Association of soil fungal community composition with incidence of Fusarium wilt of banana in Malaysia

Banana (Musa spp.), an important food crop in many parts of the world, is threatened by a deadly wilt disease caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (TR4). Increasing evidence indicates that plant actively recruits beneficial microbes in the rhizosphere to suppress soil-borne pathogens. Hence, studies on the composition and diversity of the root-associated microbial communities are important for banana health. Research on beneficial microbial communities has focused on bacteria, although fungi can also influence soil-borne disease. Here, high-throughput sequencing targeting the fungal internal transcribed spacer (ITS) was employed to systematically characterize the difference in the soil fungal community associated with Fusarium wilt (FW) of banana. The community structure of fungi in the healthy and TR4-infected rhizospheres was significantly different compared with that of bulk soil within the same farm. The rhizosphere soils of infected plants exhibited higher richness and diversity compared with healthy plants, with significant abundance of Fusarium genus at 14%. In the healthy rhizosphere soil, Penicillium spp. were more abundant at 7% and positively correlated with magnesium. This study produced a detailed description of fungal community structure in healthy and TR4-infected banana soils in Malaysia and identified candidate biomarker taxa that may be associated with FW disease promotion and suppression. The findings also expand the global inventory of fungal communities associated with the components of asymptomatic and symptomatic banana plants infected by TR4.

香蕉（芭蕉属Musa spp.）作为全球多地重要粮食作物，正受到由尖孢镰刀菌古巴专化型热带生理小种4号（Fusarium oxysporum f. sp. cubense Tropical Race 4, TR4）引发的毁灭性枯萎病的威胁。越来越多研究证据表明，植物可主动招募根际有益微生物以抑制土传病原菌。因此，解析根系相关微生物群落的组成与多样性，对香蕉健康至关重要。尽管真菌同样可影响土传病害，但当前有益微生物群落的研究多聚焦于细菌类群。本研究针对真菌内部转录间隔区（internal transcribed spacer, ITS）开展高通量测序，系统解析了与香蕉枯萎病（Fusarium wilt, FW）相关的土壤真菌群落差异。相较于同一农田中的非根际土壤，健康植株与TR4侵染植株的根际真菌群落结构存在显著差异。侵染植株的根际土壤真菌群落丰富度与多样性均高于健康植株，其中镰刀菌属（Fusarium）的相对丰度高达14%，差异显著。健康植株根际土壤中，青霉菌属（Penicillium spp.）的相对丰度可达7%，且其丰度与土壤镁离子含量呈显著正相关。本研究详细描述了马来西亚地区健康与TR4侵染的香蕉根际土壤真菌群落结构，并筛选出可能与香蕉枯萎病发生、抑病相关的候选生物标记类群。本研究结果还丰富了全球范围内与受TR4侵染的无症状及显症香蕉植株相关的真菌群落数据库。