Department of Plant Pathology, University of Florida Gainesville, FL, USA.
Front Microbiol. 2013 Apr 4;4:76. doi: 10.3389/fmicb.2013.00076. eCollection 2013.
Citrus tristeza virus (CTV) causes two citrus diseases that have caused devastating losses in global citrus production. The first disease is quick decline of trees propagated on the sour orange rootstock. The second disease is stem pitting, which severely affects a number of economically important citrus varieties regardless of the rootstock used and results in reduced tree growth and vigor as well as in reduced fruit size and quality. Both diseases continue to invade new areas. While quick decline could be effectively managed by the use of resistant and/or tolerant rootstocks, the only means to protect commercial citrus against endemic stem pitting isolates of CTV has been cross-protection with mild isolates of the virus. In some citrus areas cross-protection has been successful and allowed production of certain citrus cultivars despite the presence of severe stem pitting isolates in those regions. However, many other attempts to find isolates that would provide sustained protection against aggressive isolates of the virus had failed. In general, there has been no understanding why some mild isolates were effective and others failed to protect. We have been working on the mechanism of cross-protection by CTV. Recent considerable progress has significantly advanced our understanding of how cross-protection may work in the citrus/CTV pathosystem. As we demonstrated, only isolates that belong to the same strain of the virus cross protect against each other, while isolates from different strains do not. We believe that the results of our research could now make finding protecting isolates relatively straightforward. This review discusses some of the history of CTV cross-protection along with the recent findings and our "recipe" for selection of protecting isolates.
甜橙衰退病毒（CTV）引起两种柑橘病害，在全球柑橘生产中造成了毁灭性损失。第一种病害是在酸橙砧木上繁殖的树快速衰退。第二种病害是茎陷斑病，无论使用哪种砧木，它都会严重影响许多经济上重要的柑橘品种，导致树木生长和活力减弱，果实变小和质量降低。这两种病害都在继续侵袭新的地区。虽然利用抗性和/或耐性砧木可以有效地管理快速衰退病，但保护商业柑橘免受CTV 地方性茎陷斑病分离物侵害的唯一方法是用病毒的温和分离物进行交叉保护。在一些柑橘产区，交叉保护已取得成功，尽管这些地区存在严重的茎陷斑病分离物，但仍允许生产某些柑橘品种。然而，许多其他试图找到能够对病毒的侵袭性分离物提供持续保护的尝试都失败了。一般来说，人们不理解为什么有些温和的分离物有效，而其他的则不能保护。我们一直在研究 CTV 的交叉保护机制。最近取得的相当大的进展显著提高了我们对交叉保护在柑橘/CTV 病理系统中如何起作用的理解。正如我们所证明的，只有属于同一病毒株的分离物才能相互交叉保护，而来自不同株的分离物则不能。我们相信，我们研究的结果现在可以使寻找保护分离物相对简单。这篇综述讨论了 CTV 交叉保护的一些历史，以及最近的发现和我们选择保护分离物的“配方”。
