Can targeted defense elicitation improve seaweed aquaculture?

Gaoge Wang,Xiaojiao Wei,Esther Rickert,Luyang Xiao,Lirong Chang,Shasha Wang,Peter Krost,Rui Zhang,Florian Weinberger

doi:10.1007/s10811-018-1709-6

Abstract

Diseases increasingly threaten aquaculture of kelps and other seaweeds. At the same time, protection concepts that are based upon application of biocides are usually not applicable, as such compounds would be rapidly diluted in the sea, causing ecological damage. An alternative concept could be the application of immune stimulants to prevent and control diseases in farmed seaweeds. We here present a pilot study that investigated the effects of oligoalginate elicitation on juvenile and adult sporophytes of Saccharina japonica cultivated in China and on adult sporophytes of Saccharina latissima cultivated in Germany. In two consecutive years, treatment with oligoalginate clearly reduced the detachment of S. japonica juveniles from their substrate curtains during the nursery stage in greenhouse ponds. Oligoalginate elicitation also decreased the density of endobionts and the number of bacterial cells on sporophytes of S. latissima that were cultivated on sea-based rafts. However, the treatment increased the susceptibility of kelp adults to settlement of epibionts (barnacles in Germany and filamentous algal epiphytes in China). In addition, oligoalginate elicitation accelerated the aging of S. japonica adults. Based upon these findings, oligoalginate elicitation could be a feasible way to provide “environmentally friendly” protection of kelp juveniles in nurseries. The same treatment causes not only beneficial, but also unwanted effects in adult kelp sporophytes. Therefore, it is not recommended as a treatment after the juvenile stage is completed. Future tests with other elicitors and other cultivated seaweed species may allow for the development of more feasible applications of targeted defense elicitation in seaweed aquaculture.

Highlights

IntroductionSome seaweed oligosaccharides derived from algal cell walls are designated as endogenous elicitors, since they can elicit algal immune responses (Potin et al. J Appl Phycol (2019) 31:1845–1854
Plants and seaweeds consist, in part, of specific polysaccharides that differ among taxonomic groups and play variousElectronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.Some seaweed oligosaccharides derived from algal cell walls are designated as endogenous elicitors, since they can elicit algal immune responses (Potin et al.J Appl Phycol (2019) 31:1845–18541999; Weinberger 2007)
We observed an elimination of associated bacteria and a reduced infection with algal endophytes in those S. latissima sporophyte thalli which were cultivated on sea-based rafts

Summary

Introduction

Some seaweed oligosaccharides derived from algal cell walls are designated as endogenous elicitors, since they can elicit algal immune responses (Potin et al. J Appl Phycol (2019) 31:1845–1854. Küpper et al (2001) found that an alginate-derived oligoguluronate could induce a defense response with a rapid, strong oxidative burst and a marked potassium efflux from elicited cells in the kelp Laminaria digitata. The same response was observed in sporophytes of other tested kelp species, including some members of the genus Laminaria, Saccharina latissima, Macrocystis pyrifera, Lessonia nigrescens, and Saccorhiza polyschides. In all these species, recognition of alginate oligosaccharides was involved in the natural and induced immunity against epiphytic bacteria and endophytes (Küpper et al 2002)

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