Dimethylhexadecylamine, a bacterial volatile compound, regulates achene germination, in vitro growth, and defense priming in Fragaria × ananassa

Abstract

Dimethylhexadecylamine, a bacterial compound, promoted strawberry achene germination and a long-lasting effect on plant growth; furthermore, it induced necrotrophic pathogen resistance possibly through crosstalk with the jasmonic acid pathway. Dimethylhexadecylamine (DMHDA) is a volatile compound produced by different beneficial plant bacteria. DMHDA induces growth and activates the jasmonic acid (JA) signaling pathway in plants. In this study, we analyzed the effects of synthetic DMHDA on achene germination, as well as the long-term effect on plant growth and plant pathogen resistance in vitro in strawberry plants. Strawberry achenes treated with 32 µM DMHDA showed a three-fold increase in germination rates compared with untreated achenes, and plants from achenes germinated with 64 µM DMHDA grew four times larger than plants from untreated achenes. When plants were cultured in vitro with DMHDA as a continuous stimulus, they produced 40% less shoot growth but showed an up to four-fold increase in crown weight compared with control plants. DHMDA also induced resistance significantly against the necrotrophic pathogenic fungus Botrytis cinerea in strawberry. Our data showed that the bacterial volatile compound DMHDA regulated achene germination and produced a long-lasting effect on plant growth; furthermore, it induced a defense priming response against a necrotrophic pathogen. Crosstalk between DMHDA and the JA and salicylic acid pathways, as a potential mechanisms of action underlying these effects, is also discussed.