Occurrence of Trichoconiella padwickii causing leaf blight on rice (Oryza sativa L.) in China and its phylogenetic analysis

Abstract

Rice (Oryza sativa L.) is a widely cultivated grain crop and a significant source of dietary carbohydrates. In 2019 and 2022, leaf blight disease was observed on rice in Jingzhou City, Hubei Province, China, that causal fungus was isolated from the disease lesions. Based on the morphological characteristics, sequences of internal transcribed spacer (ITS) of rDNA region and pathogenicity tests, it is identified as Alternaria padwickii (Ganguly) Ellis (1971), which is morphologically considered as Trichoconiella padwickii (Ganguly) Jain (1975). However, its molecular phylogeny is rare to know. According to the phylogenetic analysis of ITS, large-subunit ribosomal RNA (LSU) and RNA polymerase second largest subunit (RPB2) gene regions, the species should not belong to the genus Alternaria, which is the genus Trichoconiella in Pleosporaceae. This is the first report of leaf blight on rice caused by Trichoconiella padwickii in China and the determination of the phylogenetic position for Trichoconiella in Pleosporaceae.