Priming of Marine Macrophytes for Enhanced Restoration Success and Food Security in Future Oceans

Alexander Jueterbock,Melinda A. Coleman,Zi-Min Hu,Ralf Rautenberger,Jie Zhang,Lydia Scheschonk,Antoine J. P. Minne,Thomas Wernberg,J. Mark Cock

doi:10.3389/fmars.2021.658485

Abstract

Marine macrophytes, including seagrasses and macroalgae, form the basis of diverse and productive coastal ecosystems that deliver important ecosystem services. Moreover, western countries increasingly recognize macroalgae, traditionally cultivated in Asia, as targets for a new bio-economy that can be both economically profitable and environmentally sustainable. However, seagrass meadows and macroalgal forests are threatened by a variety of anthropogenic stressors. Most notably, rising temperatures and marine heatwaves are already devastating these ecosystems around the globe, and are likely to compromise profitability and production security of macroalgal farming in the near future. Recent studies show that seagrass and macroalgae can become less susceptible to heat events once they have been primed with heat stress. Priming is a common technique in crop agriculture in which plants acquire a stress memory that enhances performance under a second stress exposure. Molecular mechanisms underlying thermal priming are likely to include epigenetic mechanisms that switch state and permanently trigger stress-preventive genes after the first stress exposure. Priming may have considerable potential for both ecosystem restoration and macroalgae farming to immediately improve performance and stress resistance and, thus, to enhance restoration success and production security under environmental challenges. However, priming methodology cannot be simply transferred from terrestrial crops to marine macrophytes. We present first insights into the formation of stress memories in both seagrasses and macroalgae, and research gaps that need to be filled before priming can be established as new bio-engineering technique in these ecologically and economically important marine primary producers.

Highlights

Marine macrophytes, including seagrasses and macroalgae, form the foundational basis of some of the most productive and diverse coastal marine ecosystems on the planet (Larkum et al, 2006; Costanza et al, 2014; Klinger, 2015; Teagle et al, 2017) that provide ecosystem services worth US$ 28.9 ha−1 year−1 (Costanza et al, 2014)
Marine macrophytes are increasingly threatened by a variety of anthropogenic stressors, including coastal development, invasive species, agricultural run-offs, dredging, aquaculture, and rising sea levels (Orth et al, 2006; Krumhansl et al, 2016; Chefaoui et al, 2018; Filbee-Dexter and Wernberg, 2018)
One-third of global seagrass areas have disappeared over the last 100 years (Waycott et al, 2009) and 60% of macroalgal forests have been in decline over the past 2–5 decades (Wernberg et al, 2019)

Summary

Introduction

Marine macrophytes, including seagrasses and macroalgae, form the foundational basis of some of the most productive and diverse coastal marine ecosystems on the planet (Larkum et al, 2006; Costanza et al, 2014; Klinger, 2015; Teagle et al, 2017) that provide ecosystem services worth US$ 28.9 ha−1 year−1 (Costanza et al, 2014). Priming relies on the formation of a molecular stress memory (Box 1), a process that can include epigenetic mechanisms such as microRNAs (miRNAs), histone modifications, and DNA methylation (Iwasaki and Paszkowski, 2014; Balmer et al, 2015; Crisp et al, 2016; Hilker et al, 2016; Wojtyla et al, 2016; Gallusci et al, 2017; Lämke and Bäurle, 2017; Bäurle, 2018; Figure 2).

Results

Conclusion