Regulatory mechanisms and physiological roles of programmed cell death in pith parenchyma of Gramineae crops

2020 Fiscal Year Final Research Report

• Project/Area Number: 17H05019
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Science in genetics and breeding
• Research Institution: The University of Tokyo
• Principal Investigator: Fujimoto Masaru 東京大学, 大学院農学生命科学研究科(農学部), 准教授 (60554475)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: イネ科作物 / ソルガム / 茎柔組織 / プログラム細胞死 / マスター転写因子

Outline of Final Research Achievements

Pith parenchyma cells store water in many plants. These cells are important for producing sugar and ethanol from the sugar juice of grass stems. In this study, we identified a gene, long referred to as D, in a promising energy grass, Sorghum bicolor, that is responsible for reducing stem water content. Sorghum varieties with functional D had stems enriched with dry, dead pith parenchyma cells, whereas those with non-functional D had stems enriched with juicy, living pith parenchyma cells. D encodes a NAC transcription factor, which activates the autolytic enzymes involved in programmed cell death of plants. These results suggest that D is the master transcriptional switch for executing programmed death of pith parenchyma cells in sorghum stems. Thus, identifying D will provide a new approach to breeding crops for sugar and ethanol production.

Free Research Field

栽培学

Academic Significance and Societal Importance of the Research Achievements

製糖・エネルギー作物における茎水分含量の増大は，糖やエタノール生産の原料に用いる茎搾汁液の生産量や生産効率の向上につながります．本研究の成果は，乾汁性決定遺伝子機能の調節を標的とした，糖やエタノール生産用作物の効率的な品種改良や，新たな資源作物開発への道を拓くものとして期待されます．また，茎柔組織の大規模なプログラム細胞死は，イネ科作物のみならず，広範の植物種で観察される現象であり，本研究の成果は，未だ不明な点の多い，その生理的意義や制御機構の理解に大きく貢献するものです。