UC San Diego

Now more than ever the growth of algal farming for biofuels and bioproducts as more sustainable alternatives to fossil fuels and its derivatives has created a need for more efficient cultivation strategies. Unfortunately, however, while open-air ponds are the most cost-effective way to grow the microalgae that are used for biofuels and bioproducts, they are also more susceptible to invasion by predators. Because of this, strategies for crop protection must be developed in order to minimize this pressure from grazers. A mutant of the model cyanobacterium Synechococcus elongatus PCC 7942, called AMC 1908, which lacks the wzm (Synpcc7942_1126) gene for O-antigen synthesis, is resistant to grazing by amoebae, which can be algal pool predators. In order to determine the molecular mechanisms that could be behind this resistance, the outer membrane proteins of S. elongatus PCC 7942 and AMC 1908 were compared via SDS-PAGE analysis and proteomics. As expected, the protein compositions of S. elongatus PCC 7942 and AMC 1908 outer membranes differed quite substantially. Additionally, transport system substrate-binding protein IdiA (Synpcc7942_2175) was found to be more abundant in the mutant AMC 1908 when compared to the wild-type PCC 7942. This protein could be contributing to S. elongatus AMC 1908’s resistance to grazing by amoebae, but only further testing can confirm this.