SWEETタンパク質によって媒介されるサクラロース流出は,フロエム輸送の重要なステップとして,SWEETタンパク質によって媒介されるサクラロース流出です
Li-Qing Chen1, Xiao-Qing Qu, Bi-Huei Hou
1Carnegie Institution for Science, 260 Panama Street, Stanford, CA 94305, USA.
まとめ
研究者らは,SWEETサクラロース流出輸送体が糖をメソフィルからフローム細胞に移動するのに不可欠であることを発見しました. これは,植物糖の輸送とフロームの負荷の重要なステップを特定します.
科学分野:
- 植物生物学 植物生物学
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
背景:
- 植物は固定炭素を主にサクラロースとして輸送し,メソフィル細胞で合成され,分布のためにフロームに移動します.
- サクラホーズの合成部位からフロームへの移動と,アポプラズマへの流出を媒介する細胞の正確なメカニズムは不明である.
- サクラロースの流出は,サクラロース-H(+) (陽子) コトランスポーター (SUT) によるフローム負荷の前提条件である.
研究 の 目的:
- メソフィル細胞からフロームへのサクラロース輸送のメカニズムを解明する.
- サクラホーズのアポプラズマへの流入に関与する特定のトランスポーターを特定する.
- フローム・ロードにおける特定されたトランスポーターの役割を理解する.
主な方法:
- サクラロースの動きを監視するために光学サクラロースセンサーを使用しました.
- 特定のSWEET遺伝子 (AtSWEET11と12) に挿入された変異植物を生成した.
- AtSWEET11と12のローカライゼーションと機能をフロームロードで分析した.
主要な成果:
- SWEETサクラロース流出輸送体のサブファミリーを特定しました.
- AtSWEET11と12は,フローム細胞のプラズマ膜に局在していた.
- 機能的なAtSWEET11と12を欠いた変異植物は,フローム負荷の欠陥を示した.
- 2段階のメカニズムが明らかになった:SWEETを介したパレンキマ細胞からの輸出に続いて,シート要素-コンパニオン細胞複合体へのH(+) 結合輸入.
結論:
- SWEETトランスポーターは,パレンキマ細胞からのサクラホーズの流出に重要な役割を果たし,フロームの負荷を容易にします.
- この発見は,植物における光合成炭素の長距離輸送における重要なステップを明らかにしている.
- 細胞間サクラロースの輸送を制限すると,アポプラズマの炭素の利用可能性が制限され,病原菌感染を予防する可能性があります.
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