|KIM, DA-RAN - Gyeongsang National University|
|JEON, CHANG-WOOK - Gyeongsang National University|
|SHIN, JAE-HO - Kyungpook National University|
|KWAK, YOUN-SIG - Gyeongsang National University|
Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2018
Publication Date: 1/16/2019
Citation: Kim, D., Jeon, C., Shin, J., Weller, D.M., Thomashow, L.S., Kwak, Y. 2019. Function and distribution of a lantipeptide in strawberry Fusarium wilt disease suppressive soils. Molecular Plant-Microbe Interactions. 32(3):306-312. https://doi.org/10.1094/MPMI-05-18-0129-R.
Interpretive Summary: The beneficial bacterium Streptomyces griseus strain S4-7 was isolated from the roots of healthy strawberry plants growing in soil in which the fungal pathogen Fusarium oxysporum, which causes a wilt disease of strawberry, also was present. Previous work has shown that these bacteria protect strawberry against the wilt pathogen. Streptomyces strains secrete many antibiotics, and we show here that strain S4-7 produces a new antibiotic named grisin that inhibits the wilt pathogen. The number of grisin-producing Streptomyces bacterial isolates increased with increasing numbers of years of strawberry cultivation in a field, and at least seven years was required for the bacterial population to reach a level high enough to control wilt disease. We suggest that the grisin biosynthesis gene can be used as a diagnostic marker to determine whether the population of grisin-producing bacteria in a strawberry monoculture field has reached a level high enough to control the wilt disease pathogen.
Technical Abstract: Streptomyces griseus S4-7 is representative of strains responsible for the specific soil suppressiveness of Fusarium wilt of strawberry caused by Fusarium oxysporum f. sp. fragariae. Members of the genus Streptomyces secrete diverse secondary metabolites including lantipeptides, heat-stable lanthionine-containing compounds that can exhibit antibiotic activity. In this study a class II lanthipeptide provisionally named grisin, of previously unknown biological function, was shown to inhibit F. oxysporum. The inhibitory activity of grisin distinguishes it from other class II lantipeptides from Streptomyces spp. Results of qRT-PCR with lanM-specific primers showed that the density of grisin-producing Streptomyces in the rhizosphere of strawberry was positively correlated with the number of years of monoculture, and a minimum of seven years was required for development of specific soil suppressiveness to Fusarium wilt disease. We suggest that lanM can be used as a diagnostic marker of whether a soil is conducive or suppressive to the disease.