Estimating adaptive differentiation between two varieties of the genus Thujopsis to Pacific side / Japan Sea side climate based on cold tolerance characteristics

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K14494
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 40010:Forest science-related
• Research Institution: Forest Research and Management Organization
• Principal Investigator: Inanaga Michiko 国立研究開発法人森林研究・整備機構, 森林総合研究所 林木育種センター, 主任研究員 等 (30757951)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: アスナロ / ヒノキアスナロ / 産地試験 / 低温順化 / 発現解析 / 糖分析

Outline of Final Research Achievements

Genus Thujopsis is endemic to Japan and consists of two varieties: T. dolabrata var. dolabrata, which is distributed mainly on the Pacific side, and T. dolabrata var. hondae, which is distributed mainly on the Sea of Japan side. Testing the hypothesis that there is a difference in winter cold tolerance between the two varieties, no difference was detected from November to early March during cold acclimation, thus rejecting the initial hypothesis. On the other hand, T. dolabrata var. dolabrata presented slightly higher cold tolerance in September-October and late March, suggesting that local adaptation to the provenance may occur at the preacclimation and the deacclimation stage. Sugar content analysis did not show any difference among the provenances. In addition, a T. dolabrata cDNA database with detailed annotations was developed for future use of comparison by expressed genes.

Free Research Field

森林遺伝学

Academic Significance and Societal Importance of the Research Achievements

冬季の耐寒性と糖含有量に変種間差が見られなかったことから、両変種の分化は冬季の低温に対する適応に起因するという仮説は否定された。一方、低温に順化していない期間の耐寒性にわずかな差が見られたことから、アスナロ属の変種の分化には仮説と異なる環境要因への適応、もしくは集団の隔離等の歴史的経緯が関わっている可能性が示された。本研究で整備されたcDNAデータベースは、今後多様なアスナロ属の遺伝学的研究、ひいては育種等に応用することができる。