抗病小体:植物免疫机器

Resistosomes:plant immune machines

在与各种病原微生物长期互作的过程中,植物演化出时空上紧密关联的多层防御系统来对抗各种病虫害的威胁.其中关键的一层是由细胞内NLR免疫受体(Nucleotide binding domain and leucine-rich repeat-containing receptors,NLRs)通过识别病原菌分泌到植物细胞内的效应蛋白(Effectors)进而激活的特异性免疫反应(Effector-triggered immunity,ETI).这一层免疫具有特异性强、反应快、反应强度高等特点,并能够引发植物的系统获得性免疫反应,因此这种形式的免疫受到了植物抗病及育种领域的广泛关注.近几年,在我们实验室及国际国内同行的共同努力下,我们对植物不同类型NLRs的静息状态的维持、特异性识别效应蛋白及NLRs由静息态转变为激活状态的分子机制都有了深入的认识.据此,我们创新性的提出了NLRs激活状态的结构—抗病小体(Resistosomes)这一概念,并通过生化实验和植物体内实验揭示了植物不同种类抗病小体具有阳离子通道或者NAD+水解酶活性,我们也提出了钙离子作为共同的下游信号,在不同类型的抗病小体介导的ETI免疫反应中行使作用.抗病小体的发现为深入研究NLRs如何介导植物抗病及超敏反应奠定了坚实基础,这一概念的提出也迅速得到了植物抗病领域同行的高度认同.此外,抗病小体的发现也为培育广谱抗病性作物提供了理论依据.

In the process of the long-term interaction with various pathogenic microorganisms,plants have evolved into a multi-layered defense system.The ETI(effector-triggered immunity)is the specific immune response activated by the nucleotide-binding domain and leucine-rich repeat-containing receptors(NLRs),which recognize effector proteins secreted into plant cells by pathogenic bacteria.Recent studies have demonstrated that the recognition of effector proteins induces the formation of large protein complexes to mediate NLR immune signaling.Based on these findings,we have innovatively proposed the concept of“resistosomes”for the large protein complexes involved in NLR activation.We revealed that different NLR resistosomes exhibit cation channels or NAD+hydrolase activities.Additionally,we propose calcium ions as a common downstream signal for resistosome-mediated immune responses.The discovery of resistosomes has laid a solid foundation for in-depth research into how NLRs mediate plant disease resistance and hypersensitivity reactions.Furthermore,the identification of resistosomes provides a theoretical basis for breeding broad-spectrum disease-resistant crops.