0000000000582593
AUTHOR
Eva Bourdon
Acquired resistance triggered by elicitins in tobacco and other plants
Elicitins are a family of proteins excreted byPhytophthora spp. They exhibit high sequence homology but large net charge differences. They induce necrosis in tobacco plants which then become resistant to the tobacco pathogenPhytophthora parasitica var.nicotianae. In stem-treated plants, resistance was not restricted to the site of elicitin application, but could be demonstrated by petiole inoculation at all levels on the stem. Resistance was already maximum after two days and lasted for at least two weeks. It was effective not only towardsP. p. var.nicotianae infection, but also against the unrelated pathogenSclerotinia sclerotiorum. In contrast to dichloroisonicotinic acid, an artificial i…
Responses of tobacco to elicitins, proteins from Phytophthora spp. eliciting acquired resistance
With the exception of Phytophthora parasitica var. nicotianae (Ppn), the tobacco black-shank causing agent, Phytophthoras give rise to non-host interactions with tobacco. The resulting local hypersensitive response (HR) is accompanied by necrotic spots on the leaves at distance from the infection site [1]. Low molecular weight proteins are excreted by these Phytophthoras, both in planta and in vitro. They form a family of highly homologous holoproteins, called elicitins [2]. Tobacco plants treated with purified elicitins develop necrotic symptoms similar to those induced by the live fungus, and become resistant to further inoculation with Ppn [3]. Elicitin-treated tobacco represent an attra…