Morphological, pathological and molecular characterization of Phytophthora colocasiae responsible for taro leaf blight disease in India

The oomycetous fungus Phytophthora colocasiae that causes taro leaf blight is one of the most devastating diseases of taro and is widely distributed in India. A combination of morphological (colony morphology, mating type, pathogenicity, metalaxyl sensitivity) and molecular techniques (rDNA ITS sequencing and Start codon targeted polymorphism, ScoT analysis) was used to characterize 50 isolates of P. colocasiae obtained from different locations in India. Considerable differences in morphological parameters were observed. ScoT analysis revealed high polymorphism among the isolates. This study confirms that isolates of P. colocasiae are highly dynamic in nature and a considerable degree of diversity exists among them. A detailed knowledge of the morphological and molecular characters of P. colocasiae will help in developing suitable control strategies against the taro leaf blight disease.