Location: Vegetable Crops ResearchTitle: Expression of ß-1,3-glucanase and ß-1,4-glucanase in two potato cultivars following challenge by the fungal pathogen Alternaria solani) Author
Submitted to: Phytoparasitica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2010
Publication Date: 11/1/2011
Citation: Shahbazi, H., Aminian, H., Sahebani, N., Halterman, D.A. 2011. Expression of ß-1,3-glucanase and ß-1,4-glucanase in two potato cultivars following challenge by the fungal pathogen Alternaria solani. Phytoparasitica. 39(5):455-460. Interpretive Summary: We have previously identified potato cultivars that differ significantly in resistance to the early blight pathogen Alternaria solani. We found that levels of the pathogenesis-related proteins ß-1,3-glucanase and ß-1,4-glucanase were significantly induced after inoculation with A. solani, regardless of the resistance type. We also found that both enzyme levels were significantly higher in the resistant cultivar when compared to the susceptible cultivar suggesting an important role in resistance. Furthermore, we found that even in the absence of the pathogen the more resistant potato cultivar had higher levels of glucanse. We propose that testing glucanase levels in potato cultivars may help predict resistance in plants with unknown resistance capabilities. Our findings will impact potato breeders by providing methodologies that can be used to screen and select germplasm containing resistance to Alternaria solani.
Technical Abstract: Early blight of potato, caused by Alternaria solani, is a ubiquitous disease in many countries around the world. We have previously found that variation in resistance phenotypes exist between two different Iranian cultivars of potato. Cultivar ‘Diamond’ is more resistant to multiple isolates of A. solani when compared to cultivar ‘Granula’. Furthermore we have found that different pathogen isolates have varying degrees of aggressiveness. In this study, we have monitored the activities of pathogen-related proteins in ‘Diamond’ and ‘Granula’ in response to two isolates of A. solani with different degrees of aggressiveness. ß-1,3-glucanase and ß-1,4-glucanase activities were recorded in healthy and diseased leaves of potatoes 1 to 10 days and 2 to 8 days post inoculation, respectively. Their activities were found to be higher in diseased leaves when compared to those of healthy leaves. Our data suggests that significantly lower activities of these enzymes in potato could be related to a lower degree of resistance.