植物干细胞的先天抗病毒免疫

2020年10月9日发表于《科学》杂志上的“WUSCHEL triggers innate antiviral immunity in plant stem cells”揭示了植物干细胞是如何抵御病毒侵染的分子机制。

Building a safe space for stem cells
The meristem, the collection of stem cells that builds plants, is resistant to viral infection. Wu et al. now show that WUSCHEL, a transcription factor that helps to sustain stem cell production in the shoot apical meristem of Arabidopsis, also protects that stem cell domain from viruses. WUSCHEL inhibited viral protein synthesis by repressing methyltransferases that regulate ribosomal RNA processing and ribosome stability.
Abstract
Stem cells in plants constantly supply daughter cells to form new organs and are expected to safeguard the integrity of the cells from biological invasion. Here, we show how stem cells of the Arabidopsis shoot apical meristem and their nascent daughter cells suppress infection by cucumber mosaic virus (CMV). The stem cell regulator WUSCHEL responds to CMV infection and represses virus accumulation in the meristem central and peripheral zones. WUSCHEL inhibits viral protein synthesis by repressing the expression of plant S-adenosyl-L-methionine–dependent methyltransferases, which are involved in ribosomal RNA processing and ribosome stability. Our results reveal a conserved strategy in plants to protect stem cells against viral intrusion and provide a molecular basis for WUSCHEL-mediated broad-spectrum innate antiviral immunity in plants.

植物干细胞的先天抗病毒免疫

解析WUS介导干细胞免疫病毒的分子机制，作者发现WUS蛋白可以直接抑制一类核糖体RNA甲基转移酶基因（S-adenosyl-L-methionine-dependent methyltransferases），影响rRNA的加工和核糖体的稳态，进而可以抑制病毒蛋白质的合成。为了研究WUS介导的干细胞抗病毒免疫是否具有广谱性，该研究还检查了其他三种植物病毒，得到了一致的结论。

该研究揭示了植物茎顶端分生组织存在广谱抗病毒免疫的分子机制。在侵染过程中，病毒必须利用植物细胞内的蛋白质合成系统合成自身的蛋白，以完成自身的复制、组装和侵染过程。而干细胞关键调节基因WUS则通过直接抑制细胞内蛋白质合成的速率，限制了病毒的复制和传播（如图）。为作物抗病毒防治提供了新的思路。