Genetic diversity in smooth cordgrass from brown marsh areas of Louisiana

Document Type

Article

Publication Date

7-4-2008

Abstract

Smooth cordgrass (Spartina alterniflora Loisel.) is the single most important grass species in salt marshes along the Gulf of Mexico and the eastern United States coastline. In spring 2000, coastal Louisiana experienced rapid and large scale damage to its salt marshes due to a brown marsh event. We analyzed the genetic relationship among the S. alterniflora samples collected from the severely affected dead zones and lightly affected peripheral transition zones of brown marshes and compared it with those from healthy marsh areas. Forty S. alterniflora individuals collected from 18 brown marsh and 6 healthy non-brown marsh sites were fingerprinted using amplified fragment length polymorphism (AFLP) markers. Twelve EcoRI/MseI primer combinations produced 684 scoreable fragments, of which 59.9% were polymorphic. Each S. alterniflora individual was clearly distinguished by its unique AFLP fingerprint. Individuals from healthy marshes were clearly separated from individuals of brown marsh-affected areas in UPGMA cluster analysis. Individuals in closer proximity to each other tend to be more genetically related than those sampled in distantly located sites. Partitioning of the genetic variability by analysis of molecular variance (AMOVA) showed that the within-group variance component was high (91%) compared to the between-group component (9%). This preliminary study suggests that the surviving brown marsh individuals are genetically different from those of healthy marshes, and their survival could be due to favorable combination of genes responsible for tolerance to multiple abiotic stresses. However, further confirmation by DNA assay and field evaluation using large sample size is necessary to identify die-back tolerant genotypes for marsh restoration projects.

Publication Source (Journal or Book title)

Journal of Aquatic Plant Management

First Page

60

Last Page

67

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