Modes of transmission of the Cherry leaf roll virus: genetic basis of seed transmissibility and investigation of possible arthropod vectors

樱桃叶卷病毒是一种在世界范围内传播的病毒，可以感染多种木质宿主。据报道，该病毒在自然界中主要通过种子垂直传播，但也通过花粉水平传播。虽然通过种子传播是许多植物病毒的一个重要流行特征，但种子感染的潜在机制尚不明确。在桦树和拟南芥幼苗上进行CLRV传播实验后，有证据表明，病毒的垂直传播是由于病毒在胚胎中存在，而不是由于种皮受到污染。胚胎入侵被认为是通过受精前的配子入侵发生的（间接胚胎入侵）。为了研究病毒与植物在分生组织入侵和种子传播过程中的相互作用，我们打算在模型系统CLRV/A上应用酵母双杂交系统方法。芥。我们研究的目的是确定负责种子传播的宿主和病毒因素，在我们的模型系统中确认病毒对花分生组织的入侵，并在自然宿主的植物组织中定位病毒。关于CLRV的进一步流行病学研究，我们打算调查在德国和芬兰的白桦林和接骨木人工林中通过节肢动物媒介传播的可能性。推测CLRV通过蚜虫和螨虫传播；这可能是造成最近在北欧桦树林中广泛流行CLRV的一个潜在因素。

Cherry leaf roll virus is a worldwide spread Nepovirus that infects a wide range of woody hosts. The virus is reported to spread in nature mainly vertically by seed, but also horizontally by pollen. Although transmission through seed is a critical epidemic feature of many plant viruses, the underlying mechanisms of seed infection are not specified. After transmission experiments of CLRV on birch and Arabidopsis thaliana seedlings, evidence has been obtained that the vertical spread of the virus is achieved due to the presence of the virus in the embryo rather than due to contamination of the seed coat. The embryo invasion is believed to occur through invasion of the gametes before fertilization (indirect embryo invasion). To investigate virus-plant interactions involved in meristem invasion and seed transmission, we intent to apply the yeast two-hybrid system method on the model system CLRV/A. thaliana. The aim of our investigation is to determine host and viral factors responsible for the seed transmission, to confirm the virus invasion of the floral meristems in our model system and to localize the virus in plant tissues of natural hosts. In regard to further epidemiological studies on CLRV, we intent to investigate possible transmission through arthropod vectors on birch forests and elderberry plantations in Germany and Finland. Transmission of CLRV through aphids and mites is speculated; this may constitute one factor potentially responsible for the recent broad CLRV epidemics in north European birch forests.