This study is being approached in three different ways. On one approach, i.e. pathogenesis-related proteins, resistance (Rr) and susceptible (rr) sugar pine (Pinus lambertiana) seedlings were inoculated with white pine blister rust (WPBR) fungus and foliar protein patterns were analyzed by 2-dimensional gel electrophoresis in conjunction with densitometry and computer-assisted gel image analysis. In resistant seedlings, both enhancement and suppression of the biosynthesis of proteins were observed. By contrast, only suppression in the biosynthesis of proteins was observed in susceptible seedlings. Two acidic proteins, 36.7-KDa and 28.1-KDa, were detected in large amounts. The 36.7-KDa protein was suppressed in susceptible seedlings at day 3 while the 28.1-KDa protein was enhanced in resistant seedlings at day 9. In another approach, bark proteins of western white pine (Pinus monticola) trees displaying slow canker growth a form of WPBR were analyzed. A 10.5-KdA protein unique to this resistance type was identified and partially characterized. In the third approach, a series of monoclonal antibodies (Mabs) to WPBR was generated. Although most Mabs were shown to be cross-reactive to western white pine proteins, two Mabs were specific to WPBR. These two Mabs will be used to identify immuncytochemically the pathogen in resistant and susceptible trees during initial infection. In addition, a "cold" protein was shown to be differentially expressed in resistant and susceptible white pine trees, indicating its potential use as a marker for resistance.
Key words: protein marker, resistance, antibody, electrophoresis.
Correspondence: Abul K.M. Ekramoddoullah, Canadian Forest Service, Pacific and Yukon Region, Victoria, British Columbia, Canada