Sudden marsh diebacks, or brown marsh, occur throughout the range of Spartina alterniflora, threatening the health and ecosystem services of salt marshes. The causes of sudden marsh dieback are controversial, and despite widespread interest, little progress has been made in identifying them. The researchers propose a generalized mechanism of increasing stress susceptibility with stand age. They will conduct experimental and observational studies to test if sudden marsh dieback is impacted by epigenetic changes that accumulate with stand age. This work focuses on testing assumptions and developing methods necessary to investigate the role of genetic determinants in marsh dieback and to assess how they influence the susceptibility of marsh environmental stress. Namely, the research team will quantify epigenetic modifications in plants using the level of DNA methylation in plant tissues.
The researchers plan to (1) assess the variation in genome-wide DNA methylation among different tissue types in Spartina ramets, (2) measure the spatial variation in genome-wide DNA methylation across a marsh landscape, (3) measure the genome-wide DNA methylation across asexual generations (different ages) of Spartina alterniflora, (4) test for an association between methylation and salinity tolerance, predicting that higher methylation leads to a smaller range of salinity tolerance, and (5) develop a diagnostic technology which can report on the status of the epigenetic aging process in salt marsh stands.
Research Results
Agrelius, Trenton, Jeffry L. Dudycha, and James T. Morris. “Global DNA cytosine methylation variation in Spartina alterniflora at North Inlet, SC,” PLOS One, September 10, 2018.
Agrelius, Trenton. Master’s thesis, “Global Methylation of DNA among Spartina alterniflora Clones Differing in Age at North Inlet, SC,” December 2015, University of South Carolina.