In vitro production of conidia of Elsinoë ampelina, the causal fungus of grapevine anthracnose
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Anthracnose, caused by Elsinoë ampelina, is an important disease of grapevines in humid and warm production regions of the world. Colonies of E. ampelina grow slowly and rarely produce conidia on artificial media. To facilitate studies involving E. ampelina, our objective was to develop a method to induce significant conidial production of this fungus. In the present study, we induced the in vitro production of conidia of 10 Australian isolates by shake-incubation of mycelial fragments in rainwater under continuous light and darkness. Furthermore, seven Brazilian isolates were shake-incubated in rainwater and distilled water under continuous darkness. In both experiments cultures were shaken at 200-rpm and kept at room temperature (22–25 °C) for 7 days. Conidial production, germination, and severity of symptoms were quantified. Australian and Brazilian isolates produced different amounts of conidia. All Australian isolates sporulated in rainwater ranging from 4.20 × 103 to 5.91 × 106 conidia mL−1, with more than 90% conidial germination on water agar medium. All but one Brazilian isolate produced conidia in rainwater and distilled water, ranging from 7.50 × 103 to 8.22 × 106 conidia mL−1, with high germination percentages. Conidial suspensions from both Australian and Brazilian E. ampelina isolates caused typical anthracnose symptoms on grapevine leaves. This study describes an efficient method, using rainwater or distilled water associated with shaking, to induce the conidia production of E. ampelina.
KeywordsBlack spot Sporulation Rainwater Shaking Sphaceloma ampelinum Vitis vinifera
This research was financially supported by São Paulo Research Foundation – FAPESP (grant numbers 2013/24003-9, 2014/24472-1 and 2016/01508-6). We thank Andrew Taylor (Department of Agriculture and Food, Western Australia), Bob Emmett (RWE Horticultural Pathology Research, Victoria), David Oag and James Drinnan (Department of Agriculture and Fisheries, Queensland) for providing anthracnose samples. We wish to acknowledge the South Australian Research and Development Institute (SARDI) for providing resources and staff for technical assistance. Scholarship provided by FAPESP (grant number 2016/01508-6) for the first author during his eight months in Australia is gratefully acknowledged.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
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