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

Abstract

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

Microcystins in Water: Detection, Microbial Degradation Strategies, and Mechanisms

“…Studies on the efficiency of MC removal by Mucor hiemalis showed that fungal intracellularly internalized MC-LR was broken down and biotransformed into less toxic MC-LR-GSH conjugates within 24 h of exposure [ 102 ]. Zeng et al [ 103 ] found that Pseudomonas flavus not only inhibited the growth of P. aeruginosa, but its metabolites were able to inhibit the synthesis of MCs.…”

Recent Advances in the Research on the Anticyanobacterial Effects and Biodegradation Mechanisms of Microcystis aeruginosa with Microorganisms

“…It has been reported that the fungus Trichaptum abietinum 1302BG can eliminate four cyanobacteria directly including M. aeruginosa FACH-918 and M. aeruginosa PCC 7806 in 48 h [106]. Some other fungi such as Trichoderma citrinoviride [6], Penicillium chrysogenum [97], Aureobasidium pullulans KKUY070 [98], Lopharia spadicea [99], Phanerochaete chrysosporium [100,101], Irpex lacteus T2b [102], Trametes versicolor F21a [107] and Bjerkandera adusta T1 [103] also show good inhibitory activities against M. aeruginosa. It has been stated that T. citrinoviride and A. pullulans have highly specific anticyanobacterial effects towards Microcystis spp.…”

“…The relative transcriptional level of some critical genes in cyanobacteria can be dramatically changed by anticyanobacterial microorganisms and substances, including genes related to the synthesis of photosystem reaction center proteins (PsaA, psaB, psbA1 and psbD1) [47,57], peptidoglycan synthesis (glmS), membrane proteins (ftsH), antioxidase (prx) [100], heat-shock proteins (grpE) [100], fatty acids (fabZ) [100], cyanotoxin microcystins (mcyA, mcyB, mcyC and mcyD) [83,97], the functions of cell division (ftsZ) [93], CO 2 fixation (rbcL) [61], and DNA repair (ftsH and recA) [2,5]. Researchers have reported that the tran-scription expressions of genes ftsZ, psbA1, and glmS are decreased by DBL that is isolated from P. noxius HN-1 [104] and bacilysin that secreted from B. amyloliquefaciens FZB42 [91].…”

“…Gene such as mcyB that are involved in microcystins synthesis are also inhibited by Penicillium spp. [97], the white-rot fungi P. chrysosporium [100,101] and P. noxius HN-1 [104]; moreover, both directly attack the anticyanobacterium (S. globisporus G9) [83] and indirectly attack anticyanobacteria (including S. amritsarensis HG-16 and Bacillus sp. AF-1) could inhibit microcystins synthesis [5,51].…”

Different Algicidal Modes of the Two Bacteria Aeromonas bestiarum HYD0802-MK36 and Pseudomonas syringae KACC10292T against Harmful Cyanobacteria Microcystis aeruginosa

“…To reduce this, extensive studies have been consistently conducted to develop an effective method to control this cyanobacterial bloom. Consequently, the various methods for physical (e.g., clay and ultrasound), chemical (e.g., copper sulfate, naphtoquinone derivates, and hydrogen peroxide), and biological (e.g., algicidal bacteria, fungi, and protozoa) controls have been developed [7][8][9][10]. Compared to physical and chemical controls, biological control was recognized as environmentally friendly technique for controlling this cyanobacterial bloom [11].…”