中国科学院分子植物科学卓越创新中心何祖华等研究人员合作发现，PRA-Rab运输机制调节水稻NLR免疫受体质膜微区锚定和抗爆性。相关论文于2024年12月9日在线发表在《科学通报》杂志上。

研究人员表示，核苷酸结合富亮氨酸重复（NLR）受体在植物中，介导病原效应子触发的免疫反应（ETI），而一类NLR受体被假设在质膜（PM）上发挥作用。然而，NLR的运输和质膜递送在免疫反应中的调控机制仍大量未知。水稻NLR受体PigmR对稻瘟病真菌Magnaporthe oryzae具有广谱抗性。

研究人员报告了一种PRA（已烯基化Rab受体）蛋白PIBP4（PigmR-INTERACTING和BLAST RESISTANCE PROTEIN 4），与PigmR及Rab GTP酶的活跃形式OsRab5a相互作用，从而将部分PigmR加载到靶向质膜微区的运输囊泡上。微区定位的PigmR与小GTP酶OsRac1相互作用并激活它，触发活性氧信号传导和超敏反应，进而启动对稻瘟病感染的免疫反应。

因此，该研究发现了一种此前未知的机制，通过PRA-Rab蛋白递送中心来确保ETI，将膜运输机制与植物中NLR的功能和免疫激活联系起来。

附：英文原文

Title: A PRA-Rab trafficking machinery modulates NLR immune receptor plasma membrane microdomain anchoring and blast resistance in rice

Author: Junzhong Liu c, Zuhua He a b d

Issue&Volume: 2024/12/09

Abstract: Nucleotide-binding leucine-rich repeat (NLR) receptors mediate pathogen effector-triggered immunity (ETI) in plants, and a subclass of NLRs are hypothesized to function at the plasma membrane (PM). However, how NLR traffic and PM delivery are regulated during immune responses remains largely unknown. The rice NLR PigmR confers broad-spectrum resistance to the blast fungus Magnaporthe oryzae. Here, we report that a PRA (prenylated Rab acceptor) protein, PIBP4 (PigmR-INTERACTING and BLAST RESISTANCE PROTEIN 4), interacts with both PigmR and the active form of the Rab GTPase, OsRab5a, thereby loads a portion of PigmR on trafficking vesicles that target to PM microdomains. Microdomain-localized PigmR interacts with and activates the small GTPase OsRac1, which triggers reactive oxygen species signaling and hypersensitive response, leading to immune responses against blast infection. Thus, our study discovers a previously unknown mechanism that deploys a PRA-Rab protein delivering hub to ensure ETI, linking the membrane trafficking machinery with NLR function and immune activation in plants.

DOI: 10.1016/j.scib.2024.12.007

Source: https://www.sciencedirect.com/science/article/abs/pii/S2095927324009113