Cuscuta species (dodders) are holoparasites that totally rely on host plants to survive. Although various mobile proteins have been identified to travel within a plant, whether and to what extent protein transfer between Cuscuta and host plants remain unclear. We found that hundreds to more than 1500 proteins were transferred between Cuscuta and the host plants Arabidopsis and soybean, and hundreds of inter-plant mobile proteins were even detected in the seeds of Cuscuta and the host soybean. Different hosts bridge-connected by dodder were also found to exchange hundreds of proteins. Quantitatively, the mobile proteins represent a few to more than 10% of the proteomes of foreign plants. Using Arabidopsis plants expressing different reporter proteins, we further showed that these reporter proteins could travel between plants and, importantly, retained their activity in the foreign plants. Comparative analysis between the inter-plant mobile proteins and mRNAs indicated that the majority of mobile proteins were not de novo synthesized from the translocated mRNAs, but bona fide mobile proteins. We propose that large-scale inter-plant protein translocation may play an important role in the interactions between host plants and dodder and even among the dodder bridge-connected hosts.

菟丝子属（菟丝子）是完全依赖寄主植物生存的全寄生虫。尽管已发现多种可移动蛋白在植物内移动，但菟丝子和宿主植物之间是否以及在何种程度上进行蛋白转移仍不清楚。我们发现数百至1500多个蛋白质在菟丝子与寄主植物拟南芥和大豆之间转移，甚至在菟丝子和寄主大豆的种子中检测到数百种植物间移动蛋白质。还发现通过菟丝子桥接的不同宿主可以交换数百种蛋白质。从数量上来说，移动蛋白占外来植物蛋白质组的百分之几到百分之十以上。使用表达不同报告蛋白的拟南芥植物，我们进一步表明这些报告蛋白可以在植物之间传播，并且重要的是，在外来植物中保留其活性。植物间移动蛋白和mRNA的比较分析表明，大多数移动蛋白不是由易位的mRNA从头合成的，而是真正的移动蛋白。我们认为，大规模植物间蛋白质易位可能在寄主植物与菟丝子之间甚至菟丝桥连接寄主之间的相互作用中发挥重要作用。