Elucidation of the mechanism of pungency reduction by structural mutation of pAMT gene and its application to chili pepper breeding

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K05618
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 39030:Horticultural science-related
• Research Institution: Kyoto University (2019-2021); Okayama University (2018)
• Principal Investigator: Tanaka Yoshiyuki 京都大学, 農学研究科, 准教授 (20704480)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: トウガラシ / 辛味 / カプサイシノイド / トランスポゾン

Outline of Final Research Achievements

Pungency is an important trait of pepper fruits. Preferences for pungency differ among countries, regions, and uses, and breeding techniques that can control pungency level are needed. In this study, we analyzed the putative aminotransferase (pAMT) gene in capsaicinoid biosynthetic pathway, and identified multiple leaky alleles involving transposon insertion. We also analyzed the mechanism underlying reduction of pungency level, and found that the insertion of a transposon in the intron caused aberrant splicing, and that reduction level in pungency depend on the slight difference in the position of the transposon. Furthermore, we have demonstrated that allelic variation in pAMT would be useful to adjust pungency level by introducing different mutant alleles in backcrossing program.

Free Research Field

園芸科学

Academic Significance and Societal Importance of the Research Achievements

これまでの辛味育種は、カプサイシイド含量の異なるトウガラシを交雑し、その後代で偶然生じたちょうど良い辛味の個体を選抜するという手法で行われてきた。この育種法では、多数の遺伝子間での相互作用のために、育種家の目的通りの辛味をつくることが困難でだった。本研究を通して様々なpAMTタイプが発見されてきたことにより、育種開始前にpAMTのタイプを機能型か機能欠損型か、それともleaky型かを選択し、遺伝子マーカーを利用することで、どの程度まで辛味を抑えるかを計画的かつ効率的に進めることが可能になるだろう。