conference schedule and program with abstracts - Horticulture ...

P-98
Investigation of the interaction of Elsinoë ampelina with Vitis vinifera
A. Kono, M. Nakano, K. Suzaki, A. Sato, N. Mitani, Y. Ban
Grape and Persimmon Research Station, National Institute of Fruit Tree Science, National
Agricultural and Food Research Organization (NARO), 301-2 Akitsu, Higashi-Hiroshima,
Hiroshima, Japan
Corresponding author: akono@affrc.go.jp
Grapevine anthracnose is a disease of European origin that reduces the quality and the quantity
of the crop. The causal fungus is Elsinoë ampelina (de Bary) Shear. Previously, we sought the
optimum conditions for a simple method to stably generate conidia, and found a high negative
correlation between the colony density on potato dextrose agar (PDA) medium and the number
of resultant conidia. (Kono et al., 2009). The conidia produced by this method were pathogenic
to susceptible Vitis vinifera. Two days after the inoculation of the conidial suspension, small
collapse on the surface of the leaves were observed. The color of the collapsed area was almost
green, which is similar to that of the healthy part of the leaves. Visible brownish lesions were
formed after four to five days post-inoculation. However, the green collapsed cells were
observed in the peripheral area of the brownish lesions even after seven days post-inoculation,
suggesting that the fungus actively invaded in the healthy cells without inducing any defense
responses. One of the important processes of defense responses is the hypersensitive response
(HR), which is a localized self-induced cell death at the site of infection. HR inhibits pathogen
growth by the release of toxic compounds, and also leads to the activation of numerous other
defense-related genes. We used trypan blue staining in order to stain both the fungal cells and the
site of the HR. After the staining, deeply stained cells of the grapevine were observed in the
central part of the lesions. However, bluish hyphae were observed in the peripheral area of the
lesions surrounded by the leaf cells that were not stained with trypan blue, which suggested that
the surrounding cells of the hyphae did not show the HR. These observations showed that the
mycelia of E. ampelina actively invaded into the living V. vinifera cells without inducing the HR,
suggesting that the absence of the HR in V. vinifera might be the cause of the susceptibility to E.
ampelina.
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