A novel thaumatin-like protein-encoding gene from Lentinula edodes, Tlg1, is involved in lentinan degradation during post-harvest preservation
Fecha
2006Versión
Acceso abierto / Sarbide irekia
Tipo
Contribución a congreso / Biltzarrerako ekarpena
Versión
Versión publicada / Argitaratu den bertsioa
Impacto
|
nodoi-noplumx
|
Resumen
Lentinan, which is a β-1, 3-linked-D-glucan with β-1, 6 branches isolated
as anti-tumor active-substance from Lentinula edodes, is purified from fresh
fruiting bodies and marketed for clinical use. However, it is known that
lentinan content decreases during post-harvest preservation as a result of increased
β-1, 3-glucanase activity. We isolated two exo-glucanase encoding
genes, exg1 and exg2 fro ...
[++]
Lentinan, which is a β-1, 3-linked-D-glucan with β-1, 6 branches isolated
as anti-tumor active-substance from Lentinula edodes, is purified from fresh
fruiting bodies and marketed for clinical use. However, it is known that
lentinan content decreases during post-harvest preservation as a result of increased
β-1, 3-glucanase activity. We isolated two exo-glucanase encoding
genes, exg1 and exg2 from L. edodes. Transcription level of the exg1 and exg2
gene was higher in the stipe than in the pileus of young fruiting bodies. This
suggests that the exg1 and exg2 are involved in stipe elongation in L. edodes.
We also isolated one endo-glucanase encoding gene, tlg1, from L. edodes. The
tlg1 gene had 1.0 kbp cDNA length, and encoded protein was estimated as
M.W. of 25 kDa and pI value of 3.48. Putative amino acid sequence of the
tlg1 displayed 43% identity to thaumatin-like (TL) proteins from Arabidopsis
thaliana. TLG1 had 16 cysteins conserved in TL-proteins. TL-protein is
pathogen related protein 5 in plant, and several TL-protein had endo-glucanase
activity. Previously, it is considered that TL-protein is unique in plant,
however, this research and recent genome sequence project revealed that similar
sequences to TL-proteins are conserved in filamentous fungi. We measured
β-1, 3-glucanase activity of L. edodes fruiting bodies after harvesting by
somogyi-melson method using laminarin as a substrate, and endo-β-1, 3-
glucanase activity by using AZCL-pachyman as a substrate. These revealed
that glucanase activity increased during post-harvest preservation. Transcription
level of the exg1 gene decreased, but the exg2 and tlg1 genes increased
during post-harvest preservation. Western blot analysis showed that EXG2
and TLG1 expression increased after harvesting. Purified EXG1 did not degrade
lentinan, but EXG2 and TLG1 degraded lentinan, therefore, we concluded
that the exg2 and tlg1 genes are involved in lentinan degradation during
post-harvest preservation. [--]
Materias
Lentinula edodes,
tlg1
Editor
Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Publicado en
Antonio G. Pisabarro and Lucía Ramírez (eds.): VI Meeting on Genetics and Cellular Biology of Basidiomycetes (GCBB-VI). Pamplona: Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2006.
Notas
Resumen del poster presentado al VI Meeting on Genetics and Cellular Biology of Basidiomycetes (GCBB-VI), organizado por y celebrado en la Universidad Pública de Navarra el 3-6 de junio de 2005.