Sequencing and quantifying plastid DNA fragments stored in sapwood and heartwood of Torreya nucifera

Abstract

The selection of wood species and the styles of sculpture play key roles in the characterization of Buddhist statues. After Jianzhen, a Chinese Buddhist monk, visited Japan in the mid-eighth century, wood of the genus Torreya had been frequently used to produce single-bole statues. Establishing measures for the accurate identification of wood in the genus Torreya is effective for investigating the drastic change in the production of statues during this period. Analyzing the plastid deoxyribonucleic acid (DNA) fragments extracted from wood is considered helpful in the identification of species in the same genus. This study analyzed the sequences and residual amounts of plastid DNA fragments in the wood of Torreya nucifera. Nucleotide substitutions in the plastid DNA were clearly identified between T. nucifera and the species distributed in China, indicating that the wood of Torreya sp. can be discriminated based on the plastid DNA sequences. DNA polymorphism analyses revealed sequence diversity for the intergenic spacers on the T. nucifera plastid DNA. A series of polymerase chain reaction (PCR) analyses demonstrated that the plastid DNA fragments with a length of approximately 100 bp could be amplified from the residual DNA extracted from the T. nucifera sapwood with longer elapsed years after cutting. Therefore, an identification of wood species in the genus Torreya based on their plastid DNA is considered to be one of the most effective measures taken in the study regarding the historical changes of Buddhist statues.