综合生物防控烟草青枯病及其对土壤微生物群落结构的影响

利用生物有机肥结合相应的农艺措施进行生物防控是近年来的研究热点。分别采用常规施肥(T1)、常规施肥+生石灰(T2)、常规施肥+L-25生物有机肥(T3)、常规施肥+生石灰+L-25生物有机肥(T4)四个处理来探究生物防控烟草青枯病的效果。结果表明:2014年T4处理在烟草全生育期的防控效果显著高于T2和T3处理,在90d后防控效果分别是T2和T3的6.26倍和1.99倍。经过三年修复,青枯病综合防控效果高达61.3%。2013年和2014年T4处理产量显著高于其他各处理。2013年生物有机肥各处理的拮抗菌在70 d之前均显著高于各自对应的病原菌数量,2014年T4病原菌数量则始终处于106 cfu g-1数量级以下,其他处理在烟草移栽90 d后病原菌数量均增长至107 cfu g-1以上。T4处理的根际土壤微生物物种丰度水平、运算分类单位(OTU)、香农多样性指数(Shannonindex)均高于T1处理,主成分与聚类分析表明T3和T4处理的微生物区系结构相似,明显不同于T1处理。综合的生物防控措施可以有效防控重病区青枯病,对烤烟产量产值具有明显的提高作用,并能有效改良土壤微生物区系,具有良好的推广应用前景。

Integrated Bio-control of Tobacco Bacterial Wilt and Its Effect on Soil Microobial Community Structure

Objective]Tobacco bacterial wilt is one of the most serious soil-borne pests affecting tobacco production in Southwest China. Biocontrol of tobacco bacterial wilt has been a hot research topic in recent years. For control of the pest,a kind of biomanure prepared out of microbes antagonistic to the pest is used together with some proper agronomic measures,so as to achieve sustainable and healthy development of tobacco production.[Method]In this study,a three-year long field experiment was conducted in a severely wilt infected tobacco field in Guizhou Province to explore effects of the pest control measures. The experiment was designed to have four treatments or measures,that is,T1(Conventional fertilization), T2(Conventional fertilization + liming),T3(Conventional fertilization + L-25 Biomanure)and T4 (Conventional fertilization + liming + L-25 Biomanure). High-throughput sequencing was done of the microbial genome in the rhizosphere to explore effects of the integrated control measures on soil microflora.[Result]The experiment indicated thatin 2013 Treatment T4 was significantly(p<0.05)higher than Treatments T2 and T3 in controlling effect during the entire tobacco growing period,and in 2014,Treatment T4 was significantly higher than Treatments T2 and T3 in controlling effect,60 days after transplanting and 6.26 and 1.99 times as high as Treatments T2 and T3,respectively,90 days after transplanting. At the end of the experiment,the pest controlling effect reached up to 61.30%. In 2013,Treatment T4 was significantly higher than all the other treatments in tobacco yield or 3.71,1.61 and 1.13 times as high as Treatment T1,T2 and T3,respectively. In 2014,Treatment 4 was the highest in tobacco yield and output value and Treatment T3 was significantly higher than the other two,which were more or less the same. In 2013,although the pathogen in the treatments amended with biomanure slowly increased in population,the counts of antagonistic bacteria in the treatments were higher than those of pathogen during the initial 70 days after transplanting, while in 2014,the population of pathogen in Treatment T4 was always kept below the level of 106 cfu g-1 soil,but the counts of pathogen in all the other treatments grew beyond the level of 107 cfu g-1 soil,90 days after transplanting and on. Treatment T4 was higher than Treatment T1 in microbial species abundance, operational taxonomic unit(OTU)and Shannon index. Principal component and cluster analysis shows that Treatments T3 and T4 were quite similar,but significantly different from Treatment T1 in microfloral structure. [Conclusion]The integrated measure,(like Treatment T4)can effectively control tobacco bacterial wilt and significantly improve yield and output value of cured-tobacco,and soil microflora as well, which demonstrates that the measure has a promising application and extension prospect.