Exoproteome Analysis of the Seaweed Pathogen Nautella italica R11 Reveals Temperature-Dependent Regulation of RTX-Like Proteins

Abstract

Climate fluctuations have been linked to an increased prevalence of disease in seaweeds, including the red alga Delisea pulchra, which is susceptible to a bleaching disease caused by the bacterium Nautella italica R11 under elevated seawater temperatures. To further investigate the role of temperature in the induction of disease by N. italica R11, we assessed the effect of temperature on the expression of the extracellular proteome (exoproteome) in this bacterium. Label-free quantitative mass spectrometry was used to identify 207 proteins secreted into supernatant fraction, which is equivalent to 5% of the protein coding genes in the N. italica R11 genome. Comparative analysis demonstrated that expression of over 30% of the N. italica R11 exoproteome is affected by temperature. The temperature-dependent proteins include traits that could facilitate the ATP-dependent transport of amino acid and carbohydrate, as well as several uncharacterized proteins. Further, potential virulence determinants, including two RTX-like proteins, exhibited significantly higher expression in the exoproteome at the disease inducing temperature of 24°C relative to non-inducing temperature (16°C). This is the first study to demonstrate that temperature has an influence exoproteome expression in a macroalgal pathogen. The results have revealed several temperature regulated candidate virulence factors that may have a role in macroalgal colonization and invasion at elevated sea-surface temperatures, including novel RTX-like proteins.

Bacterial Communities Associated With Four Blooming Scyphozoan Jellyfish: Potential Species-Specific Consequences for Marine Organisms and Humans Health

“…Genus Nautella , identified in the umbrella of N. nomurai , was dominated by N. italica , an etiological agent of bleaching in the red alga Delisea pulchra ( Case et al, 2011 ; Gardiner et al, 2017 ; Hudson et al, 2018 ). The most abundant species of genus Acinetobacter , detected in the oral arms of C. nozakii , was A. schindleri , a human pathogen ( McGann et al, 2013 ; Jani et al, 2019 ).…”

Synergistic effects of temperature and light affect the relationship between Taonia atomaria and its epibacterial community: a controlled conditions study

“…Concerns are notably raised since lower health conditions and chemical defences caused by increasing temperature can result in a microbiota dysbiosis (Egan et al ., 2014; Egan and Gardiner, 2016; Minich et al ., 2018). More precisely, the development of opportunistic pathogens could be promoted through the activation of virulence factors (Case et al ., 2011; Fernandes et al ., 2011; Gardiner et al ., 2017).…”

High Potential for Secondary Metabolite Production of Paracoccus marcusii CP157, Isolated From the Crustacean Cancer pagurus

“…Bioactivity of the here tested Paracoccus strains extends from antibiosis over signaling to hemolysis, of which the latter has so far not been reported for members of this genus. Corresponding genes found in the CP157 genome are similar (>40%) to those of α-hemolysin ( hlyA ) and adenylate-cyclase toxin ( cyaA ) of pathogenic E. coli and Bordetella pertussis , respectively ( Gardiner et al, 2017 ). In both cases, the gene products are known to possess cytotoxic activity toward a broad range of eukaryotic cell types ( Ludwig and Goebel, 2006 ).…”