Cross-protection was first described a century ago. In practical terms, cross-protection consists of the pre-inoculation of plants with mild or attenuated viral isolates that protect the plants from subsequent infections with aggressive isolates. Experimentally, cross-protection has been shown to apply to numerous virus and viroid species infecting numerous plant hosts, but the number of cases in which it has been successfully used for the control of the damage caused by viruses in crops is rather limited. Significant examples include citrus tristeza virus and zucchini yellow mosaic virus, and more recently, pepino mosaic virus (PepMV). PepMV is a pandemic virus affecting tomato crops worldwide. During the first decade of the current century, a number of mild PepMV isolates useful in cross-protection were identified and characterized. Soon after, cross-protection programs against PepMV were implemented in the Netherlands, Belgium, Morocco, and Spain. These programs were easily adopted by farmers, as no other efficient control methods were available and the losses caused by PepMV were unbearable for tomato producers. PepMV cross-protection has been working exceedingly well during this time, although the potential interaction of the PepMV mild isolates with the recently emerging tomato brown rugose fruit virus (ToBRFV) may be threatening its viability. In this review, we describe our experience in deploying cross-protection against PepMV in Spain. In our view, this is an underexploited technology that holds promise, but when it is used and how it is used requires careful thinking and preparation, as not all situations are as favourable for the use of cross-protection as the PepMV pandemic has been.

中文翻译：

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针对凤梨花叶病毒的交叉保护，十多年的有效疾病控制

交叉保护最早是在一个世纪前被描述的。实际上，交叉保护包括用温和或减毒的病毒分离株预先接种植物，以保护植物免受后续侵袭性分离株的感染。实验表明，交叉保护适用于感染多种植物宿主的多种病毒和类病毒物种，但成功用于控制病毒对作物造成的损害的案例数量相当有限。重要的例子包括柑橘 tristeza 病毒和西葫芦黄花叶病毒，以及最近的菠菜花叶病毒 (PepMV)。 PepMV 是一种影响全世界番茄作物的大流行病毒。在本世纪的第一个十年中，鉴定并鉴定了许多可用于交叉保护的温和 PepMV 分离株。不久之后，荷兰、比利时、摩洛哥和西班牙实施了针对 PepMV 的交叉保护计划。这些计划很容易被农民采用，因为没有其他有效的控制方法，而且 PepMV 造成的损失对于番茄生产者来说是难以承受的。尽管 PepMV 轻度分离株与最近出现的番茄棕色皱纹果实病毒 (ToBRFV) 的潜在相互作用可能会威胁其生存能力，但 PepMV 交叉保护在此期间一直发挥着非常良好的作用。在这篇综述中，我们描述了我们在西班牙部署针对 PepMV 的交叉保护的经验。我们认为，这是一项尚未充分利用的技术，前景广阔，但何时使用以及如何使用需要仔细思考和准备，因为并非所有情况都像 PepMV 大流行那样有利于使用交叉保护。