Plasma Membrane Localization and Potential Endocytosis of Constitutively Expressed XA21 Proteins in Transgenic Rice
Plasma Membrane Localization and Potential Endocytosis of Constitutively Expressed XA21 Proteins in Transgenic Rice
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转基因水稻中组成型表达的 XA21 蛋白的质膜定位和潜在的内吞作用
DOI：
10.1093/mp/ssq038
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发表时间：
2010-09-01
期刊：
影响因子：
27.5
通讯作者：
He, Zu-Hua
中科院分区：
文献类型：
--
作者：
Chen, Fang;Gao, Ming-Jun;He, Zu-Hua
水稻模式识别受体（PRR）XA 21赋予小种特异性抗性，在叶片感染白叶枯病Xathomonasarpv。Xoo），并且当用其天然启动子表达或在原生质体中过表达时显示主要定位于内质网（ER）。然而，蛋白质是否仍然是ER-定位在完整的细胞时，过表达仍有待确定。在这里，我们表明，XA 21，其激酶死亡突变体XA 21 P（K736 EP），和三重自磷酸化突变体XA 21 P（S686 A/T688 A/S699 A）的GFP融合主要定位于质膜（PM）时，在完整的转基因水稻细胞过表达，并定位于ER的转基因原生质体。组成型表达野生型XA 21或其GFP融合蛋白的转基因植株在成株期和苗期均表现出对Xoo的小种特异性抗性。XA 21和XA 21 P（K736 EP）可能通过SCAMP阳性的早期内体区室内化到原生质体中，表明XA 21可能被内吞以启动病原菌感染过程中的抗性反应。我们还建立了一个根感染系统，并证明XA 21也介导种族特异性的抗性反应Xoo在根中。我们目前的研究提供了一个深入了解XA 21介导的抗性的性质和一个实用的方法，使用根细胞系统，以进一步剖析PRR的细胞信号在水稻Xoo相互作用。
The rice pattern recognition receptor (PRR) XA21 confers race-specific resistance in leaf infection by bacterial blight Xathomonas oryzae pv. oryzae (Xoo), and was shown to be primarily localized to the endoplasmic reticulum (ER) when expressed with its native promoter or overexpressed in the protoplast. However, whether the protein is still ER-localization in the intact cell when overexpressed remains to be identified. Here, we showed that XA21, its kinase-dead mutant XA21P(K736EP), and the triple autophosphorylation mutant XA21P(S686A/T688A/S699A) GFP fusions were primarily localized to the plasma membrane (PM) when overexpressed in the intact transgenic rice cell, and also localized to the ER in the transgenic protoplast. The transgenic plants constitutively expressing the wild-type XA21 or its GFP fusion displayed race-specific resistance to Xoo at the adult and seedling stages. XA21 and XA21P(K736EP) could be internalized probably via the SCAMP-positive early endosomal compartment in the protoplast, suggesting that XA21 might be endocytosed to initiate resistance responses during pathogen infection. We also established a root infection system and demonstrated that XA21 also mediated race-specific resistance responses to Xoo in the root. Our current study provides an insight into the nature of the XA21-mediated resistance and a practical approach using the root cell system to further dissect the cellular signaling of the PRR during the rice-Xoo interaction.