Open AccessCharacterisation of a flavonoid ligand of the fungal protein Alt a 1
Author(s) -
María GarridoArandia,
Javier SilvaNavas,
Carmen Ramírez-Castillejo,
Nuria Cubells-Baeza,
Cristina GómezCasado,
Domingo Barber,
Juan C. del Pozo,
Pablo González Melendi,
Luis F. Pacios,
Araceli DíazPerales
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep33468
Subject(s) - ligand (biochemistry) , spore , fungus , alternaria alternata , biology , microbiology and biotechnology , flavonoid , reactive oxygen species , pathogen , biochemistry , chemistry , botany , receptor , antioxidant
Spores of pathogenic fungi are virtually ubiquitous and cause human disease and severe losses in crops. The endophytic fungi Alternaria species produce host-selective phytotoxins. Alt a 1 is a strongly allergenic protein found in A. alternata that causes severe asthma. Despite the well-established pathogenicity of Alt a 1, the molecular mechanisms underlying its action and physiological function remain largely unknown. To gain insight into the role played by this protein in the pathogenicity of the fungus, we studied production of Alt a 1 and its activity in spores. We found that Alt a 1 accumulates inside spores and that its release with a ligand is pH-dependent, with optimum production in the 5.0–6.5 interval. The Alt a 1 ligand was identified as a methylated flavonoid that inhibits plant root growth and detoxifies reactive oxygen species. We also found that Alt a 1 changes its oligomerization state depending on the pH of the surrounding medium and that these changes facilitate the release of the ligand. Based on these results, we propose that release of Alt a 1 should be a pathogenic target in approaches used to block plant defenses and consequently to favor fungal entry into the plant.