Nutrition-detoxification complex metabolism in lepidopteran larval midgut

2020 Fiscal Year Final Research Report

• Project/Area Number: 17H05029
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Bioorganic chemistry
• Research Institution: Kyoto University
• Principal Investigator: Yoshinaga Naoko 京都大学, 農学研究科, 助教 (40456819)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 鱗翅目幼虫 / 窒素代謝 / 解毒 / FACs / iridoids

Outline of Final Research Achievements

FACs, fatty acid-amino acid condensates in the gut of lepidopteran larvae, are involved in efficient nitrogen metabolism in larvae. The FACs biosynthetic enzymes in Spodoptera litura larvae are lepidopteran-specific carboxylesterases with unknown functions. By genome editing of the same species, we succeeded in generating a line lacking the FACs-degrading enzyme, L-ACY-1. These lines showed delayed growth compared to the wild type, and also their detoxification ability seemed to be reduced. The larvae neutralize gardenoside, a toxic substance found in gardenia leaves, by accumulating a large amount of β-alanine in the intestine. We found the induction was triggered by the glycoside glucose. The complex cross-link between nutrient metabolism and detoxification metabolism in the larval body was revealed.

Free Research Field

化学生態学

Academic Significance and Societal Importance of the Research Achievements

鱗翅目幼虫は特殊な窒素代謝系を獲得しており、窒素栄養価の低い植物を餌としながら窒素同化を効率的に行う。特に農業害虫では、棘や毒、営巣といった天敵に対する防御を一切せず、成長速度を最大化して、高密度に繁殖することで生存戦略とする種が多数見られる。この戦略では、食餌から吸収した栄養を成長・繁殖にどこまで投入できるかが鍵となっており、制約となりうるのが解毒にかかるコストである。この観点から窒素代謝と解毒代謝の直接的な関係を明らかにした研究は少なく、今後の植物保護とペストコントロールに重要な知見となった。