Changes in the Molecular Function Pathways of Ulva rigida throughout the Blooming Season

The macroalgal genus Ulva, commonly known as “sea lettuce”, develops into harmful macroalgal blooms (dense, floating aggregations) in shallow coastal systems worldwide, including Narragansett Bay, RI. These blooms have significant negative ecological and economic impacts on coastal communities. However, little data exist on the genetic makeup and underling functional genetics that link bloom dynamics to environmental changes, especially with respect to climate change.  To this end, we embarked on a one-year metagenomics study to begin to understand the link between pathway expression changes, bloom dynamics and the environment.  This was completed by sampling two abundant bloom-forming Ulva populations at three sites around the Narragansett Bay, RI at relevant stages of the bloom cycle.  After collection, samples were identified and RNA was extracted and sequenced using HiSeq 2000 NGS technology.  The resulting sequence was assembled using the Geneious software, and was annotated using Blast2Go.  This combined data indicated large gene expression changes throughout the year that could be indicative of bloom formation providing one of the first insights to the genomics of this behavior. In particular, protein-binding transcription factor activity, receptor activity and electron carrier activity have shown to have a greater change in gene expression in the functional pathways across the months of May, July and September. Moreover, some individual gene expression profiles can be leveraged to act as markers to predict macroalgal blooms.