Constitutive expression of GmF6'H1 from soybean improves salt tolerance in transgenic Arabidopsis.

Coumarin plays a pivotal role in plant response to biotic stress, as well as in the mediation of nutrient acquisition. However, its functions in response to abiotic stresses are largely unknown. In this work, a homologous gene, GmF6'H1, of AtF6'H1, which encodes the enzyme catalyzing the final rate-limiting step in the biosynthesis pathway of coumarin, was isolated from soybean. GmF6'H1 protein shares very high amino acid identity with AtF6'H1, and expression of GmF6'H1 in atf6'h1 can successfully restore the decreased coumarin production in the T-DNA insertion mutant. Further study revealed that the expression of GmF6'H1 in soybean was remarkably induced by salt stress. Constitutive expression of GmF6'H1 in Arabidopsis, driven by 35S promoter, significantly enhanced the resistance to salt of transgenic Arabidopsis. All these results suggest that GmF6'H1 can be used as a potential candidate gene for the engineering of plants with improved resistance to both biotic and abiotic stresses.