Production, purification and separation of phytotoxins from Exserohilum turcicum isolates of Kenyan, German and Austrian origin

Abstract

The study was carried out to compare production, purification and identity of phytotoxins from Exserohilum turcicum isolates of Kenyan, German and Austrian origin. Phytotoxins were extracted from maize leaves inoculated with the pathogen and liquid media seeded with the pathogen isolates. Detection of the phytotoxins was done by checking on inhibition of chlorophyll synthesis using the detached leaf bioassay technique. Thin layer chromatography, high performance liquid chromatography and sephadex columns were used to separate, purify and identify the phytotoxins. Of the 86 isolates used in the study, 48.3% were found to produce phytotoxins either in the liquid media or from the inoculated leaves. The study showed that, a number of phytotoxins including monocerin are produced as indicated by the several peaks and retention times. Maize plants inoculated with the pathogen produced more phytotoxins than the liquid media seeded with the pathogen and each of them had mean lesion sizes of26 mnr' and 14 mm'', respectively. E. turcicum has a high variability in production of different types and amounts of phytotoxins. Maize leaves inoculated with E. turcicum produce more phytotoxins and detached leaf bioassay is a reliable technique in the preliminary detection ofphytotoxins.