Effects of Streptomyces lydicus M01 on growth, bacterial wilt incidence, and rhizosphere bacterial community composition of tomatoes

Abstract:

[Background] Streptomyces lydicus can efficiently promote the growth of many crops and inhibit many pathogenic fungi. However, there are few studies on the biocontrol effects of S. lydicus on bacterial wilt disease. [Objective] To explore whether S. lydicus M01 can promote tomato growth and inhibit tomato bacterial wilt disease and whether the effect of S. lydicus M01 on tomato growth is achieved by affecting the bacterial community structure in the rhizosphere.[Methods] The effects of S. lydicus M01 on plant growth, bacterial wilt incidence, and rhizosphere bacterial community composition of tomatoes were explored by the greenhouse pot experiments and high-throughput amplicon sequencing. [Results] Compared with the control, S. lydicus M01 increased fresh weight, dry weight, plant height, chlorophyll concentrations measured using soil and plant analyzer develotrnent methods, root vigor, and P content of tomato plants by 22.7%, 12.5%, 16.0%, 28.1%, 18.4%, and 17.9%, respectively. S. lydicus M01 significantly increased plant height, SPAD value, and P content of tomato plants (P<0.05). S. lydicus M01 delayed the onset time of bacterial wilt and decreased bacterial wilt incidence by 41.8% at 9 weeks after pathogen inoculation. Additionally, S. lydicus M01 had no significant effects on rhizosphere bacterial community composition (P=0.4 for microbiome composition at the phylum level and P=0.4 for microbiome composition at the genus level). [Conclusion] S. lydicus M01 can promote plant growth of tomatoes and suppress bacterial wilt of tomatoes, and these effects are not achieved by regulating rhizosphere bacterial community composition.

Key words:Streptomyces lydicus;tomatoes;bacterial wilt;rhizosphere bacterial community composition