Lentinula edodes tlg1 Encodes a Thaumatin-Like Protein That Is Involved in Lentinan Degradation and Fruiting Body Senescence
- 28 April 2006
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 141 (2), 793-801
- https://doi.org/10.1104/pp.106.076679
Abstract
Lentinan is an antitumor product that is purified from fresh Lentinula edodes fruiting bodies. It is a cell wall component, comprising β-1,3-glucan with β-1,6-linked branches, which becomes degraded during postharvest preservation as a result of increased glucanase activity. In this study, we used N-terminal amino acid sequence to isolate tlg1, a gene encoding a thaumatin-like (TL) protein in L. edodes. The cDNA clone was approximately 1.0 kb whereas the genomic sequence was 2.1 kb, and comparison of the two indicated that tlg1 contains 12 introns. The tlg1 gene product (TLG1) was predicted to comprise 240 amino acids, with a molecular mass of 25 kD and isoelectric point value of 3.5. The putative amino acid sequence exhibits approximately 40% identity with plant TL proteins, and a fungal genome database search revealed that these TL proteins are conserved in many fungi including the basidiomycota and ascomycota. Transcription of tlg1 was not detected in vegetative mycelium or young and fresh mushrooms. However, transcription increased following harvest. Western-blot analysis demonstrated a rise in TLG1 levels following harvest and spore diffusion. TLG1 expressed in Escherichiacoli and Aspergillus oryzae exhibited β-1,3-glucanase activity and, when purified from the L. edodes fruiting body, demonstrated lentinan degrading activity. Thus, we suggest that TLG1 is involved in lentinan and cell wall degradation during senescence following harvest and spore diffusion.Keywords
This publication has 40 references indexed in Scilit:
- Plant stress proteins of the thaumatin‐like family discovered in animalsFEBS Letters, 2004
- Crystal structure of tobacco PR-5d protein at 1.8 Å resolution reveals a conserved acidic cleft structure in antifungal thaumatin-like proteinsJournal of Molecular Biology, 1999
- New insights into the mechanisms of fungal pathogenesis in insectsTrends in Microbiology, 1996
- CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choiceNucleic Acids Research, 1994
- Zeamatin, an antifungal protein from maize with membrane-permeabilizing activityJournal of General Microbiology, 1990
- Differences in wall structure between substrate hyphae and hyphae of fruit-body stipes in Agaricus bisporusMycological Research, 1990
- Carnivorous MushroomsScience, 1984
- Autolysis in vitro of the Stipe Cell Wall in Coprinus macrorhizusMicrobiology, 1982
- Chemical and morphological characterization of the hyphal wall surface of the basidiomycete Schizophyllum CommuneBiochimica et Biophysica Acta (BBA) - General Subjects, 1972
- Inhibition of Mouse Sarcoma 180 by Polysaccharides from Lentinus edodes (Berk.) Sing.Nature, 1969