ◽  
Sclerotinia Sclerotiorum ◽  
Host Plants ◽  
Incubation Temperature ◽  
Phytopathogenic Fungus ◽  
Nutrient Source ◽  
Abiotic Conditions ◽  
Moist Sand ◽  
Myceliogenic Germination

The phytopathogenic fungus Sclerotinia sclerotiorum forms dormant structures (termed sclerotia) that germinate myceliogenically under certain environmental conditions. During myceliogenic germination, sclerotia produce hyphae, which can infect leaves or stems of host plants directly from the ground; this is termed basal infection. This study determined which abiotic conditions were most important for promoting myceliogenic germination of sclerotia in vitro. A high sclerotium hydration level and low incubation temperature (15°C) improved mycelial growth in the presence of a nutrient source. Sclerotia incubated without a nutrient source on moist sand, vigorously myceliogenically germinated most frequently (63%) when they had been previously imbibed and then conditioned at −20°C. By far the most consistent amount of vigorous myceliogenic germination (>75%) was produced when sclerotia were heat-dried before being submerged in water. The hyphae of these sclerotia were shown to infect and proliferate on leaves of intact Brassica napus plants. This research provides a better understanding of the abiotic conditions that are likely to increase the risk of basal infection by S. sclerotiorum.

Effect of Temperature, Relative Humidity and Light on Aflatoxin BlProduction in Neem and Datura Seeds

1991 ◽  
Vol 29 (3) ◽  
pp. 197-202 ◽  
Author(s):  
H. K. Chourasia ◽  
A. K. Roy
Keyword(s):  
Relative Humidity ◽  
Effect Of Temperature

Responses of soil microorganisms to volatile exudates from germinating pea seeds

1985 ◽  
Vol 63 (6) ◽  
pp. 1040-1045 ◽  
Author(s):  
J. M. Norton ◽  
G. E. Harman
Keyword(s):  
Soil Microorganisms ◽  
Sclerotium Rolfsii ◽  
Hyphal Growth ◽  
Soil Microbial Activity ◽  
Soil Microflora ◽  
Natural Soil ◽  
Soil Microbial ◽  
Aged Seed ◽  
Seed Rot ◽  
Pea Seeds

Responses of soil microorganisms to volatile exudates from germinating pea seeds of differing quality were determined. Germination of sclerotia of Rhizoctonia solani and Sclerotium rolfsii and subsequent hyphal growth were stimulated by exposure to volatiles from aged but not nonaged pea seeds. Hyphae grew preferentially toward aged seeds. In natural soil, bacterial and fungal populations showed significant increases after exposure to volatiles from aged seed. For example, Fusarium spp. and Pseudomonas spp. showed increases of 79 and 2200%, respectively, over their original population levels after a 48-h exposure to volatiles. Conversely, Pythium populations and associated seed-rotting potential of soil decreased in natural soils exposed to volatiles. In autoclaved soils infested with P. ultimum (PHP4), Pythium populations increased dramatically after exposure to volatiles from aged pea seeds. In soils infested with either soil fungi or bacteria in addition to P. ultimum, Pythium levels remained constant or decreased, respectively, with time of exposure. Exposure to the volatiles from aged pea seeds stimulated soil microbial activity. These results suggest that Pythium germlings, when unable to reach a host, are subjected to microbial antagonism in the presence of the native soil microflora. A decrease in cucumber seed rot coincided with decreases in Pythium numbers.

scholarly journals Effect of temperature and relative humidity in refrigerator on quality traits and storage characteristics of Pre-packed Hanwoo loin

2014 ◽  
Vol 41 (4) ◽  
pp. 415-424 ◽  
Author(s):  
Kuk-Hwan Seol ◽  
Ki Hyun Kim ◽  
Young Hwa Kim ◽  
Kyung Eun Youm ◽  
Mooha Lee
Keyword(s):  
Relative Humidity ◽  
Effect Of Temperature ◽  
Quality Traits ◽  
And Storage ◽  
Storage Characteristics
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