An Efficient Technique for Inducing Profuse Sporulation of<i>Alternaria</i>Species

Shahin, Elias A.; Shepard, James F.

doi:10.1094/phyto-69-618

Cited by 68 publications

(34 citation statements)

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“…Spore production requires special conditions such as mycelial wounding or the transfer of culture pieces onto a minimal medium or filter paper followed by exposure to harsh conditions (Lukens and Horsfall 1968;Barksdale 1969;Shahin and Shepard 1979). Efficient sporulation can be induced by exposing cultures under diurnal light in a partially opened culture dish, after removal of aerial mycelia (Barksdale 1969).…”

Section: Inoculum Productionmentioning

confidence: 99%

Tomato early blight (Alternaria solani): the pathogen, genetics, and breeding for resistance

Chaerani¹,

Voorrips²

2006

J Gen Plant Pathol

228

143

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Alternaria solani causes diseases on foliage (early blight), basal stems of seedlings (collar rot), stems of adult plants (stem lesions), and fruits (fruit rot) of tomato. Early blight is the most destructive of these diseases and hence receives considerable attention in breeding. For over 60 years, breeding for early blight resistance has been practiced, but the development of cultivars with high levels of resistance has been hampered by the lack of sources of strong resistance in the cultivated tomato and by the quantitative expression and polygenic inheritance of the resistance. In some accessions of wild species, high levels of early blight resistance have been found, but breeding lines still have unfavorable horticultural traits from the donor parent. Recently, the first linkage maps with loci controlling early blight resistance have been developed based on interspecific crosses. These maps may facilitate markerassisted selection. This overview presents the current knowledge about the A. solani-tomato complex with respect to its biology, genetics, and breeding.

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Section: Inoculum Productionmentioning

confidence: 99%

Tomato early blight (Alternaria solani): the pathogen, genetics, and breeding for resistance

Chaerani¹,

Voorrips²

2006

J Gen Plant Pathol

228

143

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“…Considerable attention has been directed towards improving conidial production of Alternaria species by using unfavorable conditions for vegetative growth (Rotem & Bashi, 1969;Shahin & Shepard, 1979;Walker, 1980;Ávila et al, 2000;Vieira, 2004). Three major factors that influence sporulation in vitro are commonly manipulated: nutrition, light spectrum, and temperature.…”

Section: Introductionmentioning

confidence: 99%

“…(Miller, 1955;Shahin & Shepard, 1979;Dalla Pria et al, 1997;Ávila et al, 2000;Vieira, 2004). Commonly, calcium carbonate (CaCO 3 ) is also added to increase sporulation (Miller, 1955;Shahin & Shepard, 1979), but it is unknown whether its effect is due to the change in pH or due to calcium supplementation.…”

Section: Introductionmentioning

confidence: 99%

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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“…All the isolates were subjected to pathogenicity tests (isolation and reisolation) as described by Osiru et al [19] with modifications in order to confirm that the causal agent was A. bataticola. The isolates were grown for sporulation as described by Shahin & Shepard [20]. Spore suspensions for each isolate were then prepared and adjusted to 5 X 10 4 conidia per milliliter.…”

Section: Sample Collectionmentioning

confidence: 99%

Assessing the Genetic Diversity of <i>Alternaria Bataticola</i> in South Africa using Molecular Markers

Chalwe

Adebola

Pillay

2017

AJAS

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Sweetpotato (Ipomoea batatas) an economically important food crop is affected by viral and fungal diseases. The most important fungal disease is Alternaria blight caused by Alternaria bataticola. Alternaria blight can be controlled using fungicides and cultural practices in the short-term. A sustainable control measure is the development of resistant sweetpotato cultivars. A prerequisite to this approach is the knowledge of the genetic diversity of this fungal pathogen. This study assessed the genetic diversity of A. bataticola in South Africa using RAPD analysis, DNA sequencing and secondary structures of the ITS2 region. Samples were collected from 25 different localities and the pathogen was identified in the laboratory. Both RAPD and ITS2 sequence data showed that there is high levels of genetic diversity among the isolates of A. bataticola. Although the dendrograms generated from the RAPD and ITS2 sequences clustered some isolates according to their place of origin, the majority of isolates did not group according to their geographic origins. The predicted ITS2 secondary structure models were variable ranging from simple to complex. The unique secondary structures of each isolate can be used to identify and distinguish each of the isolates used in this study.Â Â

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An Efficient Technique for Inducing Profuse Sporulation ofAlternariaSpecies

Cited by 68 publications

References 0 publications

Tomato early blight (Alternaria solani): the pathogen, genetics, and breeding for resistance

Tomato early blight (Alternaria solani): the pathogen, genetics, and breeding for resistance

In vitro production of conidia of Alternaria solani

Assessing the Genetic Diversity of <i>Alternaria Bataticola</i> in South Africa using Molecular Markers

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