Pineapple-banana rotation greatly reduced the amount of Fusarium oxysporum through modulating soil microbial communities, especially in the fungal community structure. soil metagenome

Continuous cropping with banana results in a population build-up of specific plant pathogens such as Fusarium oxysporum f. sp. cubense race 4 (FOC) in soil, which causes the Fusarium wilt disease. Crop rotation has been an effective way of controlling different soil-borne diseases. The influence of two crop rotations of pineapple-banana and maize-banana on the population densities of FOC and subsequent soil microbial community structure was investigated in this study to understand the mechanism of how the rotation suppresses the Fusarium wilt disease. The results showed that the pineapple-banana rotated system was more effective than the maize-banana system in the reduction FOC and suppression of the Fusarium wilt disease. Then, we investigated the soil bacterial and fungal communities in a field experiment for a crop rotation of two years using deep pyrosequencing of the 16s RNA gene and the ITS region and found a lower relative abundance of FOC in the pineapple-banana rotated treatment than in the maize-banana rotated system. Greater differences in the fungal community membership and structure between the two rotation systems than in bacteria were observed via heat map and Venn analysis, indicating that the fungal community may play a more important role in the alteration of soil function. In the pineapple-banana rotated treatment, the enrichment of Acidobacteria, Planctomycetes, Chloroflexi phylum, Gp1, Gp2 and Burkholderia genus in bacteria and the significant differences in the main fungal phylum appeared to be the important microbe factors in the FOC decrease. In conclusion, this study characterized bacterial and fungal communities in soils with two different crop rotations and identified bacterial and fungal taxa that may be involved in the suppression of FOC.

香蕉连作会导致土壤中特定植物病原菌（如尖孢镰刀菌古巴专化型4号小种（Fusarium oxysporum f. sp. cubense race 4, FOC））的种群增殖，进而引发香蕉枯萎病。轮作是防控各类土传病害的有效途径。本研究选取菠萝-香蕉、玉米-香蕉两种轮作模式，探究其对土壤中FOC种群密度及后续土壤微生物群落结构的影响，以期揭示轮作抑制香蕉枯萎病的作用机制。研究结果表明，菠萝-香蕉轮作体系在降低FOC种群数量、抑制香蕉枯萎病方面的效果显著优于玉米-香蕉轮作体系。随后，本研究通过对16S rRNA基因及ITS区间进行深度焦磷酸测序，对为期两年的田间轮作试验中的土壤细菌、真菌群落展开分析，结果显示菠萝-香蕉轮作处理组的FOC相对丰度显著低于玉米-香蕉轮作体系。通过热图与维恩（Venn）分析可知，两种轮作体系间真菌群落组成与结构的差异显著大于细菌群落，提示真菌群落可能在土壤功能调控中发挥更为关键的作用。在菠萝-香蕉轮作处理组中，细菌群落中酸杆菌门（Acidobacteria）、浮霉菌门（Planctomycetes）、绿弯菌门（Chloroflexi）、Gp1类群、Gp2类群及伯克霍尔德菌属（Burkholderia）的富集，以及主要真菌门类的显著变化，均为FOC种群数量降低的关键微生物驱动因素。综上，本研究明确了两种不同轮作模式下土壤细菌与真菌群落的特征，并筛选出可能参与抑制FOC种群增殖的细菌与真菌类群。