Oxidation of dimethylsulfoniopropionate (DMSP) in response to oxidative stress in Spartina alterniflora and protection of a non-DMSP producing grass by exogenous DMSP + acrylate

We investigated the possible role of dimethylsulfoniopropionate (DMSP) as an antioxidant in Spartina alterniflora (Smooth cordgrass). Experimentally applied oxidative stress caused by application of the herbicides, 1,1′-dimethyl-4,4′-bipyridinediium dichloride (Paraquat), and 1,1-dimethyl-3-(3,4-dichlorophenyl)urea(DCMU)to the leaves of S. alterniflora resulted in increased oxidation of DMSP to dimethylsulfoxide (DMSO). We did not see an increase in DMSP synthesis and accumulation in response to herbicide induced oxidative stress. The role of DMSP in oxidative stress protection was further investigated via the exogenous application of Paraquat and DMSP + acrylate to leaf discs of the non-DMSP producing grass Panicum commutatum (Panic grass). Inclusion of DMSP + acrylate in the treatment medium resulted in significantly less tissue damage as indicated by decreased tissue necrosis, and chlorophyll bleaching.While the lack of enhanced synthesis of DMSP suggests that DMSP may not function solely as an antioxidant in S. alterniflora, ourresults show that the ability of S. alterniflora to synthesize DMSP may partially explain its ability to thrive in the stressful low marsh environment.

► Oxidative stress did not result in increased DMSP levels in S. alterniflora leaves.
► Oxidative stress increased oxidation of DMSP to DMSO in S. alterniflora leaves.
► Addition of DMSP to paraquat treatments resulted in less damage to treated tissue.