Abstract:

To identify and analyze the species composition of pathogenic fungi isolated from diseased tobacco plants in the major tobacco-growing regions of Yunnan, newly infected tobacco plants and their tissues collected from these areas were used as test materials. Fungal identification was performed by ITS sequence PCR amplification and sequencing, yielding data for 39 fungal isolates. The obtained sequences were compared with those in the US National Center for Biotechnology Information (NCBI) database for homology analysis, and a phylogenetic tree was constructed using MEGA software. The results showed that 33 isolates could be identified to the species level, with high sequence homology to 12 known fungal species, whereas the remaining six isolates were identified only to the genus level. Among the isolates, 13 belonged to the genus Fusarium, accounting for 33% of the total. In total, 39 fungal isolates were recovered from diseased plants in Yunnan tobacco-growing areas; ITS analysis identified 12 species across 15 taxonomic groups, with Fusarium spp. representing the highest proportion and constituting the dominant group.

Key words: Yunnan, tobacco, pathogenic fungi, isolation, ITS sequence, identification, Fusarium