烟草赤星病与野火病复合侵染烟叶叶际微生物群落结构与多样性OA

[Background]This study aims to elucidate the characteristics of microbial community structure and diversity in the phyllosphere of tobacco leaves co-infected with brown spot and wildfire diseases.[Methods]Asymptomatic tissues and diseased tissues were collected from typical infected tobacco leaves at disease severity grades 1,3,5,and 7.Illumina high-throughput sequencing was employed to analyze the fungal and bacterial community structures associated with asymptomatic and diseased leaf tissues.[Results]Significant differences in fungal and bacterial community diversity were observed between asymptomatic and diseased tobacco leaf tissues across different disease severity levels.Fungal diversity was higher in asymptomatic leaf tissues,whereas diseased tissues exhibited reduced fungal diversity.At the genus level,the dominant fungal genera in diseased tissues included Alternaria and Filobasidium.The relative abundance of Alternaria in leaves with disease grades 1,3,5,and 7 was 53.37％,61.72％,63.12％,and 82.67％,respectively.In contrast,asymptomatic leaf tissues were mainly dominated by Filobasidium and Cladosporium,with relative abundances ranging from 6.41％to 39.07％and 5.50％to 17.04％,respectively.The dominant bacterial genera in diseased leaf tissues were Pantoea and Pseudomonas.The relative abundance of Pseudomonas in leaves with disease grades 1,3,5,and 7 was 18.01％,55.15％,38.71％,and 30.90％,respectively.Asymptomatic leaf tissues were primarily dominated by Pantoea,with relative abundances ranging from 16.69％to 56.43％.Furthermore,the relative abundances of Pseudomonas,Xerobacter,and Xanthomonas were significantly higher in diseased leaf tissues than in asymptomatic tissues.[Conclusion]This study reveals distinct phyllosphere microbial characteristics associated with the co-infection of brown spot and wildfire diseases in tobacco leaves,providing a reference for understanding the mechanisms underlying the combined occurrence of these two diseases.