Broomrape Can Acquire Viruses from Its Hosts

Abstract

Broomrapes (Phelipanche, formerly Orobanche) are parasitic plants that physically connect with the vascular systems of their hosts through haustorial structures. In this study, we found that Cucumber mosaic virus (CMV), Tomato mosaic virus (ToMV), Potato virus Y (PVY), and Tomato yellow leaf curl virus (TYLCV) translocate from infected host plants to Phelipanche aegyptiaca. In order to examine whether these viruses, and specifically CMV, replicate in the parasite, we tested several replication parameters. We detected accumulation of both plus and minus strands of CMV genomic RNA and CMV-derived siRNAs in the shoots of Phelipanche grown on CMV-infected tobacco and tomato plants. We purified CMV particles from Phelipanche grown on CMV-infected plants. These particles were present in amounts comparable to those found in the hosts' leaves. These data indicate that CMV replicates in Phelipanche tissues. In addition, viable ToMV and PVY were observed, and the plus and minus strand RNAs of ToMV were detected in Phelipanche shoots grown on infected hosts. However, we found only low levels of ToMV coat protein and did not detect any PVY coat protein. We also detected genomic TYLCV DNA in shoots of Phelipanche grown on TYLCV-infected tomato. Thus, for the first time, we demonstrate that broomrape is a host for at least one plant virus CMV, and possibly various other viruses.