Studies on Endophytes Associated with Medicinally Important Saraca asoca (Roxb.) Willd and their Antagonistic Activity against Phytophthora colocasiae

Abstract

Taro (Colocasia esculenta (L.) Schott), a clonally propagated aroid grown largely in humid tropical areas of the world, is an important staple or subsistence crop for millions of people in developing countries. The oomycete Phytophthora colocasiae that cause taro leaf blight is the most devastating disease. The main purpose of the study was to evaluate the antagonistic activity of endophytic bacteria and fungi associated with medicinally important Ashoka tree (Saraca asoca (Roxb.) Willd) against the pathogen P. colocasiae. The study involves the following phases such as isolation of endophytic bacteria and fungi, evaluation of antagonism against the pathogen using dual culture method and identification of potent endophytes. Among the 65 bacterial isolates tested, five viz., Bacillus pumilis, Bacillus safensis, Bacillus altitudinis, Bacillus amyloliquefaciens and Comamonas testosterone and 23 fungal isolates , two, viz., Nigrospora oryzae and Diaporthe sp. showed significantly high antagonistic effect (70-84%). This study shows that these endophytes can be utilized for developing a promising biocontrol agent against P. colocasiae in taro field.