Identification and Phylogenetic Analysis of Two Alternaria Species From Nelumbo nucifera in China

Abstract

Lotus (Nelumbo nucifera Gaertn.) is one of China's 10 most renowned commercially grown ornamental flowers. However, lotus is susceptible to various fungal infections, which can affect its rich nutritional composition and ornamental value. In 2023, 12 fungal cultures were isolated from lotus leaves in Liuzhou City, Guangxi Zhuang Autonomous Region, China. Based on the phylogenetic analyses using seven gene primers (ITS, GAPDH, TEF1, Alt a 1, RPB2, EndoPG and OPA10-2) and the phenotypic data, two species (five strains) in the section Alternaria were identified as A. melongenicola L. Zhao & J.X. Deng and A. nelumbiicola T.Y. Zhang. To the data, most of the Alternaria species found, including A. nelumbiicola, have been identified on the basis of host and morphological characteristics and no molecular data were available so far that support these earlier identifications. This study is the first worldwide report of A. melongenicola from lotus. It also provides the gene sequence information of A. nelumbiicola in GenBank, clarifies its phylogenetic position and distinguishes it from the previous classified morphospecies A. caudata which is phylogenetically considered as a synonym of A. alternata. In addition, pathogenicity test confirmed that these two Alternaria species are the causative agents of leaf spot of lotus.