拮抗菌强化的生物有机肥对西瓜枯萎病的防治作用

由西瓜专化型尖孢镰刀菌(Fusarium oxysporum f.sp.niveum)引起的西瓜枯萎病是导致西瓜生产毁灭性损失的土传病害,当前对该病尚无有效的防治措施.为了探索该病的生物防治效果,本研究从土壤中分离筛选西瓜枯萎病的拮抗菌,制成生物有机肥,通过温室盆栽试验检验防病效果,并对与拮抗相关的拮抗菌葡聚糖酶进行分子生物学检测.从不同土壤中分离纯化到对西瓜枯萎病菌有潜在拮抗作用的细菌172株,通过平板对峙法筛选出抑菌率在60％以上的拮抗细菌13株,从中挑选出2株抑菌率最高的菌株Cy5和CR38,分别用其与已腐熟的有机肥制成生物有机肥BIO5和BIO38.盆栽试验结果表明,BIO5在防病和促进西瓜生长方面表现优于BIO38.与对照相比,BIO5和BIO38对西瓜枯萎病的相对防治率分别为75％和25％.BIO5处理植株的株高、地上部鲜重、地上部干重分别比对照增加64.8％、63.0％和50％.施用生物有机肥还能显著改变根际土壤的微生物组成.BIO5处理根际土壤的细菌和枯草芽孢杆菌数量分别比对照增加48.5％和61.1％,真菌和尖孢镰刀菌的数量比对照分别下降52.1％和70.2％.分子生物学分析表明,菌株Cy5属于Paenibacillus jamilae菌株,并含有类似于P.polymyxa的β-1,3-1,4-葡聚糖酶.本研究结果说明,拮抗菌强化的生物有机肥对西瓜枯萎病有防治潜力.

Control of watermelon fusarium wilt by using antagonist-enhanced biological organic fertilizers

Fusarium wilt of watermelon caused by Fusarium oxysporum f. sp. niveum is a destructive soil borne disease in watermelon production. However, no effective method has been developed to control the disease. For exploration of a biological control method against the wilt, antagonistic bacteria were isolated, screened and used to make biological organic fertilizers, which were further tested for their disease control effectiveness by a greenhouse pot experiment. The antagonism related β-1,3-1,4-glucanase was also detected by a molecular biological procedure. A total of 172 strains were isolated from rhizosphere soils of different fields. Among the strains, 13 strains had the inhibition rates more than 60% in antagonistic plates and two strains Cy5 and CR38 with the highest inhibition rates were used to make biological organic fertilizers, i.e. BIO5 and BIO38, respectively, for greenhouse pot experiments. The results showed that BIO5 microbial composition in performed better than BIO38 in control of the disease and promotion of the growth of watermelon. The relative control rates of BIO5 and BIO38 were 75% and 25%, respectively, as compared with the control. The averages of height, fresh weight and dry weight of the plants in the treatment of BIO5 were increased by 64.8%, 63.0% and 50%, respectively, in comparison with the control. BIO5 also significantly improved rhizosphere soil of watermelon. BIO5 increased the numbers of bacteria and bacillus subtilis in rhizosphere soil of watermelon by 48.5% and 61.1%, respectively, and decreased the numbers of fungi and F. oxysporum by 52.1% and 70.2% respectively, as compared with the control. Molecular analysis showed that strain Cy5 belonged to Paenibacillus jamilae and contained β-1,3-1,4-glucanase similar to that of P. polymyxa. We concluded that the antagonist enhanced biological organic fertilizer had control potential against Fusarium wilt of watermelon.