Epiphytic bacteria on the Antarctic ice diatom Amphiprora kufferathii Manguin cleave hydrogen peroxide produced during algal photosynthesis

Abstract

The Antarctic ice diatom Amphiprora kufferathii Manguin is always accompanied by epiphytic bacteria in its natural habitat. To investigate the nature of this relationship, axenic cultures of A. kufferathii were obtained by ampicillin treatment. Diatom cultures without bacteria were less dense. The bacteria were shown to consume hydrogen peroxide produced by the diatom during photosysnthesis and algal photosynthesis after a hydrogen peroxide shock recovered faster in the presence of bacteria. Three proteobacterial strains isolated from a culture of A. kufferathii were phylogenetically affiliated with the alphaproteobacterial genus Sulfitobacter, the gammaproteobacterial genus Colwellia, and the genus Pibocella of the Bacteriodetes. Native protein gel electrophoresis and enzyme activity staining revealed the presence of superoxide dismutase and glutathione reductase in the isolated bacteria and in A. kufferathii cultures. Catalase was detected in bacterial extracts but not in axenic cultures of A. kufferathii. These observations indicate that the epiphytic bacteria make a significant contribution to the diatom's antioxidative defences. The relationship between the bacteria and A. kufferathii seems to be beneficial for both partners and enhances growth of Amphiprora in the sea ice.

Effect of bacteria on growth and biochemical composition of two benthic diatoms Halamphora coffeaeformis and Entomoneis paludosa

“…Bacteria can also have a detoxification role and help to the disappearance of toxic compounds derived from the algal metabolism (Hunken et al, 2008;Mouget et al, 1995). In particular the reduction of the oxidative stress linked to the photosynthetic activity of the diatom Amphiprora kufferathii was observed with bacteria affiliated to the alphaproteobacteria (Sulfitobacter), gammaproteobacteria (Colwellia) and bacteroidetes (Pibocella) (Hunken et al, 2008).…”

“…In particular the reduction of the oxidative stress linked to the photosynthetic activity of the diatom Amphiprora kufferathii was observed with bacteria affiliated to the alphaproteobacteria (Sulfitobacter), gammaproteobacteria (Colwellia) and bacteroidetes (Pibocella) (Hunken et al, 2008).…”

“…Microalgae can also be protected by detoxifying bacteria from some of the products they produced during growth, such as hydrogen peroxide produced during photosynthesis, for which bacterial cleavage reduces the oxidative stress. This detoxification was shown for Proteobacteria affiliated to the alphaproteobacteria genus Sulfitobacter, the gammaproteobacteria genus Colwellia, and the genus Pibocella of the Bacteriodetes (Hunken et al, 2008). Furthermore, aerobic bacteria (Pseudomonas diminuta and P. vesicularis) can reduce photosynthetic oxygen tension within the phycosphere, thereby creating favourable conditions for photosynthetic algal growth (Mouget et al, 1995).…”

“…on microalgal growth performance (Le Chevanton et al, 2013). Heterotrophic bacteria phyla commonly associated to diatom cultures are Proteobacteria and Bacteroidetes (Schäfer et al, 2002) and the main species belong to Alteromonas, Flavobacterium, Roseobacter, and Sulfitobacter genera (Grossart et al, 2005;Hunken et al, 2008;Kaczmarska et al, 2005;Sapp et al, 2007a;Sapp et al, 2007b;Sapp et al, 2007c). Some bacteria can improve microalgal growth through synergistic interactions (reviewed in Amin et al (2012)).…”

Tetraselmis suecica F&M‐M33 growth is influenced by its associated bacteria

“…This may occur through different mechanisms, among which nutrient regeneration, release of trace elements and vitamins (particularly vitamin B 12 ) or of stimulatory compounds, enrichment of CO 2 and consumption of excess O 2 , or scavenging of reactive oxygen species in the algal microenvironment (Mouget et al ., 1995; Croft et al ., 2005; Hünken et al ., 2008; Natrah et al ., 2014; Cooper and Smith, 2015; Fuentes et al ., 2016; Park et al ., 2017). Addition of selected bacterial strains in mass cultures has been shown to have a stabilizing effect, improving microalgal production reliability (Fukami et al ., 1997).…”