Objective The aim of this study was to elucidate the effect of associated chives on bacterial wilt and microecological characteristics of tomato rhizosphere, and to reveal the mechanism of reducing incidence of tomato bacterial wilt.

Method Two treatments of tomato monoculture and tomatoes with chives were set for field experiments, and rhizosphere soils of diseased tomatoes in tomato monoculture treatment (QK), healthy tomatoes in tomato monoculture treatment (NBS) and tomatoes with chives treatment (BS) were collected. And the effects of companion chives on the micro-ecological characteristics of tomato rhizosphere were investigated by using 16S rDNA high-throughput sequencing and liquid chromatography-mass spectrometry.

Result The results of field experiments showed that the average disease incidence of tomato bacterial wilt were 50.48% in tomato monoculture treatment and 31.43% in companion chives treatment. The control effect of companion chives on tomato bacterial wilt was 37.74%. According to the resulyts of 16S rDNA high-throughput sequencing, the relative abundance and diversity of bacterial communities in the rhizosphere soils of BS and NBS were significantly higher than those of QK. Compared with QK, the relative abundance of Ralstonia in the rhizosphere soils of BS and NBS was significantly lower than that of QK, and the relative abundance of Bacillus was higher than that of QK. Moreover, compared with NBS, the relative abundance of Ralstonia in the rhizosphere soil of BS was reduced, and the relative abundance of Bacillus was significantly enhanced. A total of 586 metabolites in tomato rhizosphere soil were identified by using LC-MS, including 320 positive ion mode metabolites and 266 negative ion mode metabolites. The functions of metabolites were annotated to metabolic pathways such as metabolism, genetic information processing and environmental information processing. Compared with NBS, the contents of valine, L-asparagine and citric acid in BS rhizosphere soil were significantly lower than those in NBS, and the contents of L-lysine, glutamic acid, D-glutamine and isoleucine in rhizosphere soil of BS were also lower than those of NBS, though, the difference was not significant.

Conclusion The companion chives significantly reduced the disease incidence of tomato bacterial wilt in the field, and changed the bacterial community structure and metabolite contents in tomato rhizosphere soil.