COMPARISON OF WHEAT SPINDLE STREAK MOSAIC VIRUS (WSSMV) AND BARLEY YELLOW MOSAIC VIRUS (BAYMV) - 2 CLOSELY RELATED BYMOVIRUSES

摘要

In order to better understand the evolutionary development that leads to different host ranges, we made a comparison of the closely related barley yellow mosaic bymovirus (BaYMV) and wheat spindle streak mosaic bymovirus (WSSMV). Using different methods both viruses were found to be closely related. Leaves of BaYMV-infected winter barley and WSSMV-infected wheat typically showed similar symptoms. Electron microscopy studies revealed that both viruses lead to formation of 2 types of cytoplasmic inclusions bodies (Cl, 'pinwheel' structures; crystal-like respectively membranous) in infected cells that showed structural differences. This close relationship is also reflected by the high degree of amino acid sequence homology (74% in CP-, 83% in Nlb-, 68% in Nla-region). In spite of the remarkably high similarities both viruses have separate hosts. We demonstrated that, independently of the host range, a reliable distinction between WSSMV and BaYMV is possible using Northern blot hybridisation, reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis. Antisera raised against BaYMV proteins also detected WSSMV proteins in Western blot analyses. Even though corresponding proteins of both viruses were usually similar in size, the BaYMV-Cl antiserum cross-reacted with an additional protein about 8 kDa larger in wheat extracts and the BaYMV 28 kDa antiserum detected a protein of about 30 kDa in wheat extracts.