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

樱桃卷叶病毒是一种在世界范围内传播的线虫传多角体病毒，可感染广泛的木本宿主。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重要流行特征，但种子感染的潜在机制尚未明确。在对桦树和拟南芥幼苗进行CLRV的传播实验后，已经获得了病毒垂直传播的证据，这是由于病毒在胚中的存在而不是由于种皮的污染。胚胎入侵被认为是通过受精前配子的入侵（间接胚胎入侵）发生的。为了研究病毒-植物互作在分生组织入侵和种子传播中的作用，我们将酵母双杂交系统方法应用于CLRV/A模型系统。thaliana.我们调查的目的是确定负责种子传播的宿主和病毒因素，以确认我们的模型系统中的花分生组织的病毒入侵，并将病毒定位在自然宿主的植物组织中。关于CLRV的进一步流行病学研究，我们打算调查可能通过节肢动物媒介传播的桦树林和接骨木种植园在德国和芬兰。传播CLRV通过蚜虫和螨推测，这可能构成一个因素，可能是负责最近广泛的CLRV流行病在北欧桦树林。

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.