Syringicin, a new alpha-elicitin from an isolate of Phytophthora syringae,pathogenic to citrus fruit

The primary structure of syringicin (syr), a new acidic alpha -elicitin, is olated from culture filtrates of Phytophthora syringae, causal agent of cit rus fruit rot, has been determined using a combined approch based on Edman degradation and MALDI-MS (TTCTT TQQTA AYVAL VSILS DSSFN QCATD SGYSM LTATA L PTTA QYKLM CASTA CKTMI TKIVS LNAPD CELTV PTSGL VLNVY SYANG FSSTC ASL). Syr has 98 amino acids with a MF of 10194.6 +/- 0.2, which was determined by el ectrospray ionisation-mass spectrometry (ES-MS) and in agreement with three disulphide bridges, located between Cys3-Cys71, Cys27-Cys56 and Cys51-Cys9 5. Syr induces a hypersensitive response and electrolyte leakage in tobacco . These are characteristic elicitor properties of the group and in agreemen t with the molecular mechanism recently proposed for this kind of protein. Finally, its possible applications in biological agriculture and biomedicin e are briefly discussed. (C) 2001 Elsevier Science Ltd. All rights reserved .