[Effect of different treatment on endophytic bacterial communities in continuous cropping of Chrysanthemum morifoliu]

To reveal the effect of rotation cropping and bacterial manure on the growth of Chrysanthemum morifolium and screen the beneficial endophytic, the diversity of endophytic and dominant genera of different treatment groups were analyzed. Four different treatments were continuous cropping, rotation, self-made organic fertilizer and commercially available fertilizer, respectively. Endophytic bacterial diversity and dominant genera in different organs were examined using Terminal Restriction Fragment Length Polymorphism (T-RFLP). The results showed that enzyme Hae III was more appropriate than enzyme Hinfl because the number of TRFs digested by enzyme Hae III was more than that of enzyme Hinfl. In comparison of diversity, the endophytic bacterial communities' diversity index in group of cropping rotation and fertilizer was higher than that of continuous cropping which indicated that the addition of exogenous microorganism in soil could increase the diversity of plant endophyte. 18 dominant species were selected, including 3 kinds of Firmicutes, 4 kinds of Actinomycetes and 11 kinds of Proteobacteria. The results of dominant species comparison showed that the number of dominant species in continuous cropping of Ch. morifolium was significantly less than that of the rotation group. Some dominant bacteria in rotation group and fertilizer group such as Arthrobacter, Streptomyces, Streptomyces, Flavobacterium and Mycobacterium were not found in the continuous cropping of Ch. mortfolium group. Dominant species of fertilizer treatment group was similar with the rotation group, and the continuous cropping group's dominant species was more abundant. It indicates that these bacteria may be able to mitigate hindrance in continuous cropping, especially the Flavobacterium which can decompose the pathogenic fungi is worthy of further attention. Compared with leaves, there are more dominant species in roots and stems. The diversity of edophytic bacterial communities in continuous cropping of Ch. morifolium stays below than that in the rotation of Ch. morifolium, and fertilizer treatment can increase the diversity of continuous cropping so that it could mitigate hindrance in continuous cropping.