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针对宁夏中部干旱带压砂西瓜田长期连作种植所产生的土壤退化、土壤养分含量降低、土壤真菌性病害增加、西瓜减产、品质下降等问题,从患病的西瓜植株上分离出致病菌-尖孢镰刀菌西瓜专化型(Fusarium oxysporum f.sp.niveum),从宁夏环香山地区压砂瓜集中连片种植区采集健康土壤中分离筛选对西瓜枯萎病致病菌有抑菌效果的拮抗菌株,并对拮抗菌株的防病效果以及分类鉴定进行了研究。通过采用平板稀释法筛选出对目标靶具有拮抗作用的拮抗细菌。通过初筛选取8株对目标靶具有拮抗作用的细菌进一步进行复筛试验。经过数据分析,G-1的抑菌率最大,且与其他处理间存在显著性差异,筛选出对目标靶拮抗最强的拮抗菌为G-1。根据形态学观察、细菌生理生化鉴定和16 S r DNA序列的同源性分析,确定拮抗菌株G-1为萎缩芽孢杆菌(Bacillus atrophaeus)。
In order to solve the problems of soil degradation, soil nutrient content, soil fungal disease increase, decrease of watermelon yield and quality in long-term consecutive cropping of watermelon in central arid zone of Ningxia, Fusarium oxysporum f.sp.niveum was isolated and screened from healthy soil collected from the contiguous planting area in Xiangxiang melon, Ningxia. The results showed that the Fusarium oxysporum f.sp.niveum had antibacterial activity against Fusarium oxysporum f.sp.niveum Strain, and antagonistic strains of the disease prevention and classification were identified. Antagonistic bacteria that antagonize the target of interest are screened by using a plate dilution method. Through screening, 8 strains of bacteria with antagonistic effect on the target were selected for further screening test. After data analysis, the antibacterial rate of G-1 was the largest, and there was a significant difference with other treatments. The antagonistic bacteria with the strongest antagonism to the target was screened as G-1. The antagonistic strain G-1 was identified as Bacillus atrophaeus according to morphological observation, bacterial physiological and biochemical identification and homology analysis of 16 S r DNA sequence.