Structure of Endophytes in the Root, Stem, and Leaf Tissues of Sweetpotato and Their Response to Sweetpotato Scab Disease Caused by Elsinoë batatas

Endophytes are symbiotic microbes that are mutually beneficial to the plant host and whose number and diversity affect the strength of plant resistance to stresses. The infection of sweetpotato with the scab pathogen can lead to yield losses. However, little is known about how the endophytic flora in sweetpotato respond to scab pathogen infection. This study used high-throughput amplicon sequencing with Illumina's MiSeq PE300 platform ITS and the 16SrRNA gene to analyze the composition and distribution of endophytic flora in the roots, stems, and leaves of sweetpotato plants infected with scab disease and those of healthy plants. The dominant endophytic fungi in sweetpotato were Ascomycota, while the dominant endophytic bacteria were Proteobacteria. The diversity of endophytic fungi in the healthy plants followed a root > stem > leaf trend, while an opposite trend was observed in the infected plants. The diversity pattern of endophytic bacterial flora showed a root > stem > leaf trend in both healthy and infected plants. The scab pathogen Elsinoe was classified under OTU87 and was enriched in the leaves and stems of the infected plants. OTU87 was negatively correlated with Acaulospora and positively correlated with eight other fungal taxa, including Cladosporium.Future research should focus on exploring potential biocontrol fungal resources for sweetpotato scab.