Roles of microRNA on flower color patterning in floricultural plants including lilies

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02945
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 39030:Horticultural science-related
• Research Institution: Hokkaido University
• Principal Investigator: Yamagishi Masumi 北海道大学, 農学研究院, 准教授 (40210348)
• Co-Investigator(Kenkyū-buntansha): 中塚 貴司 静岡大学, 農学部, 准教授 (60435576)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 花の模様 / microRNA / アントシアニン / 遺伝子発現制御 / R2R3-MYB / PTGS

Outline of Final Research Achievements

Some Asiatic hybrid lily cultivars develop bicolor tepals, which consist of anthocyanin-pigmented upper halves and un-pigmented lower halves. MYB12 positively regulating anthocyanin biosynthesis is downregulated in the lower halves. Since the lily MYB12 mRNA harbored a binding site for microRNA828 (miR828), the involvement of miR828 in variable spatial accumulation of MYB12 transcripts was evaluated. In the bicolor tepals, mature miR828 was more highly accumulated in the lower halves than in the upper halves, and miR828-directed cleavage of MYB12 transcripts was observed predominantly in the lower halves. Moreover, the cleavage triggered the production of secondary siRNA from MYB12 transcripts, and the siRNAs were accumulated predominantly in the lower halves. Consequently, miR828 suppressed MYB12 transcript accumulation in the white region, and the miR828/MYB12 module participated in the development of bicolor patterns in lily flowers.

Free Research Field

園芸科学

Academic Significance and Societal Importance of the Research Achievements

(1) 花に模様ができるしくみとしてこれまでに主に、転写因子による空間特異的な転写調節、トランスポゾンの転移、CHS遺伝子のPost-Transcriptional Gene Silencingの3つが知られているが、microRNAによる模様形成は全く新しいしくみである（このしくみは花のモデル植物でも報告されていない）。(2) バイカラー形成の遺伝的な背景が明らかになり、今後のユリ育種の効率化に寄与する。(3) microRNAが関与する現象は環境の影響を受けやすいとされており、温度などにたいするmicroRNA蓄積量の変化を明らかにすれば、模様の大きさを一定にする栽培条件の改良につながる。