| Banana production has been severely hindered by the long-term continuous crop due to economic stability. Fusarium wilt disease, caused by the Fusarium oxysporum f. sp.cubense (FOC), is one of the most destructive diseases in the world. Among the management control of Fusarium wilt, rational crop rotation has been an effective and stable means of prevention of the disease. In this study, eggplant-banana rotation system was used to investigate the effect of cultivating eggplants combining bio-organic fertilizer on soil microflora in banana continuous cropping orchard with serious Fusarium wilt diseases by residue pot and field experiment using the plate count method, denaturing gradient gel electrophoresis (PCR-DGGE) technique, real time PCR and high-throughput sequencing method. Characterization of microbial community in naturally soils to alleviate the banana Fusarium wilt disease is the important basis for overcoming the biological obstacles of banana continuous cropping. Eggplant-banana rotation system combining bioorganic fertilizer was used to investigate the effect of the disease incidence and yield.The residue of leaching agent and root exudates have been to analyzed on pathogens of bananan. The main results are as follows:The effects of application of bio-organic fertilizer on the number of culturable Fusarium oxysporum, fungi and bacteria for both continuous cropping system and rotation with eggplant system of banan were not extremely significant compared with those of organic fertilizer treatment. However, compared with continuous cropping banana, rotation with eggplant of banan significantly reduced the number of culturable Fusarium oxysporum, the number of culturable Fusarium oxysporum decreased from 104 cfu·g-1 to 103 cfu·g-1 in dry soils. Soil pH, organic matter and available N, P and K contents increased under bio-organic fertilizer treatment. The ratio of bacteria to fungi (B/F) in eggplant-banana rotation system was significantly higher in bio-organic fertilizer than that in organic fertilizer treatment.Based on DGGE results, soil bacterial structure was obviously altered after eggplant-banana rotation with bio-organic fertilizer treatment for a year, and then soil bacterial richness, stability and diversity index increased compared with the control (continuous cropping of banana).Real-Time PCR results showed that the ratio of bacteria to fungi (B/F) in both the total number of bacteria or fungi was significantly higher in other treatment, MiSeq high-throughput sequencing results showed that eggplant rotation combining organic fertilizers (EBF) are significantly improved whether bacteria or fungi in the microbe abundance (Chao, ACE) among the treatment. Compared to banana continune cropining,The mean relative abundance of gemmatimonas were significantly higher in the first season by eggplant-banana rotation system while Gp6 was significantly increased in the second season.Residues extracts of banana will promote Fusarium oxysporum spore germination,and significantly higher than the control treatment. eggplant root exudates inhibiting the mycelial growth and sporing germination, while the control and banana continune crop treatment promote it. Plant height, stem diameter and leaf area were significantly increased When adding amount of eggplant residues of 2% and 3% to soil . The banana disease incidence was lowest When adding amount of eggplant residues of 2% to soil. The number of cultural Fusarium oxysporum, bacteria, fungi were significantly higher than that of banana residue add or CK processing.Real-time PCR results showed that both total number of bacteria and fungi were significantly higher than that of banana and control treatment in 2 season pot experiment whatever bulk or root soil.Compared to eggplant-bananan combining organic fertilizer((EOF) application and bananan continue croping control (BOF),the BIO application showed significant decreased in disease incidence and increased in fruit yield. Application of bio-organic fertilizer also improve the pH of the soil, increase in organic matter, nitrogen and available phosphorus content. The number of cultural Fusarium oxysporum and fungi markedly lower than those of banana cropping treatments in different plant system. In addition, the ratio of bacterio to fungi (B/F)and the ratio of actinomyces to fungi(A/F) were significantly higher than that of banana cropping treatments. Real-time PCR results showed that the number of copies of total bacteria is highest among the treatment. Next-generation sequencing of the 16S rRNA genes and ITS sequences using the MiSeq platform showed that the abundance of Basidiomycota, Dokdonella and Rhodanobacter significantly increased, while the abundance of Ascomycota and Fusarium was significantly decreased in the egglant-bananan rotation combining bio-organic fertilazer treatment compared with the control. Spearman correlation analysis showed that disease incidence were positively correlated with the abundance of Fusarium, which were negatively correlated with the soil pH ,the contents of organic matter, available nitrogen, available phosphorus and dominant bacteria genus Dokdonella.In conclusion, the rotation of eggplant with banana could effectively improve soil microflora, and plus bio-organic fertilizer application even had a better effect. |
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