Abstract Detail

Plant Resilience to Climate Challenges

Waller, Jeffrey [1].

Oceanic resilience: Discovering how marine algae make an “all-in-one” molecule to combat stress.

Photosynthetic organisms in the ocean face a variety of stresses, both biotic and abiotic, that some marine algae combat with a single molecule. Dimethylsulfoniopropionate (DMSP) is an important algal metabolite enzymatically synthesized from methionine by a 4-step pathway. Certain marine macroalgae make DMSP in massive quantities and appear to use DMSP for osmoprotection, cryoprotection, herbivory deterrence, and scavenging reactive oxygen species to cope with these environmental stresses. After DMSP is inevitably released from the cell into the ocean, marine bacterial communities can take up and use DMSP as a carbon and fixed sulfur source, yielding dimethylsulfide (DMS) as a byproduct. After release to the environment, DMS in seawater then enters the biogeochemical sulfur cycle. Dissolved DMS will eventually be volatilized to the atmosphere where it constitutes ~50% of the global atmospheric sulfur budget and may play a role in global climate regulation where it acts as a climate-cooling agent. Since DMSP is the source of DMS, it is surprising that little about DMSP biosynthesis is known and not one biosynthetic enzyme has been identified. Given the importance of DMSP to algae, marine ecology, biogeochemistry, and the global climate, identifying DMSP metabolic enzymes and the genes encoding them should be a priority. In the late 1990s, a combination of isotope labelling and radiometric enzyme assays was used to elucidate the DMSP biosynthesis pathway in Ulva intestinalis. However, the discovery and characterization of the enzymes responsible for DMSP metabolism, and their underlying genes, has been effectively stalled since then due to a lack of practical analytical methods and an absence of comparative genomic resources. As a first step towards ultimately understanding how algae control DMSP metabolism, we have developed a variety of methods to aid in measuring DMSP enzymes so we can identify and characterize them. Progress in developing and exploiting tools to understand DMSP metabolism will be presented.

Related Links:
Waller lab website

1 - Mount Allison University, Chemistry and Biochemistry, 63C York Street, Room 119 Barclay Building, Sackville, NB, E4L1G8, Canada

Keywords:
macroalgae
Enzyme activity
metabolism
sulfur
osmoprotectant.

Presentation Type: Symposium Presentation
Session: SY18
Location: Hall A/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 2:45 PM
Number: SY18004
Abstract ID:820
Candidate for Awards:None