Variation of Rhizosphere Soil Microbial Flora in Healthy and Black Shank-Susceptible Tobacco Fields at Different Growth Stages

ZHANG Xiaoyu; DUAN Hongqun; LU Aqian; LI Hongli; WANG Yan

doi:10.15933/j.cnki.1004-3268.2018.03.013

Abstract：In order to control the occurrence of tobacco black shank,the changes of rhizosphere soil microbial flora during the growth of tobacco in healthy fields and susceptible fields were studied. The changes of microbial quantity,community structure and its diversity in the rhizosphere soil of tobacco fields were analyzed by detection of the number of culturable microorganisms in the rhizosphere soil and sequencing of the macro genome. The results showed that the number of cultivable microbes in the rhizosphere soil increased first and then decreased,reaching the maximum in the vigorous growing stage. The number of culturable bacteria and actinomycetes in the rhizosphere soil of healthy tobacco fields was higher than that in susceptible tobacco fields,while the number of fungi in susceptible tobacco fields was significantly higher than that in healthy tobacco fields in the mature period. The results of soil macro genome sequencing showed that the microbial diversity gradually decreased during the growth of tobacco, the diversity of soil bacteria in healthy tobacco fields was higher than that in susceptible tobacco fields, and the microbial community structure of rhizosphere soil was significantly different in healthy tobacco fields and susceptible tobacco fields in the mature period.The proportion of pathogen in the rhizosphere soil of susceptible tobacco fields increased rapidly with the growth of tobacco plant,reaching 60.43% in the mature period,with the incidence rate of 60%,while the proportion of soil pathogen in healthy tobacco fields was only 0.32%,with the incidence rate of 0.4%.It can be seen that the change of soil microbial community structure,the decrease of diversity and the increase of pathogen are the main causes of tobacco black shank.