Algicidal Molecular Mechanism and Toxicological Degradation of Microcystis aeruginosa by White-Rot Fungi

Abstract

Current research on the inhibition of <i>Microcystis aeruginosa</i> growth is primarily focused on algae-lysing bacteria, and few studies have investigated the inhibitory mechanisms by which fungi affect it at the molecular level. A comparative analysis of the effects of <i>Phanerochaete chrysosporium</i> on the expression of the algal cell antioxidant protease synthesis gene <i>prx</i>, the biological macromolecule damage and repair genes <i>recA</i>, <i>grpE</i>, and <i>fabZ</i>, and the photosynthesis system-related genes <i>psaB</i>, <i>psbD1</i> and <i>rbcL</i>, as well as genes for algal toxin synthesis <i>mcyB</i>, were performed to elucidate the molecular mechanism of <i>Phanerochaete chrysosporium</i> against <i>Microcystis aeruginosa</i> cells. RT-qPCR technology was used to study the molecular mechanism of algal cell inhibition by <i>Phanerochaete chrysosporium</i> liquid containing metabolites of <i>Phanerochaete chrysosporium</i>, <i>Phanerochaete chrysosporium</i> supernatant and <i>Phanerochaete chrysosporium</i> inactivated via high temperature sterilization at the gene expression level. Compared with the control, the chlorophyll-a contents dropped, and the <i>recA</i>, <i>grpE</i>, <i>fabZ</i>, and <i>prx</i> increased, but the <i>psaB</i>, <i>psbD1</i>, <i>rbcL</i> and <i>mcyB</i> showed that they were significantly reduced, which indicated that <i>Phanerochaete chrysosporium</i> can not only effectively destroy algal cells, but they may also reduce the expression of the <i>Microcystis aeruginosa</i> toxin gene and significantly block the metabolic system underlying the growth of algal cells and the synthesis of microcystins.