The effect of light and temperature on the sporulation of different isolates of <i>Alternaria solani</i>

Douglas, Dexter R.

doi:10.1139/b72-077

Cited by 7 publications

(9 citation statements)

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“…This protocol is effective for production of massive amounts of inoculum when strict aseptic conditions are not required (Walker, 1980). Both the quality and the amount of light are critical for sporulation of A. solani (Leach, 1962;Douglas, 1972). In the present work, greater sporulation was obtained under alternated regime of light (12 h photoperiod).…”

Section: The Adapted and Validated Protocol Allowed Efficient Inductimentioning

confidence: 56%

“…In the present work, greater sporulation was obtained under alternated regime of light (12 h photoperiod). This alternation simulates conditions required for conidial formation, as conidiophore formation occurs under irradiation and conidium formation during the dark period (Lukens, 1960;Leach, 1967;Waggoner & Horsfall, 1969;Douglas, 1972;Walker, 1980). Wavelengths near 310 ηm, provided by black light, stimulate sporulation of A. solani and the conidiophores do not revert to vegetative hyphae when exposed to the dark, allowing conidial formation (Aragaki et al, 1973).…”

Section: The Adapted and Validated Protocol Allowed Efficient Inductimentioning

confidence: 99%

“…In vitro sporulation of A. solani is favored by incubation under continuous fluorescent light (λ = 380 �� 775 ηm) at 25 o C or 16 h photoperiod at 20 o C (Douglas, 1972) and under black light (near ultraviolet �� NUV, λ = 320 �� 400 ηm) and 12 h photoperiod at 25 o C (Fourtouni et al, 1998). However, the spectrum of fluorescent light contains inhibitory wavelengths, especially the blue wavelengths (Honda & Nemoto, 1984).…”

Section: Introductionmentioning

confidence: 99%

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In vitro production of conidia of Alternaria solani

Rodrigues¹,

Maffia²,

Dhingra³

et al. 2010

Trop. plant pathol.

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Sporulation of Alternaria solani can be scarce and is often reduced when the fungus is cultivated in vitro. A series of experiments were conducted to assess the effects of moisture, mycelial wounding, light quality and photoperiod, and culture media on conidial production. A procedure to induce sporulation based on mycelial wounding and dehydration was adapted and validated. Best results were obtained when fungal colonies were grown in V8 medium at 25 o C in the dark with agitation for seven days; the mycelium mass was ground, poured into potato dextrose agar (pH 6.5) in plates, and incubated at 25 ± 2 o C under near ultraviolet light and 12 h-photoperiod. The procedure was validated with 30 isolates of A. solani from different hosts, sampling locations, ages, and storage conditions. Conidial production, germination, and infectivity were quantified. Seventy-five percent of the isolates sporulated and the lowest germination rate was 68%. Inoculations of conidial suspension of all isolates resulted in lesions on tomato and potato plants. The effect of subculturing on A. solani sporulation was also assessed. After six subcultures, every seven days, there was no reduction in sporulation of colonies that were induced with the protocol. Key words: early blight, biphasic technique, subculture, infection frequency. RESUMO Produção in vitro de conídios de Alternaria solaniA esporulação de Alternaria solani in vitro pode ser escassa e tende a reduzir após sucessivas repicagens. Conduziram-se vários experimentos para avaliar o efeito da umidade, injúria da colônia, qualidade de luz e fotoperíodo, bem como do meio de cultura na produção de conídios. Adaptou-se a técnica bifásica para induzir esporulação, por meio de injúria de micélio e desidratação do meio de cultura. Obtiveram-se melhores resultados quando colônias cresceram em meio V8 a 25 o C, no escuro, sob agitação durante sete dias; a massa de micélio foi triturada e a suspensão depositada em meio BDA (pH 6,5) em placas de Petri, incubando-se a 25 ± 2 o C, sob luz negra com 12 h de fotoperíodo. Validou-se o protocolo para 30 isolados de A. solani distintos quanto ao hospedeiro, local de origem, idade e forma de armazenamento. Quantificaram-se a produção, germinação e infectividade de conídios. Dos 30 isolados, 75% esporularam e a germinação mínima de conídios foi de 68%. Todos os isolados foram patogênicos em seus respectivos hospedeiros. Avaliou-se, também, o efeito de repicagens sucessivas na esporulação. Todos os isolados produziram conídios após seis repicagens sucessivas. Palavras chave: pinta preta, técnica bifásica, subcultura, frequência de infecção.

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Section: The Adapted and Validated Protocol Allowed Efficient Inductimentioning

confidence: 56%

Section: The Adapted and Validated Protocol Allowed Efficient Inductimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

In vitro production of conidia of Alternaria solani

Rodrigues¹,

Maffia²,

Dhingra³

et al. 2010

Trop. plant pathol.

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“…Há um bom número de trabalhos indicando diferentes métodos de esporulação investigados, principalmente, entre as décadas de 50 e 80, como a utilização de luz ultravioleta (UV) (CHARLTON, 1953), luz fluorescente (LUKENS, 1960;DOUGLAS, 1972;STEVENSON;PENNYPACKER, 1988), injúria do micélio (LUDWIG; RICHARDSON; UNWIN, 1962), adição de substâncias ao meio de cultura, como carbonato de cálcio (SHAHIN; SHEPARD, 1979), tiamina, extrato de levedura (RATH; PADHI, 1975), potássio e zinco (RODIGIN, 1980). Apesar de relativamente antigas, muitas dessas referências se tornaram marcos no estudo dessas espécies e tiveram igual contribuição no conhecimento de seu crescimento e esporulação.…”

Section: Lista De Figurasunclassified

“…A luz UV, quando não provoca a morte celular ou mudanças genéticas permanentes, pode promover mudanças metabólicas como alteração na atividade enzimática, permeabilidade da membrana, transporte de íons ou no metabolismo do fosfato (POMPER; ATWOOD, 1955;POMPER, 1965 (LUKENS, 1960;LEACH, 1962;ZIMMER;McKEEN, 1969;DOUGLAS, 1972;FANCELLI;KIMATI, 1990;TEIXEIRA et al, 2001) A remoção do micélio aéreo dos isolados foi essencial para que houvesse grande produção de esporos, mas outros fatores estressantes e indutores da esporulação, como exposição das colônias à radiações UV e de microondas, também apresentaram resultados consideráveis.…”

Section: Efeito De Diferentes Estresses Da Colônia Na Esporulaçãounclassified

Crescimento e esporulação de >i<Alternaria dauci>/i< e >i<A. solani>/i< em meio de cultura

Pulz¹

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Growth and sporulation of Alternaria dauci e Alternaria solani in culture mediaAlternaria dauci and A. solani are two phytopathogenic fungus species known for difficult sporulation in culture media. This hampers artificial inoculations and, consequently, affects the selection process of carrot and tomato genotypes resistant to the diseases caused by these fungi. This study had the objective of verifying the influence of some factors applied during incubation on mycelia growth and sporulation of the two fungus species. Different culture media (BDA, oat and V8), temperature (15, 20, 25, 30 and 35 ºC), light wavelengths during incubation (yellow, blue, white, NUV, green, and red), stress types applied to the colony (scratching, UV, microwave irradiation, and temperature of 100 ºC) and photoperiods (light / dark, respectively, of 24 h / 0 h, 22 h / 2 h, 17 h / 7 h, 12 h / 12 h, 7 h / 17 h, 2 h / 22 h and 0 h / 24 h) were tested. Upon determination of the best factors, the method developed in this study was compared to the traditional procedure (BDA, 25 ºC, 12 h white / 12 h dark light and scratching of the colony), with different isolates of both species. Results indicated the V8-agar media and a temperature of 25 ºC as most favorable for growth and sporulation. The different wavelengths had a marked influence on sporulation and NUV was the most stimulating. All applied stress types induced sporulation, but best results were obtained with scratching of the colonies. The 12 h light / 12 h dark photoperiod stimulated sporulation most. In general, longer dark than light periods after the stress of the colony favored sporulation. The procedure developed in this study consisted of incubation in V8-agar media, a temperature of 25 ºC, scratching of the colony and a 12 h light / 12 h dark photoperiod. This process is clearly superior to the traditional method for growth and sporulation of both species.

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