2026-04-16 東京大学
本研究は、東京大学の研究チームが、植物ウイルスの宿主範囲を決定する分子機構を解明した成果である。アブラナ科植物がポテックスウイルスに感染しにくい理由として、抵抗性遺伝子JAX1の存在が鍵であることを示した。JAX1はウイルス増殖に必要なタンパク質を阻害し、その効果は遺伝子の有無（DNA）、発現（RNA）、機能（タンパク質）の3段階で制御される。さらに、JAX1を欠失させると本来感染しない植物にもウイルスが感染することが確認された。これにより、非宿主抵抗性の主要因が特定され、植物とウイルスの共進化理解や耐病性作物の開発に重要な知見を提供する。
JAX1による宿主範囲制御メカニズム
＜関連情報＞
- https://www.a.u-tokyo.ac.jp/topics/topics_20260416-2.html
- https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.71145
抗ウイルス性のジャカリン様レクチン遺伝子は、アブラナ科植物におけるポテックスウイルスの非宿主抵抗性と宿主決定に寄与する An antiviral jacalin-like lectin gene contributes to nonhost resistance and host determination of potexviruses among Brassicaceae
Takumi Suzuki, Kazuya Ishikawa, Akira Yusa, Nozomu Iwabuchi, Kan Kimura, Tetsuya Yoshida, Mari Ota, Masato Suzuki, Masanobu Nishikawa, Kensaku Maejima, Shigetou Namba, Yasuyuki Yamaji
New Phytologist Published: 16 April 2026
DOI:https://doi.org/10.1111/nph.71145
Summary
- Plant resistance influences the host range of pathogens; however, the mechanism driving this influence remains poorly understood. Brassicaceae species are not natural hosts of potexviruses, for reasons that have not yet been determined.
- This study investigated the molecular basis of nonhost resistance (NHR) to potexviruses in the Brassicaceae, focusing on the non-nucleotide-binding leucine-rich repeat (NLR) resistance gene JACALIN-TYPE LECTIN REQUIRED FOR POTEXVIRUS RESISTANCE1 (JAX1).
- We found that JAX1 is a Brassicaceae-specific conserved gene that has been lost or pseudogenized in some species, and duplicated in others. Most JAX1 orthologs from diverse Brassicaceae species effectively inhibit plantago asiatica mosaic virus (PlAMV) accumulation, indicating that antiviral activity is conserved among the Brassicaceae. However, we demonstrated that some Brassicaceae plants in which JAX1 expression was not detected allow local or systemic viral infection. Quadruple knockout of JAX1 genes via gene editing in Sisymbrium irio, a nonhost of PlAMV, led to loss of resistance and potexvirus susceptibility in this species.
- These results clearly indicate that JAX1 represents one layer of multi-layer NHR against potexviruses in the Brassicaceae, shedding light on the pivotal role of non-NLR antiviral resistance in shaping the host range of these plant viruses.
