glycosylation analysis of the avr9 effector of cladosporium fulvum, the fungal pathogen of solanum lycopersicum

Tomato (solanum lycopersicum) is one of the most important industrial crops, and is threated with various fungal pathogens like cladosporium fulvum. this fungus secretes avr9 effector into the apolast of tomato plants and is recognized by the tomato receptor-like protein cf-9. avr9-enoding gene is highly expressed during colonization of tomato apoplast. avr9 shares significant structural similarity with carboxypeptidase inhibitors, expecting to target host apoplastic proteases. so far, despite using sophisticated methodologies, no definitive avr9-interacting proteins have been successfully identified. one hypothesis is that glycosylation of avr9 might be crucial for interaction with host target(s). in this study, native proteins secreted by c. fulvum expressing avr9 were isolated. mass spectrometry analysis revealed that avr9 is n-glycosylated when secreted by c. fulvum, containing at least two n-acetylglucosamine (glcnac) and six mannose residues. the necrosis-inducing activity of glycosylated and non-glycosylated avr9 was determined and it was found that both caused a comparable cf-9-mediated hypersensitive response. this research represents a crucial advancement in the comprehension of the molecular interactions pertaining to the avr9 effector. nevertheless, more thorough examinations are requisite to completely elucidate its functionality and the implications of glycosylation. refining the experimental parameters and investigating additional potential interactors would presumably augment the reliability of the results.