Two vacuole-mediated defense strategies in plants
Two vacuole-mediated defense strategies in plants
复制标题
DOI：
10.4161/psb.5.12.13319
复制
发表时间：
2010-01-01
影响因子：
2.9
通讯作者：
Hara-Nishimura, Ikuko
中科院分区：
文献类型：
--
作者：
Hatsugai, Noriyuki;Hara-Nishimura, Ikuko
由于植物缺乏免疫细胞，每个细胞都必须防御入侵的病原体。植物细胞有一个大的中央液泡，它积累了各种水解酶和抗菌化合物，增加了液泡在植物防御中发挥作用的可能性。然而，植物如何利用液泡来防御入侵的病原体却知之甚少。最近，我们描述了两种与程序性细胞死亡(PCD)相关的液泡介导的防御策略。在一种策略中，液泡处理酶(VPE)介导了液泡膜的破坏，导致空泡内容物释放到细胞质中，以响应病毒感染。在另一种策略中，依赖于蛋白酶体的中央空泡与质膜的融合导致空泡抗菌蛋白水解酶和促进细胞死亡的内容物从细胞中排出，以响应细菌感染。有趣的是，这两种策略都依赖于具有caspase样活性的酶：液泡膜崩溃系统需要具有caspase-1样活性的VPE，而膜融合系统需要具有caspase-3样活性的蛋白酶体。因此，植物可能已经进化出一种细胞免疫系统，包括液泡膜崩溃以防止病毒病原体的系统性传播，以及膜融合以抑制细菌病原体的增殖。
As plants lack immune cells, each cell has to defend itself against invading pathogens. Plant cells have a large central vacuole that accumulates a variety of hydrolytic enzymes and antimicrobial compounds, raising the possibility that vacuoles play a role in plant defense. However, how plants use vacuoles to protect against invading pathogens is poorly understood. Recently, we characterized two vacuole-mediated defense strategies associated with programmed cell death (PCD). In one strategy, vacuolar processing enzyme (VPE) mediated the disruption of the vacuolar membrane, resulting in the release of vacuolar contents into the cytoplasm in response to viral infection. In the other strategy, proteasome-dependent fusion of the central vacuole with the plasma membrane caused the discharge of vacuolar antibacterial protease and cell death-promoting contents from the cell in response to bacterial infection. Intriguingly, both strategies relied on enzymes with caspase-like activities: the vacuolar membrane-collapse system required VPE, which has caspase-1-like activity and the membrane-fusion system required a proteasome that has caspase-3-like activity. Thus, plants may have evolved a cellular immune system that involves vacuolar membrane collapse to prevent the systemic spread of viral pathogens and membrane fusion to inhibit the proliferation of bacterial pathogens.