Development of ploidy diversification methods utilizing artificially induced unreduced male gametes

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K06035
• 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: University of Miyazaki
• Principal Investigator: Hirano Tomonari 宮崎大学, 農学部, 准教授 (80455584)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 重複受精 / 胚発生 / 重イオンビーム / 花粉 / 雄性配偶子

Outline of Final Research Achievements

In this study, we analyzed effects of male gametes of Cyrtanthus mackenii (Amaryllidaceae) irradiated with heavy-ion beams, a type of radiation, on fertilization. Two types of embryo sacs with an embryo and endosperm and with
an egg cell or an undivided zygote and endosperm were observed. Furthermore, the embryos and endosperm showed various DNA contents. We attempted ovule culture to induce plantlet from the distinctive embryo and endosperm for breeding. We examined the ovule culture conditions, and plant regeneration and germination from the embryos and callus formation from the endosperm were confirmed. These results show the possibility of plant regeneration from the endosperm. In the ovules derived from heavy-ion irradiated pollen, callus and shoot formation were also observed by the ovule culture but no plant regeneration was observed. Therefore, further investigation of irradiation conditions and plant regeneration conditions is required.

Free Research Field

植物遺伝育種学

Academic Significance and Societal Importance of the Research Achievements

植物の雄性配偶子におけるDNA損傷応答およびそれら損傷の受精への影響はこれまでに詳細な解析が行われておらず、本研究の成果は植物の受精機構を理解するうえで重要な知見となる。花粉への放射線照射は、これまでにも半数体獲得等の目的で品種改良技術として用いられてきたが、本研究では重イオンビームの放射線としての特徴を活かすことで迅速に倍数性を多様化する新たな品種改良技術として利用することが可能であることが示された。