Journal of Plant Pathology Archive

Abstract:

Curcuma wenyujin Y.H. Chen et C. Ling (Zingiberaceae family) is a plant whose rhizomes have been used since time immemorial in the traditional Chinese medicine to treat jaundice, dysmenorrhea, arthralgia, hematuria, and epilepsy (Dong et al., 2013). In 2013, severe symptoms of yellowing and wilt were observed on the edges of Curcuma leaves in Pan’an (Zhejiang province, China). Small pieces of tissues cut from diseased leaves were placed on potato dextrose agar (PDA), and incubated at 25°C in the dark. White my- celium grew from the margins of diseased tissues after two days, and a pure culture of a fungus (strain F13V-2) was ob- tained. Colonies grew up to about 54 mm in diameter within 33 h, and turned light green after 72 h. Conidia were green, smooth, ellipsoid, 3-4 × 2-3 μm in size (length/width ra- tio = 1.3 to 1.5). The internal transcribed spacer (ITS) region of rDNA was amplified with ITS1 and ITS4 primers and sequenced. Sequence analysis showed that the ITS sequence of F13V-2 (GenBank accession No. KF601689) was 100% identical to the ITS sequence of Trichoderma koningiopsis strain T-25 (KC884782.1). Pathogenicity tests showed that the fungus present on inoculated Curcuma leaves was identi- cal morphologically to that originally observed on diseased plants, which fulfilled Koch’s postulate. To our knowledge, T. koningiopsis has biological control potential and induces host resistance against pathogens (Samuels et al., 2006). However this is the first report of leaf blight disease of C. wenyujin caused by T. koningiopsis in China.