The OsABCI7 Transporter Interacts with OsHCF222 to Stabilize the Thylakoid Membrane in Rice
The OsABCI7 Transporter Interacts with OsHCF222 to Stabilize the Thylakoid Membrane in Rice
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OsABCI7转运蛋白与OsHCF222相互作用稳定水稻类囊体膜
DOI：
10.1104/pp.20.00445
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发表时间：
2020-09-01
期刊：
影响因子：
7.4
通讯作者：
Wu, Jian-Li
中科院分区：
文献类型：
--
作者：
He, Yan;Shi, Yongfeng;Wu, Jian-Li
类囊体膜是植物体内高度复杂的膜系统，在光合机构的生物发生和植物发育中起着至关重要的作用。然而，参与叶绿体发育的遗传因素及其与细胞内代谢物的关系在很大程度上是未知的。本研究鉴定了一个水稻（Oryza sativa）变色和坏死叶片1 （cnl1）突变体，基于图谱的克隆显示，atp结合盒转运体I家族成员7 （OsABCI7）的单碱基替换和6 bp的缺失导致叶片变色和坏死，并伴有类囊体膜降解、叶绿素分解、光合作用损伤和细胞死亡。此外，OsABCI7在较低温度下可诱导表达，严重影响了cnl1叶绿体发育，黄化的cnl1幼苗在光照条件下无法恢复正常的绿色状态。功能互补和过表达表明OsABCI7可以挽救cnl1的褪绿和坏死表型。OsABCI7与高叶绿素荧光222 （OsHCF222）相互作用，调节细胞活性氧（ROS）稳态，维持类囊体膜的稳定性。OsABCI7定位于类囊体膜，而OsHCF222定位于内质网和叶绿体。外源施用抗坏血酸通过增加叶绿素含量和减轻活性氧胁迫来缓解cnl1的黄叶表型。与cnl1不同，CRISPR/ cas9介导的OsHCF222敲除系显示叶片褪绿，但幼苗致死。我们的研究结果揭示了水稻中ABC转运体的功能，特别是ROS稳态与类囊体膜稳定性之间的关系。
The thylakoid membrane is a highly complex membrane system in plants and plays crucial roles in the biogenesis of the photosynthetic apparatus and plant development. However, the genetic factors involved in chloroplast development and its relationship with intracellular metabolites are largely unknown. Here, a rice (Oryza sativa) chlorotic and necrotic leaf1 (cnl1) mutant was identified and map-based cloning revealed that a single base substitution followed by a 6-bp deletion in the ATP-binding cassette transporter I family member7 (OsABCI7) resulted in chlorotic and necrotic leaves with thylakoid membrane degradation, chlorophyll breakdown, photosynthesis impairment, and cell death in cnl1. Furthermore, the expression of OsABCI7 was inducible under lower temperatures, which severely affected cnl1 chloroplast development, and etiolated cnl1 seedlings were unable to recover to a normal green state under light conditions. Functional complementation and overexpression showed that OsABCI7 could rescue the cnl1 chlorotic and necrotic phenotype. OsABCI7 interacted with HIGH CHLOROPHYLL FLUORESCENCE222 (OsHCF222) to regulate cellular reactive oxygen species (ROS) homeostasis for thylakoid membrane stability. OsABCI7 localized to thylakoid membranes, while OsHCF222 targeted to endoplasmic reticulum and chloroplasts. Exogenous application of ascorbic acid eased the yellowish leaf phenotype by increasing chlorophyll content and alleviating ROS stress in cnl1. Unlike cnl1, the CRISPR/Cas9-mediated OsHCF222 knockout lines showed chlorotic leaves but were seedling lethal. Our results provide insight into the functions of ABC transporters in rice, especially within the relationship between ROS homeostasis and stability of thylakoid membranes.