Role of xylem parenchyma and bundle sheath cells in rice under salt stress

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02175
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 39020:Crop production science-related
• Research Institution: Kindai University
• Principal Investigator: Yamane Koji 近畿大学, 農学部, 教授 (50580859)
• Co-Investigator(Kenkyū-buntansha): 大井 崇生 名古屋大学, 生命農学研究科, 助教 (60752219)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: イネ / 塩ストレス / 三次元再構築 / 維管束鞘細胞 / 維管束柔細胞

Outline of Final Research Achievements

In this study, the salt-sensitive Nipponbare and salt-tolerant variety Pokkali were used to investigate salt adaptive mechanisms focused on bundle sheath cells and xylem parenchyma cells. After the treatment with 100 mM NaCl for 4 days, the uppermost expanded leaves were fixed, and then, around 1500 serial sections were cut at 150 nm intervals to three-dimensionally analyze the two cells. In Pokkali, the changes in the ultrastructure of organelles such as plastids and mitochondria were not observed. In Nipponbare, however, the number of mitochondria increased three-fold and the volume ratio of mitochondria in bundle sheath cells was increased. These results suggest that bundle sheath cells in Nipponbare could play an important role to stop sodium influx into mesophyll cells by producing ATP in mitochondria under salt stress.

Free Research Field

植物超微形態学

Academic Significance and Societal Importance of the Research Achievements

これまでイネの維管束鞘細胞の役割は明確になっていなかったが、塩ストレス下で細胞内のミトコンドリアが増加していたことから、塩の流入を食い止める役割が示唆され、今後のイネ耐塩性向上に向けて新奇の方策を示唆できた点が学術的に大きいと考えられる。さらに、本研究において、ウルトラミクロトームと卓上走査型電子顕微鏡を用いた細胞内観察と取得した画像を用いた三次元解析が可能となった。これまで特殊な装置であるSerial Block Face-Scanning Electron Microscopeなどが用いられてきたが、汎用機器での解析が可能となったのは、今後の学術的意義として大きいと考えられる。