|Budget Amount *help
¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 1999 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1998 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1997 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Transcriptional regulation of laccase and cellulase mRNA were investigated for fruiting on the sawdust-based cultivation of Lentinula edodes.
(Materials and Methods)
1. Twelve spawn strains were examined in this study. KS-3, -4, -16, -23, -46, -56, -58, -60, -67, and -76 (wide-weather strains), KS-12 and -24 (cold weather strains).
2. The sawdust-based substrate cultivation was done according to the standard methods. Activities of laccase and cellulase were measured at the 7 different growth stages. The growth stages were defined to mycelial growth (90-days old), aggregate (94-days old), pin (98-days old), button (100-days old), veil break (102-days old), senescent (104-days old), and second flush (140-days old).
3. Moisture condition of the sawdust-based substrate was adjusted soaking treatment. The moisture condition was evaluated by the water potential (φ) values.
4. Transcriptional regulation of laccase and cellulase genes was measured by the RT-PCR method.
activities of laccase and cellulase and their transcriptional regulation were investigated at various growth stages in a sawdust-based substrate for Lentinula edodes. Changes of laccase and cellulase activities revealed a clear relationship with fruit body development stages. Laccase and cellulase activities were regulated at the level of gene transcription. The level of laccase mRNA was maximal at the fully colonized stage and declined during fruit body development. Cellulase mRNA began to accumulate at the pin (miniature fruit bodies) formation stage. Cellulase mRNA transcripts were maximally expressed at the veil-break stage of fruit body development. This tendency was clearer in the fruiting cultures with the wide-range-weather strains than in non-fruiting cold-weather strains. Transcription of laccase and cellulase genes was also affected by the water conditions of the sawdust-based substrate. Primordia initiation occurred when the water potential of the medium was high for rapid mRNA transcription by the mycelium. Less