Variability in dimethylsulfoniopropionate (DMSP) concentrations in Spartina alterniflora and the effect on Littoraria irrorata

Abstract

We measured concentrations of dimethylsulfoniopropionate (DMSP) in Spartina alterniflora (Loisel.) in response to the plant hormones abscisic acid (ABA), jasmonic acid (JA), and salicylic acid (SA) to determine whether DMSP concentration is linked to any of their signaling pathways. DMSP concentrations were also measured in plants at a salt marsh dieback site in Georgetown County, South Carolina (USA), to determine whether dieback conditions affect foliar DMSP concentrations. We found elevated levels of DMSP in plants receiving SA treatment compared to a control treatment, but we found no treatment effect for either of the other 2 hormone treatments. This suggests that DMSP production or transformation is linked to the SA signaling pathway. Diminished levels of DMSP were observed in plants nearest the dieback edge compared to those farthest from the dieback in an apparently healthy marsh, which suggests that DMSP concentration responds to environmental conditions connected with salt marsh dieback. Using a ring assay, we found that Littoraria irrorata snails, potential herbivores of S. alterniflora, were attracted to DMSP. However, we found no correlation between DMSP concentration and L. irrorata density at the acute dieback site. These results suggest that factors such as plant biomass may play a more important role than DMSP in determining L. irrorata distribution in dieback areas. KEY WORDS: Stress hormone · Attractant · Deterrent · Salt marsh dieback Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 406: [47][48][49][50][51][52][53][54][55] 2010 more frequently by rice rats Oryzomys palustris compared to plants in unfertilized plots. They observed that the rats had chewed through the sheath of the stem in order to reach the younger shoots inside. Upon further analysis, the investigators found that the inner tissue of the stems that the rice rats were probably trying to reach contained a much lower concentration of DMSP than the same tissue from the unfertilized plants ( Otte et al. 2004). These observations, along with others (Dacey & Wakeham 1986, Nakajima 1989, Wolfe & Steinke 1996, Wolfe et al. 1997, Van Alstyne & Houser 2003, suggest that DMSP may act as an herbivore deterrent. Attractant properties of DMSP have also been observed. Van Alstyne et al. (2001) demonstrated that DMSP can act as a feeding attractant for the purple sea urchin Strongylocentrotus purpuratus and the green sea urchin Strongylocentrotus droebachiensis. DMSP is also a foraging cue for certain species of planktivorous reef fishes (DeBose et al. 2008). DMSP released during algal grazing by zooplankton allows fishes to 'eavesdrop on trophic interactions' (DeBose et al. 2008) by recognizing that the presence of residual DMSP is an indication of prey presence. In a similar way, DMSP produced by S. alterniflora or ephiphytic algae growing on S. alterniflora and marsh substrate may act as a foraging or orientation cue for herbivores, enabling them to identify potential food or re...

Foliar DMSO:DMSP ratio and metal content as indicators of stress in Spartina alterniflora

“…Foliar DMSP was found at decreased concentrations nearest sudden dieback areas in South Carolina (Kiehn & Morris 2010) and in visibly stressed (yellowing) Spartina alterniflora in Alabama (Husband & Kiene 2007). We observed a similar pattern of DMSP concentrations at the Georgia dieback sites examined here: leaves and stems taken from healthy zones, located approximately 10 m from the dieback, had higher concentrations of DMSP than did those collected from the edge zones.…”

“…These DMSP concentrations were within the range that has been previously reported in healthy Spartina alterniflora (Otte & Morris 1994, Husband & Kiene 2007, Kiehn & Morris 2010. The DMSO concentrations observed here were as much as 2 to 3 times higher than the only other study in which they were measured (leaves: ~0.60 ± 0.20 µmol g −1 FW; stems: ~0.36 ± 0.15 µmol g −1 FW; Husband & Kiene 2007).…”

“…Studies in sudden dieback areas have reported 2 different types of physiological responses in Spartina alterniflora plants that may reflect general (oxidative) stress: lower concentrations of dimethylsulfoniopropionate (DMSP) and increased concentrations of metals (Fe, Al) were found in leaves of S. alterniflora collected near dieback areas as compared to healthy marsh areas in South Carolina and Louisiana, respectively (McKee et al 2004, Kiehn & Morris 2010. DMSP is a secondary metabolite synthesized by S. alterniflora from the amino acid methionine, and has been speculated to be an herbivore deterrent/attractant, a sulfur detoxifying agent, and an antioxidant (Kocsis et al 1998, Sunda et al 2002, Husband & Kiene 2007.…”

Evolution of DMSP (dimethylsulfoniopropionate) biosynthesis pathway: Origin and phylogenetic distribution in polyploid Spartina (Poaceae, Chloridoideae)

“…Hubb. (Larher et al, 1977), but later in Spartina alterniflora Loisel (Colmer et al, 1996;Dacey et al, 1987;Husband et al, 2012;Kiehn and Morris, 2010;McFarlin and Alber, 2013;Otte and Morris, 1994), Spartina foliosa Trin. (Otte and Morris, 1994) and Spartina maritima (Curtis) Fernald (Otte and Morris, 1994).…”

Chemical Speciation of Copper in a Salt Marsh Estuary and Bioavailability to Thaumarchaeota

“…As well as water column sources for ligands, likely sources of thiols are benthic microbes and sulfur-containing amino acids within the sediment (Kiene et al, 1990;Chapman et al, 2009), whilst the humics in this type of environment are likely products of relatively recent degradation of local plant matter (Averett et al, 1994) such as fungal breakdown of lignocellulose (Newell, 2001;Buchan et al, 2003). Spartina alterniflora and many of the higher plants in the marsh also release dimethylsulfoniopropionate (DMSP) (Bacic et al, 1998;Kiehn and Morris, 2010), which can add be an additional source of thiols.…”