In planta and in vitro interactions between Phomopsis (Diaporthe) isolates and sunflower
A.M. Pennisi, M.R. Abenavoli, B. Maimone, L. Di Diohttps://doi.org/10.17221/10524-PPSCitation:Pennisi A.M., Abenavoli M.R., Maimone B., Di Dio L. (2002): In planta and in vitro interactions between Phomopsis (Diaporthe) isolates and sunflower. Plant Protect. Sci., 38: 461-465.
In this study, we determined the amount of H2O2 released by sunflower callus cultures challenged by both crude hyphal wall extracts and culture filtrates of 26 Phomopsis isolates from sunflower of worldwide origin (Argentina, France, Italy, Yugoslavia, Rumania). The amount of H2O2 released by callus cultures and the production time-course response, however, did not correlate with both the amount of electrolytes released by sunflower leaf disks treated with crude culture filtrates and the results of pathogenicity tests on sunflower seedlings. Only few isolates induced a time-course response indicative of an oxidative burst. This would suggest that elicitors extracted from hyphal walls are not involved in this host-pathogen recognition system and toxic metabolites produced by Phomopsis in liquid cultures are not pathogenicity factors.Keywords:
Phomopsis helianthi; Diaporthe helianthi; Phomopsis stem canker; sunower; pathogenicity; reactive oxygen species; hydrogen peroxide