|Redinbaugh, Margaret - Peg|
Submitted to: International Congress on Molecular Plant-Microbe Interactions
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2001
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: The maize inbred Pa405 carries a high level of durable resistance to maize dwarf mosaic potyvirus (MDMV). A dominant gene (Mdm1) on the short arm of chromosome 6 confers this resistance. Earlier studies suggested that MDMV was prevented from entering vascular tissues in Pa405. We tested this hypothesis by comparing the distribution of MDMV in the tissue and cells of Pa405 and a susceptible inbred (Oh28). After vascular puncture inoculation (VPI) of maize kernels with MDMV, the first five leaves of Pa405 developed limited mosaic symptoms and Oh28 seedlings developed systemic mosaic symptoms. After leaf rub-inoculation (LRI), Pa405 showed no symptoms, while Oh28 developed systemic mosaic symptoms. After kernel VPI, MDMV was found in the scutellum, embryo and primary leaves of both inbreds, indicating that MDMV entered and replicated in Pa405 cells. Moreover, the virus was present in all cell types of both lines, including vascular cells. However, different levels and distribution of MDMV were noted in leaves of the two inbreds. Virus was present at high levels in localized areas of Pa405 tissues, but the virus was present in most cells at variable levels in Oh28. After LRI, MDMV was also found in all cell types of both inbreds both the site of inoculation and in leaf tissues proximal to it. While these results were consistent with a limitation to MDMV movement in Pa405, the presence of MDMV in all cell types of the resistant inbred indicated that host resistance was not associated with exclusion of the virus from vascular tissues.