Journal of Plant Pathology & Microbiology

Abstract

Serine Exoproteinases Secreted by the Pathogenic Fungi of Alternaria Genus

Tatiana A Valueva, Natalia N Kudryavtseva, Alexis V Sofyin, Boris Ts Zaitchik, Marina A Pobedinskaya, Lyudmila Yu Kokaeva and Sergey N Elansky

Fungi of different species of the Alternaria genus isolated from potato or tomato plants in several Russian regions excreted proteolytic enzymes during the growth in the medium containing thermostable proteins of pea and carrot. The growing of fungi in such medium can be considered as a model system for studying the infection process. It has been shown increased production of proteolytic enzymes that included serine proteases belonging to the subtilisin and trypsin families. In most isolates, the proteolytic enzymes production has been observed during the exponential phase of growth. The data obtained demonstrated that the exoproteinase activity depended on the natures of both the isolate and its host plant, but it was defined by the isolate's genotype predominantly. The data also clearly demonstrated a phenomenon of exceeding of the exoprotease activity, especially trypsin-like, in the tomato isolates in comparison with that in the potato isolates. They indirectly indicate the possibility of pathogenic specialization of Alternaria spp. in the Solanaceae that is in accordance with the existence of intra- and inter-specific variations in species of Alternaria.