Novel pink-spot disease in North American kelp nurseries
摘要
Cultivation of kelp and other macroalgae is a growing industry in North America. In the well established macroalgal growing regions in Asia and Africa, macroalgal disease cause crop losses, placing a significant economic burden on growers. As kelp cultivation intensifies in North America, disease prevalence is expected to increase in tandem. Here, we describe the prevalence and bacterial community associated with a novel disease of kelp in the land based nursery stage that is characterized by bright pink spots, termed pink-spot disease. With input from the kelp-growing community through an online survey, we show that pink-spot disease has been widely observed in Canada and the United States on nursery cultivation spools of the kelps Saccharina latissima, Alaria marginata, Nereocystis luetkeana, and Macrocystis tenuifolia. We conducted 16S rRNA amplicon sequencing in 2021 and 2022 to investigate the causative agent of pink-spot disease and associated bacterial community changes on infected S. latissima (sugar kelp) spools in one nursery. Our data in both years showed that a member of the genus Algicola is enriched on visibly diseased spool regions compared to asymptomatic spool regions and may be the causative agent of pink-spot disease. Visible disease is associated with an altered bacterial community, but community change is not consistent acorss years. As macroalgal cultivation continues to intensify in North America monitoring the emergence and distribution of diseases will play an important role in managing disease and mitigating the associated economic burden.