Pyrosequencing reveals bacteria community associated with disease suppression after bio-organic fertilizer application in a banana orchard with serious Fusarium wilt disease. soil metagenome

Our previous work demonstrated that application of bio-organic fertilizer (BIO) to banana mono-culture orchard with serious Fusarium wilt disease hindering the banana production in China recently effectively controlled the soil borne disease. As bacteria are the most abundant and diverse groups of soil organisms responding for soil health, barcode pyrosequencing was employed to characterize the bacteria community in a deep insight composition to investigate how the soil bacteria community responded to BIO or other common composts application and to explore the possible mechanism of BIO for suppressing the banana Fusarium wilt disease in this study. After basal quality control, a total of 137,646 sequences and 9,388 operational taxonomic units (OTUs) were obtained from the 15 soil samples. Proteobacteria, Acidobacteria, Bacteroidetes, Gemmatimonadetes and Actinobacteria were the most frequent phyla and up to 75.3% of the total sequences. Compared to other soil samples, BIO treated soil showed highest abundant phyla of Gemmatimonadetes and Acidobacteria and lowest abundant phyla of Bacteroidetes, meanwhile it showed highest frequent genera of Gemmatimonas and Sphingomonas and lowest frequent genus of Ohtaekwangia. Both of correlation and RDA analysis showed that abundance of Gemmatimonas and Sphingomonas and content of soil TON and NH4-N was highest after BIO application and they all were positively correlated to the disease suppression. Combined all the results, BIO applied for 1-year reduced the Fusarium wilt disease incidence might be attributed to the fact that application of BIO containing Bacillus sp. induced soil general suppression by modulating the bacteria community and/or specific suppression by enrichment of Gemmatimonas and Sphingomonas.