低温茬口空闲期土壤强还原消毒对西瓜枯萎病的影响

为探明低温茬口空闲期土壤强还原消毒(RSD)对西瓜枯萎病的防控效果,设置对照(CK)、淹水对照(FCK)、淹水添加2%(w/w)苜蓿粉(AL)、0.25%(w/w)乙酸(AC)以及AL+AC的RSD处理进行西瓜盆栽试验,采用定量PCR和Illumina Miseq等测定真菌、尖孢镰刀菌数量及真菌群落组成,并统计发病率和产量。结果表明: 与CK相比,FCK和各RSD处理均能显著降低尖孢镰刀菌数量及其在真菌中的比例,杀菌效果达86.1%～94.6%;AL、AC以及AL+AC处理显著增加了西瓜产量,降低了枯萎病发病率,且枯萎病防控效果分别为63.2%、73.7%和94.7%,而FCK与CK无显著差异。与CK相比,AL和AC处理显著改变了土壤真菌群落组成,FCK处理对真菌群落无显著影响;RSD处理均显著增加了柄孢壳属、假散囊菌、地丝菌、粪盘菌、韦斯特壳属以及久浩酵母菌等优势属的相对丰度,且其中大部分与尖孢镰刀菌数量及其在真菌中的比例以及发病率呈显著负相关关系。综上,低温茬口空闲期的RSD处理可以通过重塑真菌群落组成有效防控西瓜枯萎病的发生。

Effects of reductive soil disinfestation during low-temperature stubble free period on the control of watermelon Fusarium wilt

In order to clarify the controlling effect of reductive soil disinfestation (RSD) during low-temperature stubble idle period on watermelon Fusarium wilt, we conducted a pot experiment, containing control (CK), flooded control (FCK), and RSD treatments incorporated with 2% (w/w) alfalfa meal (AL), 0.25% acetic acid (AC), and AL+AC. Real time PCR and Illumian Miseq sequencing were used to determine the abundances of fungi and Fusarium oxysporum as well as fungal community composition. The disease incidence and yield of watermelon were measured. Results showed that the abundance of Fusarium oxysporum and the ratio of Fusarium oxysporum to fungi significantly decreased in the FCK and three RSD treatments, and the disinfestation effects of these treatments ranged from 86.1% to 94.6%. The yield and disease incidence of watermelon significantly increased and decreased in all of the RSD treatments, respectively. There was no significant diffe-rence between FCK and CK treatments. The control efficiencies of Fusarium wilt in AL, AC, and AL+AC were 63.2%, 73.7%, and 94.7%, respectively. The compositions of fungal community in the AL and AC treatments were significantly changed, whereas FCK did not affect fungal community. The relative abundances of dominant fungal genera, such as Zopfiella, Pseudeurotium, Geotrichum, Ascobolus, Westerdykella, and Guehomyces, increased in the RSD treatments. Most of those genera were significantly and negatively correlated with the abundance of Fusarium oxysporum, the ratio of Fusarium oxysporum to fungi, and the disease incidence. In conclusion, RSD treated in the low-temperature stubble free period could effectively control watermelon Fusarium wilt by reshaping fungal community composition.