Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/1998
Publication Date: N/A
Citation: N/A Interpretive Summary: In all wheat growing regions of the world, the most significant viral pathogen is barley yellow dwarf virus (BYDV). However, there is no natural BYDV resistance in wheat. This study was conducted to determine the effectiveness of BYDV resistance integrated into wheat from a related wheatgrass species. The results obtained demonstrated that this wheatgrass-derived resistance provides immunity to group II strains of BYDV and is moderately effective against subgroup I strains. This study also showed that this resistance operates at the whole plant level and not in single isolated wheat leaf cells. These data suggest that this resistance has the potential for significantly decreasing yield loss due to BYDV infection. This resistance is the only effective BYDV resistance available in wheat. Consequently, the wheat lines used in this study and related wheat germplasm will be used as sources of BYDV resistance by both public and private wheat breeders in the United States and the world.
Technical Abstract: The level of resistance to barley yellow dwarf virus subgroup I and subgroup II strains in wheatgrass (Thinopyrum intermedium) plants is extremely high. A wheat line (P29), in which the 7D chromosome has been substituted with a group 7 chromosome from Thinopyrum intermedium (Th. intermedium), was examined for the level of resistance to two subgroup pI and two subgroup II barley yellow dwarf virus (BYDV) strains. In P29 plants inoculated with the subgroup IPAV strains the level of virus in leaf and stem tissue was reduced 51 percent and 42 percent depending upon the PAV strain when compared with the BYDV susceptible cv Abe. No differences in the level of PAV were observed in roots of P29 and Abe. These results and the absence of detectable virus in inoculated Th. intermedium plants indicate that the complete subgroup I resistance contained in the wheatgrass has not been introgressed into P29. In contrast, P29 was completely resistant throughout the plant to the subgroup II strains, NY-RPV and NY-RMV demonstrating the extreme subgroup II resistance in Th. intermedium was incorporated into P29. Further analysis of this resistance to NY-RPV has shown that NY-RPV can replicate in protoplasts of P29 and Abe suggesting that this resistance is not operating at the single cell level. Molecular marker analysis has confirmed that the Th. intermedium chromosome present in P29 is a different group 7 wheatgrass chromosome than that present in L1, a wheat line reported to have similar BYDV resistance properties.