ハマササゲがもつ”最強”の耐塩性機構が明らかに~作物の耐塩性開発に期待~

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2025-03-11 農研機構,量子科学技術研究開発機構,筑波大学,東京大学

ハマササゲがもつ”最強”の耐塩性機構が明らかに~作物の耐塩性開発に期待~
図1.​アズキ、ナガバハマササゲ(河川型・海浜型)およびハマササゲのナトリウム蓄積様式および特性情報​

農研機構、量子科学技術研究開発機構、筑波大学、東京大学の研究グループは、アズキの近縁種であるハマササゲが持つ高い耐塩性のメカニズムを解明しました。ハマササゲは、根からの高いナトリウム(Na)排出能力と、根にNaを透過させないバリアを形成する2つの機構を持っています。さらに、根からのNa排出は昼間に活発で夜間に休止する日周性を示し、これらの特性は2つの遺伝子の発現パターンによって説明できることが明らかになりました。これらの知見は、今後の耐塩性作物の開発に活用できると期待されます。

<関連情報>

ヒメツリガネゴケのNa+排除能力を支える多層アポプラスティックバリア Multi-layered apoplastic barrier underlying the ability of Na+ exclusion in Vigna marina

Fanmiao Wang, Keitaro Tanoi, Takaki Yamauchi, Ken Naito
Plant and Cell Physiology  Published:07 January 2025
DOI:https://doi.org/10.1093/pcp/pcaf005

Abstract

Soil salinization and ground water depletion are increasingly constraining crop production. Identifying useful mechanisms of salt tolerance is an important step toward the development of salt-tolerant crops. Of particular interest are mechanisms that are present in crop wild relatives, as they may have greater stress tolerance than crop species. The coastal species Vigna marina is one of the promising plant resources for salt tolerance. Vigna luteola is another wild species with diverse habitats, including seaside and riverbank, hereafter V. luteola-beach and V. luteola-river, respectively. By comparative transcriptome and histological analyses, this study elucidated one important aspect of how V. marina achieves an extraordinary ability to suppress Na+ uptake. Under salt stress, V. marina specifically upregulated genes involved in Casparian strip formation and developed a multi-layered lignified apoplastic barrier around endodermis, whereas V. luteola-beach formed typical, band-like Casparian strips and V. luteola-river formed only spot-like Casparian strips. As such, the ability of developing apoplastic barrier strongly correlated with those of suppressing Na+ uptake. The disruption of lignified barrier led to a dramatic increase of Na+ allocation to the shoot in V. marina, which was manifested in leaf etiolation and burning. Interestingly, despite the presence of reinforced apoplastic barrier, V. marina maintained the transport of essential ions including K+, Mg2+, and Ca2+. This study shows that the multi-layered Casparian strip-like structure plays an important role in salt tolerance.

生物工学一般
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