Evolution of host plant selection in the mulberry silkworm and other bombycoids

2015 Fiscal Year Final Research Report

• Project Area: Genetic bases for the evolution of complex adaptive traits
• Project/Area Number: 22128004
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Biological Sciences
• Research Institution: The University of Tokyo
• Principal Investigator: Shimada Toru 東京大学, 農学生命科学研究科, 教授 (20202111)
• Co-Investigator(Kenkyū-buntansha): Katsuma Susumu 東京大学, 大学院農学生命科学研究科, 准教授 (20378863) ; Daimon Takaaki 独立行政法人農業生物資源研究所, 昆虫科学研究領域, 主任研究員 (70451846) ; Kiuchi Takashi 東京大学, 大学院農学生命科学研究科, 助教 (60622892)
• Research Collaborator: Daimon Takaaki 東京大学, 大学院農学生命科学研究科, 助教 ; Fujii Tsuguru 日本学術振興会, 特別研究員PD ; Kiuchi Takashi 東京大学, 大学院農学生命科学研究科, 助教 ; Wang Huabing 日本学術振興会, 外国人特別研究員 ; Katsuma Susumu 東京大学, 大学院農学生命科学研究科, 准教授
• Project Period (FY): 2010-04-01 – 2016-03-31
• Keywords: 複合適応形質 / 共進化 / 比較ゲノム / トランスクリプトーム / 発現制御

Outline of Final Research Achievements

The larval food habits of bombycoid silkmoths have been presumably evolved from Ficus feeding to Morus (mulberry) one. The latex of mulberry contains sugar-mimic alkaloidal toxins, and the mulberry feeders (Bombyx etc.) must overcome the toxicity. The polyphagous mutants, Bt and spli were analyzed to understand the genetic basis of mulberry feeding in Bombyx. We found that a transcription factor gene (Bmacj6) was defective in the mutants. The expression of the genes encoding olfactory receptors and so on was over- or mis-expressed in sensory organs of the mutants. On the other hand, we found that the major sucrases were enzymatically more tolerant to the mulberry alkaloids in Bombyx than in non-mulberry bombycoids. The results of RNA-seq, genome sequencing, and genome editing suggested that the sucrases and other enzymes influenced by the sugar-mimic alkaloids have evolved quantitatively and qualitatively so that the mulberry-feeding species have overcome the toxicity.

Free Research Field

昆虫遺伝学