生物有机肥育苗防控烟草青枯病

Nursery application of a novel bioorganic fertilizer on controlling tobacco bacterial wilt

【目的】烟草青枯病是影响贵州烟叶生产的主要土传病害之一。生物防控方法作为防控烟草青枯病体系的有效措施之一,寻求经济可行的途径势在必行。【方法】利用实验室自主筛选到的烟草青枯菌拮抗菌NJL-14,通过二次固体发酵研制成烟草专用拮抗青枯病型生物有机肥(BIO),选取K326和红花大金元两个烟草品种分别进行育苗和盆栽试验。育苗床基质分别添加BIO 1%、2%、3%、4%和5%,以确定适宜的BIO育苗添加量。盆栽试验两个品种分别设定五个处理:常规基质育苗+植烟健康土壤(CKn+CKp)、常规基质育苗+青枯病病土(CKn+Rs)、常规基质育苗+青枯病病土+有机肥(CKn+OFp)、常规基质育苗+青枯病病土+BIO(CKn+BIOp)、育苗和盆栽病土中都施入BIO(BIOn+BIOp)。分别采用荧光定量PCR和Biolog-ECO研究育苗基质和盆栽土壤中细菌和真菌数量变化,以及微生物功能多样性,特别是烟草青枯菌及其拮抗菌的消长关系。【结果】当BIO浓度在2%以内时,烟草的发芽率与对照无显著差异;与普通漂浮育苗相比,托盘育苗不但能稳定和延长拮抗菌NJL-14在根际的定殖,而且显著提高烟苗生物量,K326经BIO育苗处理的烟苗地上部和地下部的干重分别比常规基质育苗的处理高17.2%和30.8%,而红花大金元分别高14.9%和20.0%;采用育苗与移栽土壤双重使用BIO模式对烟草青枯病的防控效果明显,防控效果可以达到100%,明显优于只在盆栽中使用BIO模式,并且能够显著抑制土壤中病原菌数量在107 cfu/g土以下,同时有效提高土壤微生物生态多样性。【结论】采用育苗与移栽土壤双重使用烟草专用拮抗青枯病型生物有机肥模式可有效防控烟草青枯病,控制土壤中病原菌数量,改善土壤微生物功能多样性,为有效地生物防控烟草青枯病奠定基础。

[ Objectives ] Tobacco bacterial wilt is one of the most serious soil-borne diseases in tobacco growing area of Guizhou Province, China. Since bio-controlling tobacco bacterial wilt becomes more and more popular, it is of great importance to develop a high-efficient and economic way to bio-control this disease. [ Methods ] In this study, the antagonistic strain NJL-14 was isolated in our own lab, and a novel bioorganic fertilizer （BIO） was developed using the secondary solid-fermented approach. Nursery and pot experiments were conducted to evaluate efficiency of the BIO application on controlling tobacco bacterial wilt. In nursury substitute, 1%, 2%, 3%, 4% and 5% of BIO were added to test the suitable addition levles of BIO. In the follwing pot e^periement, the addition level was used in the soil basal treatment. Using the seedlings from the nursury without treated with BIO, four treatments were set up as ： healthy soil （un-infected with bacterial wilt）, sick soil （infected with wilt）, sick soil added with normal organic fertilizer, sick soil with BIO; and a treatment of using seedlings from BIO treated nursury and sick soil added with BIO. Real-time PCR and biology-ECO technology were employed to study population of bacteria and fungi in nursery substrate and soil, the soil microbial functional diversity, especially the effect on the reproduction ofRalstonia solanacearum and its antagonist. [ Results ] When the concentration of BIO was within 2%, there were no significant differences in the germination percentage between the control and the treatments. Compared with normal float seedlings, seedlings in tray stabilized the colonization of antagonistic strain NJL-14 in rhizosphere, and significantly increased tobacco seedling biomass. As for tobacco variety, K326, the dry weights of leaves and roots treated by BIO were increased by17.2% and 30.8% compared to the control. As for tobacco variety, Honghuadajinyuan, the dry weights of leaves and roots treated by BIO were 14.9% and 20.0% higher than that of the control. The best bio-control efficiency （100%） could be achieved by applying BIO at the nursery stage plus application in the transplanted soil, which was obviously better than the mode of only applying BIO in the pot experiment. Under the double-application mode, soil pathogen population was significantly depressed to less than 107 cfu/g soil. Meanwhile, the soil microbial functional diversity was improved a lot. [ Conclusions ] The mode of applying BIO at the nursery stage plus application in the transplanted soil could efficiently bio-control tobacco bacterial wilt, control soil pathogen concentration and improve soil microbial functional diversity. This work built a foundation for effectively bio-controtling tobacco bacterial wilt.