Preliminary report on the study of postharvest fruit rot bacteria and yeasts in Lanzhou Lily (Lilium davidii var. unicolor) in China

Fruit rot is one of the most important factors affecting the postharvest quality and shelf life of Lanzhou Lily fruits. The aims of this study were to characterize different isolates from Lanzhou Lily using morphological and molecular approaches and to test their pathogenicity in Lanzhou Lily fruit. Different isolates were collected from decayed Lanzhou Lily fruits in Lanzhou in Gansu Province in China during 2016 and 2017. In total, four isolates were obtained and identified based on their DNA sequences of the 16S rDNA and 26S rDNA genes in combination with the morphological characteristics of the cultures and sporulation. Of the four isolates, one was identified as Bacillus safensis, one was Stenotrophomonas maltophilia and the other two isolates were Metschnikowia pulcherrima. The pathogenicity tests showed that all four isolates were pathogenic in Lanzhou Lily fruit. Previously Fusarium tricinctum has been reported to be the primary cause of fruit rot in Lanzhou Lily throughout the world. Our report is the first to show results that indicate that B. safensis, S. maltophilia and M. pulcherrima are pathogenic in Lanzhou Lily in China. This is the first report on the bacteria and yeast that infect Lanzhou Lily fruits.