| In order to better exertion of microbial resources′ role to maintain the brand of produce with geographical indications, high-throughput sequencing technology was employed to evaluate the structure and composition of the rhizosphere bacterial community of Shawo radish in Xiqing District, Tianjin city. The relationship between rhizosphere microorganisms and the quality of Shawo radish was evaluated by the effect of pure culture of rhizosphere soil bacteria on the quality of cherry radish fruit and the content of flavonoids, polyphenols, vitamin C, soluble sugar. The results showed that Shawo radish possesses rhizosphere bacteria from 5 phyla and 9 genera, of which Pseudomonas, Bacillus and Saccharimonspora were the core bacterial communities. A total of 39 culturable bacterial strains were obtained through pure culture. Seven strains with high nitrogen fixation ability, phosphorus degradation capacity or secretion of auxin and growth-promoting capacity were screened and obtained from the 39 strains, namely strains J3, J5, H11, X3, X6, X10 and X13. Based on 16S rRNA gene sequence, these strains were identified as Proteus mirabilis, Pseudomonas entomophila, Bacillus megaterium, B. cereus, B. huizhouensis, P. terrae, and Serratia marcescens. The results of the pot experiment showed that the application of seven strains could significantly promote the growth of cherry radish plants or improve their quality. Strains H11, J5 and X13 increased the weight of cherry radish fruit by 47%, 45% and 42%. Strains H11 and J5 increased fruit flavonoids by 47% and 40%, while strains J5 and X6 increased polyphenols by 70% and 67%. Strain X6 had advantages in improving vitamin C content (24.60±5.07) mg/100 g in the fruit, and was 3 times higher than control groups. In addition, soluble sugar content in fruit treated with strain H11 was 2.7 times higher than in the control group. The above results indicated that excavating rhizosphere microbial resources around Shawo radish conducive to the utilization of bacterial community to enact effective and sustainable strategies for crop field management. |
