Mycobiome Profiling of Asymptomatic and Symptomatic Welsh Onion Naturally Infected by the Leaf Blight Pathogens in Taiwan

Mycobiome Profiling of Asymptomatic and Symptomatic Welsh Onion Naturally Infected by the Leaf Blight Pathogens in Taiwan

Himanshi Jayasinghe1, Shan-Hua Yang2, Po-Yu Liu3, Stephen Knobloch4, Hao-Xun Chang1 and Hiran A. Ariyawansa1*

1Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan

2Institute of Fisheries Science, National Taiwan University, Taipei, Taiwan

3School of Medicine, College of Medicine, National Sun Yat-sen University, Kaohsiung, Taiwan

4Department of Food Technology, Fulda University of Applied Sciences, Fulda, Germany


In recent years, Welsh onion cultivation in Taiwan has been severely threatened by leaf blight diseases greatly affecting their yield and quality. Interestingly, limited studies exist on the Welsh onion microbiome especially, since how it changes during a pathogenic attack has not been well understood. Characterizing the microbial communities associated with foliar diseases is a key approach to understanding the interactions between the pathogens and the members of the microbial communities involved in the disease process and the role of resident microbes against the pathogens. Thus, in the present study, the mycobiome of phyllosphere and rhizosphere of asymptomatic and symptomatic Welsh onion naturally infected by leaf blight pathogens was explored by amplicon sequencing targeting Internal Transcribed Spacer (ITS) region of rRNA genes. The results revealed a dominance of Ascomycota and Basidiomycota in both the phyllosphere and rhizosphere. Fungal genera such as Chaetomium, Hannaella and Itersonilia were abundant in the phyllosphere of asymptomatic plants. Being enriched in the symptomatic phyllosphere, the fungus Stemphylium was identified as the most probable pathogenic group causing the leaf blight symptoms. An increase of genera such as Athelia, Colletotrichum and Aspergillus was observed in the diseased rhizosphere, while Fusarium, Mortierella and Trichoderma were enriched in the healthy rhizosphere. Alpha diversity analysis indicated a significant increase in species richness in the diseased phyllosphere and a significant increase in Shannon diversity in the healthy rhizosphere. These results provide the basis for future studies, investigating the development of potential biological control strategies against leaf blight diseases of Welsh onion.