Sclerotium Delphinii Research Articles

Determination of Genetic Diversity inSclerotium rolfsiiandSclerotium delphiniiby using RAPD and ISSR Markers

The classification and variability among Sclerotium species was studied by using ISSR and RAPD markers. Based on the amplification pattern and reproducibility of eleven RAPD premiers and seven ISSR primers, the delineating variability among the 13 different crops isolates of Sclerotium rolfsii and 4 isolates of Sclerotium delphinii was analyzed. The primer OPB-16 was found to be the best primer for determination of variability among Sclerotium spp. This primer generated at least 17 bands of 230 -1554 base pairs size. Similar results were obtained with IS-8 primer in ISSR marker amplification studies. Though all the isolates of Sclerotium spp. were genetically variable, they share some common bands indicating phylogenetic relationship among them. The ability of primers to highlight the genetic polymorphism between the isolates varied greatly and on the basis of pooled RAPD and ISSR marker analysis these isolates were classified into five broad groups. RAPD-PCR and ISSR molecular marker analysis were found to be efficient and informative technique for differentiating the genetic variability among Sclerotium species.

Genetic diversity among mycelial compatibility groups of Sclerotium rolfsii (teleomorph Athelia rolfsii) and S. delphinii

The genetic relationships among 132 isolates of Sclerotium rolfsii (teleomorph Athelia rolfsii) collected during 1967–97 from 36 different host species over a wide geographic range representing 13 countries were investigated using mycelial compatibility groupings and RAPD analysis. A smaller group of 15 Sclerotium delphinii isolates from five host species and a limited geographic distribution was also studied. The development of aversion reactions following mycelial pairings of isolates in all possible combinations on potato dextrose agar was used to differentiate 71 mycelial compatibility groups (MCG) in S. rolfsii and five MCG in S. delphinii. Many MCG were unique single-member groups and these generally were found in widely separated geographic regions or countries. There was no clear relationship between host of origin and MCG, except for a majority of isolates of S. rolfsii from turfgrass that belonged to MCG 1. Within a specific geographic region, e.g. California, there usually were several different MCG present, some of which were recovered from the same host species. In addition, specific MCG of S. rolfsii were recovered from widely separated geographic regions as well as different host species, e.g. MCG 1 was recovered from turfgrass, carrot, tobacco, and tomato in California, Georgia, North Carolina, and Mexico, respectively. The extent of genetic diversity within and among MCG of S. rolfsii and S. delphinii was studied using RAPD analysis. Isolates from different MCG could be differentiated by their unique banding patterns using six primers. There were no discernible relationships among the various MCG using UPGMA analysis. Isolates within a particular MCG were also genetically diverse, but shared greater numbers of common bands and clustered together. Only a few members of some MCG in S. rolfsii and S. delphinii that had identical RAPD patterns were considered to be clonally derived. The extent of genetic diversity among isolates of S. delphinii was lower than that observed in S. rolfsii.

Interactions between Coniothyrium minitans and sclerotia

The effect of sclerotia from a host species, Sclerotinia sclerotiorum and three non-host species, Rhizoctonia tuliparum, Sclerotium delphinii and Typhula incarnata on conidial germination, germ tube and mycelial growth of Coniothyrium minitans was examined. Both live and autoclaved sclerotia of all species except S. delphinii stimulated conidial germination and germ tube growth of C. minitans on distilled water or mineral salts agar. Mycelial growth of C. minitans was stimulated by all sclerotia but there was no clear specificity in response to any of the sclerotia tested. The implications of these results to the activity of C. minitans as a mycoparasite of sclerotia are discussed.

The effect of dry conditions on subsequent leakage and rotting of fungal sclerotia

Dried sclerotia of Sclerotium delphinii rotted in moist soil whereas those of Sclerotium cepivorum. Botrytis cinerea and Botrytis tulipae did not. A number of fungi invaded dried sclerotia of S. delphinii in soil, the principal coloniser found in the first sampling being Trichodermu hamatum. Leakage of 14C compounds from dried labelled sclerotia placed in water was rapid and was little affected by variation in leakage temperature from 1 to 25°C or by prolonging the drying period beyond a day. Leakage from dried sclerotia which were allowed to imbibe water through a small part of their surface was much reduced. Sclerotia which were redried after leakage leaked again when returned to water but with all four fungi the first of three leakage cycles gave the highest 14C levels. Loss in dry weight in the first leakage cycle was greater with S. delphinii than with the other three fungi and this may be related to the poor survival of dried sclerotia of S. delphinii in moist soil. Substances lost during leakage appear to originate from within sclerotial hyphae rather than from the hyphal free space.

Non-nutritional factors influencing sclerotium formation in some Sclerotinia and Sclerotium species

Sclerotium formation in Sclerotium delphinii, S. rolfsii and Sclerotinia sclerotiorum is influenced both by light intensity and the duration of the light treatment. Removal of matured sclerotia from colonies results in the production of a further crop of sclerotia. In S. sclerotiorum the time of Sclerotium production by a colony appears to be determined endogenously. The observations suggest that a complex of different factors may be involved in sclerotium morphogenesis.

Water relations in sclerotia of some Sclerotinia and Sclerotium species

Experiments on the desiccation sclerotia of Sclerotinia sclerotiorum, Sclerotium delphinii and S. rolfsii demonstrate that the sclerotium rind does not effectively restrict water loss. Observations on rate of rehydration show that drying of the outer sclerotial tissues does not make them impermeable. The data suggest that survival of sclerotia under desiccating conditions is a property of the individual sclerotial cells.

Studies on germination of sclerotia of Sclerotium delphinii

Sclerotia of Sclerotium delphinii Welch buried at different depths in the field showed little sign of activity but did not survive as well as has been claimed previously. Soil temperatures in this country are always below the optimum for germination and below the minimum for much of the year. Sclerotia are subject to soil fungistasis but are less sensitive than those of many other fungi. Germination was suppressed by volatile materials arising from soil and carbon dioxide was shown to be partly responsible for this effect. Germination of sclerotia on soil was enhanced after a period of desiccation and exudation by sclerotia was similarly affected. Previously dried sclerotia did not rot quickly on soil and some were able to germinate vigorously up to twenty times. Their capacity to do this was dependent upon their size. Germination of sclerotia was stimulated by puncturing the rind and by certain chemical treatments. The rind apparently acts as a physical barrier to germination but stereoscan electron microscope studies of the surface of dried sclerotia did not reveal any cracks through which germination hyphae might emerge.

The biology of Sclerotinia trifoliorum Erikss. and other species of sclerotium ‐forming fungi

SUMMARYThe survival in soil of sclerotia of Sclerotinia trifoliorum, S. sclerotiorum, Sclerotium delphinii and S. rolfii was studied. Those of S. rolfsii disintegrated in less than 1 month, while 95% of those of S. delphinii and Sclerotinia sclerotiorum were recovered after 2 years.Sclerotia of S. trifoliorum placed in soil in March slowly diminished in numbers over the summer months, and in late autumn there was a rapid decrease in those near the surface, as a consequence of apothecial formation. This rapid fall did not occur when sclerotia were buried under clover. Over the winter, sclerotia 1 and 2 in. deep increased in numbers by the formation of secondary sclerotia. Secondary sclerotia also occurred in samples of Sclerotinia sclerotiorum.Soil moisture content affected sclerotial survival, an accelerating decline in numbers being noted up to a soil moisture‐holding capacity of 30%. Above this level, increasing numbers of secondary sclerotia were formed, so that the numbers of sclerotia recovered were sometimes greater than those originally buried.Sclerotia became more liable to decay after producing apothecia, but they did not invariably disappear, and some were capable of forming two or possibly three crops of apothecia in successive years.

The biology of Sclerotinia trifoliorum Erikss. and other species of sclerotium ‐forming fungi

SUMMARYIn studies of the behaviour of sclerotia of Sclerotinia trifoliorum, S. sclerotiorum, Sclerotium delphinii and S. rolfsii it was established that S. trifoliorum and S. sclerotiorum formed apothecia in the field, S. sclerotiorum mainly in spring and S. trifoliorum almost exclusively in autumn. Apothecia were formed from sclerotia down to 2 in. in the soil, the number diminishing with increasing depth. At 6 in., sclerotia developed apothecial stipes up to 21/2 in. long: this limitation was not due to exhaustion of the food reserves of the sclerotia.In S. trifoliorum, apothecial formation was abundant in August, then steadily declined, and ceased in November. Broad red clover was exceptional in stimulating the initial flush in both S. trifoliorum and S. sclerotiorum, but very few apothecia formed subsequently.Mycelial growth from sclerotia of S. trifoliorum and S. sclerotiorum was much sparser, even in sterilized soil, than that from sclerotia of Sclerotium delphinii and S. rolfsii.

Inhibition of the Crown-rot Disease Fungus, Sclerotium delphinii Welch

IN 1952, I reported1 the inhibition in vitro of the crown-rot fungus, Sclerotium delphinii Welch, by two species of Penicillium, P. brevi-compactum and P. charlesii. In vivo experiments were set up to demonstrate the practical utilization of these penicillia as agents in combating the crown-rot fungus disease. For this purpose the penicillia were grown in large quantities in Czapek–Dox medium for seventeen to eighteen days on a rotary shaker at room temperature. The culture fluid was then filtered and the filtrate was poured into standard greenhouse flats, containing soil which had been artificially infested three days before with sclerotia of S. delphinii. Controls were also set up, using Czapek–Dox medium, in flats of similarly infested soil. A few days after filtrates of different concentrations were added to the flats, nine plants of Mazus reptans and Ajuga reptans (two rock-garden plants extremely susceptible to S. delphinii) were planted in each of the different flats.

Fungi inhibiting growth of the crown-rot disease fungus Sclerotium delphinii Welch.

Sclerotium delphinii Welch is recognized as a highly destructive pathogen of a large number of vegetables and ornamental plants. Efforts during the past twenty-five years to develop practical control of this fungus have met with failure. Some investigators reported a slight benefit with chemicals, but the control achieved was far from satisfactory. Chemical tests by Davey and Leach in 19411, on a closely related organism, Sclerotium rolfsii, revealed that, of the seventeen water-soluble chemicals tested, only formalin at dilutions of 1 : 100 and applied at 3 gallons per sq. ft. of soil surface was effective. More recently, chemicals were also tried by Thomas Laskaris, while working on diseases of delphinium at the New York Botanical Garden. Because these and other workers were unsuccessful in finding a chemical control for this highly destructive fungus, an attempt has therefore been made, at the suggestion of Dr. P. P. Pirone, plant pathologist of the New York Botanical Garden, to achieve control by biological methods.

On the Nutrition of Sclerotium delphinii

American Journal of BotanyVolume 35, Issue 6 p. 360-363 Article ON THE NUTRITION OF SCLEROTIUM DELPHINII D. Perlman, D. Perlman 35 Edgehill St., Princeton, New JerseySearch for more papers by this author D. Perlman, D. Perlman 35 Edgehill St., Princeton, New JerseySearch for more papers by this author First published: 01 June 1948 https://doi.org/10.1002/j.1537-2197.1948.tb08093.xCitations: 6AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume35, Issue6June 1948Pages 360-363 RelatedInformation

VITAMIN B1 OR ITS INTERMEDIATES AND GROWTH OF CERTAIN FUNGI

SCHOPFER (1934a, 1934b) reported that Phycomyces Blakesleeanus Burgeff does not grow upon a medium of mineral salts, pure dextrose, asparagine, and water, but grows normally on the same medium to which a minute quantitv of crystalline vitamin B, is added. Schopfer's discovery resulted from a suggestion made to him by Burgeff (Schopfer, 1934c) based on the latter's observation of the effect of crystalline vitamin B1 on the growth of Phycomyces. Other fungi found by Schopfer (1935) to require vitamin B1 include Absidia ranosa, Parasitella simplex, Mucor Ramanmnianus, Dicranophora fulva, Chaetocladium Brefeldi, Choanephora cucurbita, Choan,ephora persicaria, and Pilaria anomala. Earlier reports on the importance of vitamin B1 as a growth factor for the lower plants have been published by various investigators including R. J. Williams (1920, 1930), Lepeschkin (19'24), and others. The conclusive evidence of the importance of vitamin B, (aneurin or thiamin) for the growth of plants depended upon a supply of the pure vitamin, which became available in 1934. We have confirmed Schopfer's report of the effect of vitamin B1 on the growth of Phycomyces BRakcesleeanus, and since there are many organisms which do not grow, or grow poorly, on the common synthetic media (those lacking some natural organic supplement), we have determined the effect of vitamin B1 on a number of fungi. MATERIALS AND METHODS.-In addition to Ph ycomyces Blakesleeanus, a plus strain kindly furnished by A. F. Blakeslee, we have used other organisms secured through the courtesy of W. E. Maneval, J. T. Middleton, or C. M. Tucker. Those furnished by Maneval were Absidia glauca Hagem, Basidiobolus ranarum Eidam, Mortierella sp. no. 11, Mortierella candelabrum v. Tiegham and le Monnier, Mucor circinelloides v. Tiegham, Mucor griseolilacinus Povah, Mucor sp. no. 103, Mucor sp. no. 115, Circinella aspera Lendner, Cunninghamella sp. no. 102, Thamnidium elegans Link, Zygorhynchus Moelleri Vuill, Zygorhynchus sp. no. 111, Rhizopus nigricans Ehrenberg, + and -, Phycomyces nitens (Agardh) Kunze and Schmidt, +, Sphaerulina trifolii Rostr. From Tucker we secured cultures of Phytophthora Boehmeriae Saw., P. cactoram (L. and C.) Schwet, P. cambivora (Petri) Buis, P. capsici Leon., P. cinnamoni Rands, P. colocasiae Racib., P. cryptogea Pethyb. and Laff., P. Drechsleri Tuck., P. palmivora Butler, P. parasitica Dast., P. fagopyri Takimoto; Agaricus campestris Linn., Schizophyllum commune Fr., Sclerotium delphinii Welch, and S. Rolfsii Sac. Middleton furnished cultures of Pythium arrhenomanes Drechsler, P. polycladon Sideris, P.

Studies on the Host Range of Sclerotium delphinii Welch

In a note published previously (8) the writer mentioned that A. J. Mix had made an isolation of Sclerotium delphinii Welch from Ajuga reptans. The organism was observed in a rock garden where in addition to Ajuga it was parasitizing Sedum acre and Lysimachia nummularia. This marked the first time this species had been isolated in Kansas, although Sclerotium rolfsii Sacc., a closely related species, is listed by Bartholomew (1) as occurring in the state. Figure 1, left, is a photograph of the strain of S. delphinii isolated from Ajuga, and, right, a typical culture of S. rolfsii growing on potato dextrose agar slants. In the course of a general study of this isolate from Ajuga it was decided to investigate the host range and make a few comparisons with S. rolfsii. The latter, because of its wide geographical distribution and economic importance as a plant pathogene, has received considerable mention in the literature and is known to be parasitic on nearly two hundred hosts. Sclerotium delphinii, on the other hand, has been reported on only about forty species. These have been compiled and are listed in Table I. Unfortunately some workers gave only the common names for some of the hosts, and where there was doubt as to the correct scientific name, either just the genus name or common name is listed.

The Occurrence of Sclerotium delphinii Welch in Kansas

In the summer of 1933 there was observed in a rock garden in Lawrence a fungus parasitizing a patch of Ajuga reptans L. The following summer the fungus had spread to various parts of the garden, and in addition to Ajuga reptans, was parasitizing Lysimachia nummularia L. and Sedum acre L. Dr. A. J. Mix made isolations from Ajuga on August 9, 1934, and obtained an organism that appeared to be Sclerotium delphinii Welch.1 Growing on potato dextrose agar this fungus exhibited those characteristics that distinguish it from Sclerotium rolfsii Sacc., a closely related species, as listed by Stevens.2 These characteristics include ropy mycelium and concave sclerotia varying widely in size from 0.8 to 5.18mm. in diameter. These sclerotia frequently have pits or depressions on their surface, and are of a buff to tawny to Hay's brown color. A comparison of the fungus from Ajuga made with authentic cultures of Sclerotium rolfsii Sacc. obtained from H. H. Whetzel, L. D. Leach, G. F. Weber, and C. W. Edgerton, and cultures of Sclerotium delphinii Welch from H. H. Whetzel, also proved without doubt that it was Sclerotium delphinii Welch. This is the first time this species has been found in this vicinity, and as far as the literature reveals, in Kansas.