Abstract

Alternaria alternata (Fr.) Keissler, the causal agent of Alternariosis of groundnut seeds (Arachis hypogaea L.) was toxigenic when cultured on various laboratory media. The cell free extract or culture filtrate induced severe chlorosis and necrosis on leaves, inhibition of root and shoot growth of germinating seeds and wilting of seedlings. A phytotoxin was isolated both from cell free extract/culture filtrate and infected tissues, purified and identified as tenuazonic acid, by using thin layer chromatography, ultra violet and infra red spectral analysis. Toxicity was monitored with standard bioassay techniques. The results show patho-physiological significance of tenuazonic acid in disease syndrome.

Key words: Alternaria alternata, groundnut, alternariosis, tenuazonic acid.