Anti-idiotypic antibodies can mimic the Phytophthora infestans elicitor responses in potato

LAXALT, AM; MADRID, EA; BELIGNI, MV; LAMATTINA, L

PHYSIOLOGICAL AND MOLECULAR PLANT PATHOLOGY

Año: 1998 vol. 53 p. 135 - 148

0885-5765

The initial infection process involving adhesion}recognition events between plants and fungal pathogens is essential for the establishment of pathogenesis. The basis of the speci®city between Phytophthora infestans and potato is not yet known. It could lie in the recognition between extracellular matrix and plasma membrane components of the penetrating structures of the fungus and host cells during the earliest stages of infection processes. We have used polyclonal antibodies (AZ and AC) obtained after immunizing rabbits with either 10( zoospores (Z) or germinating cysts (C) of P. infestans to detect putative fungal components located on the surface of invasive structures. AZ recognized several bands, while AC recognized three polypeptides of approximately 87, 73 and 45 kDa in western blots. Zoospore suspensions preincubated either with AZ or AC were unable to infect potato leaves. Since it was already known that some anti-idiotypic (anti-IT) antibodies may resemble the antigen, thus mimicking its structure, anti-IT antibodies (a-AZ and a-AC) were generated in mice and used as inducers on potato tuber discs. In northern blots a-AZ treatments increased 1±5-fold the glyceraldehyde-3-P dehydrogenase (GAPDH) and 1±8-fold the phenylalanine ammonia-lyase (PAL) transcript levels, while an increase of 1±8 and 1±7-fold for GAPDH and PAL, respectively, was observed when the inducer was a-AC. Both PAL and GAPDH transcript levels have previously been shown to be modulated by fungal and elicitor treatments. These results show that the anti-idiotypic antibodies are able to mimic the pathogen components, leading to the accumulation of transcripts related to defence responses in potato± P. infestans interaction.