First report of Colletotrichum fructicola causing leaf spots on Liriodendron chinense × tulipifera in China

Abstract

AbstractLiriodendron chinense × tulipifera is widely planted in China as an ornamental plant. In July 2018, a foliar disease, with an incidence of ~23% trees and ~ 45% leaves per individual tree infected, occurred on L. chinense × tulipifera on the campus of Nanjing Forestry University, Jiangsu Province, China. Symptoms were small brown to dark spots surrounded by a yellow halo initially, which enlarged and coalesced into regular or irregular brown necrotic lesions up to 8.5 ± 1.3 mm across. Fungi were isolated from the margins of the lesions. Three representative isolates (E3‐2, E3‐3 and E3‐4) were selected for phylogenetic analyses. One representative isolate E3‐2 was used for pathogenicity tests and morphological identification. The pathogenicity of isolate E3‐2 to L. chinense × tulipifera was confirmed on 1‐year‐old seedlings with lesions after 5 days. The phenotypic characteristics of the isolates were similar to those of Colletotrichum sp. (Glomerellaceae). Phylogenetic analyses using concatenated sequences of ITS, ACT, CHS, GADPH, CAL, SOD2 and TUB2 placed E3‐2, E3‐3 and E3‐4 in the clade of C. fructicola. Based on the morphological and phylogenetic studies, the isolates were identified as C. fructicola. This is the first report of C. fructicola causing L. chinense × tulipifera leaf spots in China.