A viral counter defence protein as a probe for cross-talk or functional overlap between host defence pathways.

黄瓜花叶病毒（Cucumber mosaic virus，CMV）是危害作物和野生植物最严重的病毒之一，是英国和世界范围内两种重要的温室园艺作物病毒之一。CMV成功的一个重要因素是最近发现的一种称为2b蛋白的因子。这种病毒蛋白执行几项任务，但最重要的是破坏抗病性。我们知道2b蛋白可以抑制两种类型的抗性机制的作用。其中之一被称为系统获得性抗性，其中一种致病微生物的攻击可能会刺激对非常广泛的各种微生物（病毒，真菌，细菌）的更高程度的抗性。被2b蛋白质击败的另一种抗性机制是基于RNA干扰，这是一种将病毒遗传物质识别为外来物质并分解的现象。我们将确定2b蛋白如何影响两种明显非常不同的防御系统，以及在破坏系统获得性抗病毒感染的过程中，2b是否也有可能增加植物对其他致病微生物的易感性。

Cucumber mosaic virus (CMV) is remarkable in that it attacks more crop and wild plant species than any other and it is one of the two most important viruses of field-grown and glasshouse horticultural crops in the UK and worldwide. An essential contributor to the success of CMV is a recently discovered factor called the 2b protein. This viral protein carries out several tasks but its most important is subverting disease resistance. We know that the 2b protein can inhibit the action of two types of resistance mechanism. One of these is called systemic acquired resistance, in which an attack by one disease-causing organism may stimulate a higher degree of resistance to a very broad range of diverse micro-organisms (viruses, fungi, bacteria). The other resistance mechanism defeated by the 2b protein is based on RNA interference, a phenomenon in which viral genetic material is recognised as foreign and broken down. We will determine how the 2b protein affects two apparently very different defence systems and if, in the process of disrupting systemic acquired resistance against virus infection, the 2b also has the potential to increase the susceptibility of plants to other disease causing micro-organisms.