Nicotiana tabacum agglutinin expression in response to different biotic challengers

Abstract

The induction of the Nicotiana tabacum agglutinin or NICTABA was studied in tobacco leaves infected with a necrotrophic pathogen (Botrytis cinerea) and compared to folivory by several pest arthropods. It was clearly demonstrated that B. cinerea does not induce NICTABA expression, while arthropod herbivory stimulates a strong NICTABA accumulation. In order to further investigate the importance of feeding style for inducing lectin expression, tobacco plants were challenged with several arthropods that use different feeding guilds. It was shown that chewing caterpillars (Spodoptera littoralis and Manduca sexta) and cell-content-feeding spider mites (Tetranychus urticae) induce NICTABA expression, while infestation with phloem-feeding herbivores such as aphids and whiteflies (Myzus nicotianae and Trialeurodes vaporariorum) does not result in NICTABA accumulation. The presence of elicitors for NICTABA induction in oral secretions, salivary extracts or excrement extracts from S. littoralis larvae, was investigated through repeated application of different secretions to punctured wounds and analysis of lectin expression. However, none of the treatments could induce the accumulation of NICTABA as did herbivory