Saline-dependent regulation of manganese peroxidase genes in the hypersaline-tolerant white rot fungus Phlebia sp. strain MG-60.
The expression pattern of manganese peroxidases (MnPs) in nitrogen-limited cultures of the saline-tolerant fungus Phlebia sp. strain MG-60 is differentially regulated under hypersaline conditions at the mRNA level. When MG-60 was cultured in nitrogen-limited medium (LNM) containing 3% (wt/vol) sea salts (LN-SSM), higher activity of MnPs was observed than that observed in normal medium (LNM). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis demonstrated that two MnP isoenzymes were de novo synthesized in the culture of LN-SSM. Three MnP-encoding genes (MGmnp1, MGmnp2, and MGmnp3) were isolated by reverse transcription (RT)-PCR and rapid amplification of cDNA ends PCR techniques. The corresponding isozymes were identified by peptide mass fingerprinting analysis. MnP isozymes encoded by MGmnp2 and MGmnp3 were observed mainly in LN-SSM. Real-time RT-PCR analysis revealed high levels of MGmnp2 and MGmnp3 transcripts in LN-SSM 48 h after the addition of 2% NaCl. The induction of MnP production and the accumulation of gene transcripts by saline were well correlated in the presence of Mn(2+). However, in the absence of Mn(2+), there was no clear correlation between mnp transcripts levels and MnP activity, suggesting posttranscriptional regulation by Mn(2+).
Kamei
Ichiro
I
Department of Forest and Forest Products Sciences, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
Daikoku
Chieko
C
Tsutsumi
Yuji
Y
Kondo
Ryuichiro
R
D001487:Basidiomycota / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D018076:DNA, Complementary / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects*; D005800:Genes, Fungal; D007527:Isoenzymes / Q000235:genetics; D008345:Manganese / Q000378:metabolism; D013058:Mass Spectrometry; D009584:Nitrogen / Q000378:metabolism; D010449:Peptide Mapping; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D012331:RNA, Fungal / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012462:Saline Solution, Hypertonic / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D005656:Fungal Proteins; D007527:Isoenzymes; D012331:RNA, Fungal; D012333:RNA, Messenger; D012462:Saline Solution, Hypertonic; D008345:Manganese; D010544:Peroxidases; C051129:manganese peroxidase; D009584:Nitrogen