The development of sclerotia of certain fungi

Townsend, Brenda B.; Willetts, H. J.

doi:10.1016/s0007-1536(54)80003-9

Cited by 144 publications

(61 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The chill-induced formation of sclerotia associated with the mycelial bands agrees with the known connection of hyphal strands and localized branching to sclerotial formation in S. rolfsii (Townsend & Willetts, 1954;Willetts, 1972;Henis et al, 1973). The results presented here support the view that restriction of mycelial growth leads to sclerotial formation (Henis et al, 1965;Wheeler & Waller, 1965;Willetts, 1978).…”

Section: Discussionsupporting

confidence: 89%

See 1 more Smart Citation

Induction of sclerotia in Sclerotium rolfsii by short low-temperature treatment

Rawn

1991

Journal of General Microbiology

View full text Add to dashboard Cite

When grown on two agar media in Petri dishes a Sclerotium rovsii Sacc. isolate produced sclerotia in different patterns, predominantly at the colony centre on one medium (glucose/yeast extract) but at the dish wall on the other (glucose/ammonium nitrate). However, on both media a short cold treatment (3 h at 5 "C) of colonies grown at 24 "C temporarily interrupted growth and induced subsequent sclerotial formation in a ring where the colony margin was at the time of the cold shock. A second cold treatment 1 d after the first induced a sclerotial ring but negated the effect of the first treatment. The results support the view that interruption of hyphal growth triggers sclerotial formation.

show abstract

Section: Discussionsupporting

confidence: 89%

“…lb). In the band and the sparser area behind it were hyphal strands (Townsend & Willetts, 1954). At about 5 d a ring of initials appeared in and behind the mycelial band (Fig.…”

Section: Resultsmentioning

confidence: 93%

Induction of sclerotia in Sclerotium rolfsii by short low-temperature treatment

Rawn

1991

Journal of General Microbiology

View full text Add to dashboard Cite

show abstract

“…These were identified as the undifferentiated (UD), sclerotial initiation (SI), sclerotial development (SD) and sclerotial maturation (SM) stages. The UD stage is characterized by highly proliferating hyphae, the SI stage by the appearance of small distinct sclerotial initials formed from highly proliferating interwoven hyphae, the SD stage by the increase of sclerotium size and the SM stage is characterized by sclerotium surface delimitation, internal consolidation and melanin pigmentation, and is often associated with droplet excretion (Townsend & Willetts, 1954). Developmental stages UD, SI, SD and SM for R. solani were reached in 3, 4, 5 and 6 days, respectively, for S. sclerotiorum in 3, 4, 7 and 9 days, respectively, for S. rolfsii in 4, 5, 7 and 9 days, respectively, and for S. minor in 3, 4, 6 and 7 days, respectively.…”

Section: Methodsmentioning

confidence: 99%

Superoxide radical induces sclerotial differentiation in filamentous phytopathogenic fungi: a superoxide dismutase mimetics study

Papapostolou

Georgiou

2010

Microbiology

View full text Add to dashboard Cite

This study shows that the superoxide radical (O 2˙" ), a direct indicator of oxidative stress, is involved in the differentiation of the phytopathogenic filamentous fungi Rhizoctonia solani, Sclerotinia sclerotiorum, Sclerotium rolfsii and Sclerotinia minor, shown by using superoxide dismutase (SOD) mimetics to decrease their sclerotial differentiation. The production rate of O 2˙" and SOD levels in these fungi, as expected, were significantly lowered by the SOD mimetics, with concomitant decrease of the indirect indicator of oxidative stress, lipid peroxidation. INTRODUCTIONSclerotial differentiation is a primitive form of differentiation exhibited by certain phytopathogenic filamentous fungi. It is expressed by four main types of sclerotia (compact bodies of aggregated hyphae), which are loose, terminal, lateral-chained and lateral-simple. These types are represented mainly, but not solely, by Rhizoctonia solani, Sclerotinia sclerotiorum, Sclerotium rolfsii and Sclerotinia minor, respectively (Chet et al., 1967(Chet et al., , 1969Chet & Henis, 1975;Le Tourneau, 1979;Willetts, 1971Willetts, , 1978Willetts, , 1997Willetts & Wong, 1980). These fungi are of great agricultural interest because they cause stem-rot diseases in a wide variety of economically important agricultural crops. Therefore, elucidating the mechanisms of sclerotium biogenesis of these fungi may lead to the development of non-toxic ways to combat plant diseases, which could be used as alternatives to the traditional toxic fungicides. Moreover, understanding sclerotial differentiation is very important because it will help to understand more complex forms of differentiation in other organisms as well as whether their mechanisms share common biochemical pathways.It has been proposed that sclerotial differentiation is related to high oxidative stress (Georgiou, 1997), based on the finding that sclerotium biogenesis in S. rolfsii was accompanied by the accumulation of high levels of lipid peroxidation products. This finding has been supported by other studies that developed into a theory of oxidative stress as an inducer of sclerotial metamorphosis (Georgiou et al., 2006). Specifically, hydroxyl radical scavengers, vitamin C and b-carotene (both also acting as endogenous fungal antioxidants), decreased sclerotial differentiation in S. rolfsii, S. minor, S. sclerotiorum and R. solani. In more recent studies, we demonstrated a strong relationship between the thiol redox state of these fungi and their sclerotial differentiation (Patsoukis & Georgiou, 2007a, b, 2008a. Specifically, in R. solani, S. rolfsii and S. minor, there was a decrease in the total amount of reduced thiols during transformation of the undifferentiated mycelium into sclerotium, which, for S. sclerotiorum was accompanied by an increase in the total oxidized components. Moreover, the antioxidant thiol redox state modulator N-acetylcysteine inhibited sclerotial differentiation in S. rolfsii, R. solani and S. sclerotiorum.Until now, our studies have associated only indirect indicators ...

show abstract

“…In some fungi the sclerotium medulla is divided into distinct zones (Townsend and Willetts, 1954;Chet, Henis and Kislev, 1969) but this seems to be less common than the rather more amorphous arrangement described here for C. lagopus. It has been suggested (Volz and Niederpruem, 1970) that the sclerotial medulla of C. lagopus consists entirely of thin-walled cells.…”

Section: Discussionmentioning

confidence: 52%

STRUCTURE OF AERIAL AND SUBMERGED SCLEROTIA OF COPRINUS LAGOPUS

1975

View full text Add to dashboard Cite

SUMMARYSclerotia were formed in both aerial and submerged parts of the mycelium. In addition a layer of cells with pigmented thick walls (called brown matting) which differentiated at the air/agar interface was interpreted as an aspect of sclerotial behaviour since it was regularly formed by strains which produced submerged sclerotia and was composed of cells of similar structure to those of the outermost layer of the submerged sclerotium. Apart from producing sclerotia and oidiospores the cells of the aerial mycelium remained undifferentiated. In contrast, cells of the submerged mycelium, though initially indistinguishable from those of aerial hyphae, became individually differentiated within about 5 days of growth producing two further novel cell types; inflated cells containing glycogen, and hyaline thick-walled cells. Submerged sclerotia were pale brown in colour, irregularly shaped and about 0.5-1.0 mm in diameter. The only structure which differentiated the submerged sclerotium from the submerged mycelium was the outer rind, a layer of cells with thick, pigmented walls. The central (medulla) region contained the same cell types in the same frequencies as the general submerged mycelium. In sharp contrast the aerial sclerotia were highly organized structures composed of distinct and compact tissues. Mature aerial sclerotia were dark brown to black spheroidal structures up to 0.5 mm in diameter. An outer layer of dead and moribund hyphae surrounded the main body of the sclerotium which was bilayered with an outer rind and inner medulla. The rind was multilayered and consisted of small cells with thick pigmented walls; intercellular spaces were cuticularized. The medulla was a closely packed tissue composed predominantly of hyaline thick-walled cells of the same type as were encountered in the submerged mycelium.

show abstract

The development of sclerotia of certain fungi

Cited by 144 publications

References 4 publications

Induction of sclerotia in Sclerotium rolfsii by short low-temperature treatment

Induction of sclerotia in Sclerotium rolfsii by short low-temperature treatment

Superoxide radical induces sclerotial differentiation in filamentous phytopathogenic fungi: a superoxide dismutase mimetics study

STRUCTURE OF AERIAL AND SUBMERGED SCLEROTIA OF COPRINUS LAGOPUS

Contact Info

Product

Resources

About