石灰碳铵熏蒸联合生物有机肥施用对香蕉土壤真菌群落的影响

Effects of lime and ammonium carbonate fumigation coupled with bio-organic fertilizer application on banana fungal community

土壤真菌群落的调控是防治香蕉枯萎病的关键,为探明石灰碳铵熏蒸联合生物有机肥施用调控香蕉土壤真菌群落防控香蕉枯萎病的机制,通过田间试验,研究不熏蒸+有机肥(OF)、不熏蒸+生物有机肥(BF)、石灰碳铵熏蒸+有机肥(LAOF)和石灰碳铵熏蒸+生物有机肥(LABF)的施用对香蕉土壤真菌群落的影响.结果显示:相比于OF处理,LAOF和LABF的真菌群落丰富度和多样性均降低,其中,LABF的丰富度和多样性均显著低于LAOF;土壤熏蒸和施肥处理为驱动真菌群落组成改变的影响因子,且熏蒸对其产生了更重要的影响.网络分析结果表明,熏蒸+施肥处理使土壤真菌网络结构由以有害微生物为主导向以有益微生物主导的方向转变;FUNGuild功能注释结果表明,熏蒸处理显著降低了土壤中植物病原菌和腐生真菌的相对丰度,增加了土壤中的外生菌根等有益真菌的相对丰度.另外,相比于LAOF处理,外生菌根真菌在LABF中显著富集;对网络中的关键节点分析发现,OTU_1(Tuber)、OTU_14(Cordycipitaceae_unidentified)和OTU_21(Simplicillium)在熏蒸处理中显著富集,这些真菌的相对丰度与发病率呈极显著负相关,且在熏蒸后施生物有机肥处理中的相对丰度显著高于熏蒸后施有机肥处理.本研究表明石灰碳铵熏蒸+生物有机肥的施用显著降低了土壤真菌群落的丰富度和多样性,但激发了土壤中具有抑菌潜力的关键微生物,使其向有利于香蕉健康生长的方向发展.

Regulation of the soil fungal flora is critical for banana wilt prevention and control.This study aimed to investigate the effect of lime-ammonium fumigation coupled with bio-organic fertilizer application on soil fungal flora in a field experiment.This study focused on the effects of organic fertilizer(OF),bio-organic fertilizer(BF),lime,and ammonium carbonate fumigation coupled with organic fertilizer(LAOF),and lime-ammonium fumigation coupled with bio-organic fertilizer application(LABF)on banana fungal communities using high-throughput sequencing methods based on field experiments.The alpha diversity analysis of soil fungi showed that fumigation combined with different fertilizer applications significantly reduced richness compared with organic and bio-organic fertilizers.The diversity of LABF was significantly lower than that of BF,while there was no significant difference between the LAOF and OF.LABF showed significantly higher richness and diversity than LAOF.Principal coordinate analysis(PCoA)and multivariate regression tree analysis(MRT)of fungal communities based on the Bray-Curtis distance metric showed that soil fumigation and fertilization were influential factors driving the change in fungal community composition.Still,fumigation has a decisive impact on community composition.Moreover,the microbial community structure of LABF was significantly different from that of other treatments,and the community composition differences of LABF and LAOF were greater than those of BF and OF.Network structure analysis results showed that fumigation coupled with different fertilization treatments simplified the network structure of soil fungi.The network of harmful microorganisms in the network structure before fumigation is more complicated,while the network of beneficial microorganisms in the network structure after fumigation is more complicated.This indicated that fumigation changed the microbial network structure from harmful microorganisms to beneficial microorganisms.FUNGuild functional annotation results showed that fumigation significantly reduced the relative abundance of plant pathogens and saprotrophic fungi in the soil and increased the relative abundance of beneficial fungi such as ectomycorrhizal fungi.In addition,compared with LAOF,ectomycorrhizal fungi were significantly enriched in the LABF treatment.Analysis of key nodes in the network revealed that the abundance of OTU_4(Fusarium)was significantly reduced in fumigation combined with different fertilizers compared with non-fumigation.The relative abundance in LABF was significantly lower than that in LAOF.Spearman correlation analysis showed that there was a significant positive correlation between OTU_4 and disease incidence.OTU_1(Tuber),OTU_14(Cordycipitaceae_unidentified),and OTU_21(Simplicillium)were significantly enriched in LAOF and LABF,and the relative abundance of these microbes was also significantly and negatively correlated with disease incidence.In conclusion,lime and ammonium fumigation coupled with the application of bio-organic fertilizer reduced the richness and diversity of soil fungi.It enriched the key taxa with disease suppression potential,resulting in a healthy and beneficial soil fungal community.