Dataset: Peroxide quantification in Thalassia testudinum tissue and response to pathogenic Labyrinthula in seagrass collected February 2024 in Tampa Bay, Florida

Background

Seagrasses represent a diverse and highly productive functional group of marine angiosperms that provide an array of vital ecosystem services to coastal communities, including sediment stabilization, carbon sequestration, improvement of water quality, mitigation of ocean acidification, and habitat provision for commercially and recreationally important species (Duarte et al., 2013; Fourqurean et al., 2012; Hendriks et al., 2014; Lefcheck et al., 2019; Heck et al., 2003). While abiotic stressors, in isolation or in combination, have been shown to cause a negative impact on seagrass beds, there continues to be much less data available on how biological factors, such as seagrass wasting disease (SWD), contribute to population declines (Sullivan et al., 2018). 

Heterotrophic protists of the genus Labyrinthula, family Labyrinthulaceae, play an etiological role in SWD, contributing strongly to epidemic events (Sullivan et al., 2013). Recent years have provided substantial insights into the seagrass-Labyrinthula pathosystem. However, T. testudinum has remained relatively understudied when compared to the information available on SWD interactions in other seagrass species (Eisenlord et al., 2024, Dawkins et al., 2018; Brakel et al., 2019; Graham et al., 2023; Groner et al., 2021; Duffin et al., 2021; Pagenkopp Lohan et al., 2024). Although such work has started to establish the foundational relationships between key abiotic factors and occurrences and severity of SWD, reports on the physiological and cellular mechanisms underpinning host immune responses in seagrasses are very limited in scope. 

Seagrasses convergently evolved from terrestrial angiosperms and underwent aquatic recolonization in their lineage over ~75 Ma. This process included a number of genomic changes to attain the structural and cellular adaptations required to live in a marine environment (Olsen et al., 2016). Despite these changes, it still seems highly plausible that select components of the seagrass immune system would remain analogous to their well-studied terrestrial counterparts (Janssen & Bremer, 2004; Lee et al., 2018; Castel et al., 2024).

While the hypersensitive cell death process is considered to be a major element of terrestrial plant disease resistance, its occurrence and associated characteristics have not been described in detail in any seagrass species, to our knowledge. Turtlegrass, T. testudinum, has been selected for investigation given its characteristics as a dominant, long-lived, tropical/subtropical seagrass that serves  as an important foundational species (van Tussenbroek, 2007). Taking into consideration the continued decline of seagrasses due to wasting disease, this work is both timely and critical in addressing the paucity of data surrounding innate immune responses in marine vascular plants, specifically T. testudinum.