Advances in Microbiology > Vol.5 No.2, February 2015

Avi Matityahu^1,2, Aya Sitruk¹, Yitzhak Hadar³, Paula A. Belinky^1*

¹Tel Hai Academic College, Kiryat Shmona, Israel.
²Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, Israel.
³Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.

The lignin peroxidase (LIP) production and regulation, in manganese ions (Mn²⁺) deficient cultures of the white rot fungus Phanerochaete chrysosporium, is still not clearly understood. Mn²⁺ deficiency is correlated to low levels of manganese containing superoxide dismutase (MnSOD). In this work, we show that despite the low activity level of MnSOD in Mn²⁺-deficient cultures, the presence of H₂O₂ is essential for the expression of the lip-H2 gene, which encodes for the major LIP isoenzyme produced (LIP-H2). Thus, the H₂O₂ present in Mn²⁺-deficient cultures is probably produced by other mechanisms rather than dismutation of superoxide ions by MnSOD. Glyoxal oxidase gene (glox) expression was significantly higher than MnSOD (MnSOD1) and cellobiose dehydrogenase (cdh1) expression in Mn²⁺-deficient cultures, indicating its clear involvement in H₂O₂ production in those cultures. Glyoxal oxidase may compensate the absence of MnSOD activity in Mn²⁺-deficient cultures. The high levels of reactive oxygen species (ROS) needed for the enhancement of LIP expression in Mn²⁺-deficient cultures were not directly correlated to the protein kinase C (PKC) activity involved in signal transduction pathway. High level of oxidative stress was observed in MnSOD silenced mutants, grown in the presence of Mn²⁺, indicating that oxidative stress in Mn²⁺-deficient cultures was caused by low levels of MnSOD rather than the deficiency in Mn²⁺. The results of this work can further contribute to the understanding of LIP regulation in Mn²⁺-deficient cultures.

ROS, GLOX, MnSOD, PKC, lip-H2 Induction

Matityahu, A. , Sitruk, A. , Hadar, Y. and Belinky, P. (2015) Factors Affecting the Induction of Lignin Peroxidase in Manganese-Deficient Cultures of the White Rot Fungus Phanerochaete chrysosporium. Advances in Microbiology, 5, 83-92. doi: 10.4236/aim.2015.52009.