RNA interference, or RNA silencing, is an important defence mechanism against viroid infection in plants. Plants encode multiple DICER‐LIKE (DCL) proteins that are key components of the RNA silencing pathway. However, the roles of different DCLs in defence responses against viroid infection remain unclear. Here, we determined the function of tomato DCL2b (SlDCL2b) in defence responses against potato spindle tuber viroid (PSTVd) infection using SlDCL2b loss‐of‐function tomato mutant plants. Compared with wild‐type plants, mutant plants were more susceptible to PSTVd infection, developing more severe symptoms earlier and accumulating higher levels of PSTVd RNAs. Moreover, we verified the feedback mechanism for the regulation of SlDCL2b expression by miR6026. Functional blocking of tomato miR6026, by expressing its target mimics, can enhance resistance to PSTVd infection in tomato plants. These findings deepen the current understanding of RNAi‐based resistance against viroid infection and provide a potentially new strategy for viroid control.

中文翻译：

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SlDCL2b 的敲除减弱了番茄对马铃薯纺锤体类病毒感染的抵抗力

RNA干扰或RNA沉默是植物抵御类病毒感染的重要防御机制。植物编码多种 DICER 样 (DCL) 蛋白，它们是 RNA 沉默途径的关键组成部分。然而，不同 DCL 在类病毒感染防御反应中的作用仍不清楚。在这里，我们确定了番茄 DCL2b (SlDCL2b) 在马铃薯纺锤块茎类病毒 (PSTVd) 感染防御反应中的功能sDCL2b丧失功能的番茄突变体植物。与野生型植物相比，突变植物更容易受到 PSTVd 感染，更早出现更严重的症状，并积累更高水平的 PSTVd RNA。此外，我们还验证了监管的反馈机制。sDCL2bmiR6026 的表达。通过表达其靶标模拟物，对番茄 miR6026 进行功能阻断，可以增强番茄植株对 PSTVd 感染的抵抗力。这些发现加深了目前对基于 RNAi 的类病毒感染抵抗力的理解，并为类病毒控制提供了一种潜在的新策略。