Abstract:

Chrysanthemum wilt (Fusarium oxysporum f. sp. chrysanthemi) is a root-invading disease that affects the development of chrysanthemum industry. In this study, Illumina MiSeq high-throughput sequencing was used to analyze the differences in rhizosphere soil microbial community structure between wilt-affected plants and healthy plants of chrysanthemum. The results showed that the incidence of chrysanthemum wilt had a significant impact on the abundance of the bacterial community in rhizosphere soil. The number of bacterial OTUs in the rhizosphere of healthy chrysanthemum plants and diseased chrysanthemum plants were 1831 and 1723, respectively, with a share of 1661. The total number of bacterial OTUs in the rhizosphere soil of healthy chrysanthemum plants was 6.23% higher than that of diseased plants, and the number of unique OTUs was 2.74 times that of diseased plants. From the diversity level of soil rhizosphere bacterial community structure, chrysanthemum wilt plants were lower than chrysanthemum healthy plants. Alpha diversity index showed that Shannon, Ace and Chao1 indexes of rhizosphere soil of chrysanthemum wilt plants were 1.60%, 5.71% and 6.62% lower than those of healthy plants, respectively. In addition, chrysanthemum wilt plants and chrysanthemum healthy plants also had significant differences in the structure of soil bacterial community diversity. In the rhizosphere soil of chrysanthemum healthy plants, the relative abundance of main α-proteobacteria, Bacilli, Chloroflexia were 10.27%, 1.50% and 9.54% higher than those of diseased plants, respectively. At the genus level, the relative abundance of genus Bacillus, Sphingomonas and Arthrobacter in the rhizosphere soil of diseased plants were 4.14%, 0.45% and 39.24% lower than those of healthy plants, respectively. The above results indicate that in the rhizosphere soil of chrysanthemum, the change of bacterial community structure and the reduction of species diversity are the key factors for the incidence of chrysanthemum wilt. This study will provide a theoretical basis for the control of chrysanthemum wilt.

Key words: chrysanthemum, rhizosphere soil, high-throughput sequencing, microorganism, bacterial community