White pine blister rust (WPBR) caused by the fungus Cronartium ribicola is a devastating introduced disease of five-needled pines (Section Strobus) and Ribes species in North America. For almost a century, scientists have attempted to identify and employ resistance to this disease, especially indigenous Pinus species. Although progress has been made, much work remains to be done, especially with Eastern white pine (Pinus strobus).

The impact of WPBR in Minnesota has hampered attempts to replant P. strobus in many high-hazard sites in the northeastern and north-central portions of the state. This is compounded by competition, browsing by deer and white pine weevil (Pissodes strobi). The development of resistant P. strobus seedlings will make planting P. strobus in Minnesota (and other areas of the Lake States, Northeast and Canada) more successful and will significantly improve current efforts to re-establish white pine throughout its original native range.

Our lab is focused on three main areas of white pine blister rust research:
1. Screening Pinus strobus seed sources for resistance to WPBR
2. Identifying resistance mechanisms/traits in resistant phenotypes
3. Ribes screening for development and release of resistant currants

In conjunction with the Minnesota Tree Improvement Cooperative and Dr. Andrew David (North Central Research and Outreach Center, University of Minnesota, Grand Rapids, MN) we are screening Eastern white pine seed sources (primarily from Minnesota) for resistance to WPBR. Using modified techniques developed by Dr. Paul Zambino (USDA Forest Service, Moscow, Idaho), we are screening 3 month-old seedlings for resistance. Several seed sources have been consistently resistant after artificial inoculations and show promise for development of white pine blister-rust resistant P. strobus.

The seed sources identified as resistant by screening are also being used to identify resistance mechanisms/traits in needles and stems that may be used for future selection or breeding strategies. Using histology, scanning electron microscopy and biochemical analyses we are investigating potential mechanisms/traits that may contribute to resistance to white pine blister rust. Research findings indicate that multiple mechanisms may be present in resistant phenotypes.

Publications:

Burnes, T. A., R. A. Blanchette, J. A. Smith and J. J. Luby. 2008. Black currant clonal identity and white pine blister rust resistance. HortScience 43:200-202.( reprint )

Smith, J.A., Blanchette, R.A., Jacobs, J.J., Higgins, L., Witthun, B. A., Gillman, J. H. and A. J. David. 2006. Proteomic comparison of needles from blister rust-resistant and susceptible Pinus strobus seedlings reveals up-regulation of putative disease resistance proteins. Molecular Plant-Microbe Interactions 19: 150-160. (reprint)

Smith, J.A., Blanchette, R.A., Burnes, T.A., Gillman, J.H. and A. J. David. 2006. Epicuticular wax and white pine blister rust resistance in selections of Pinus strobus L. Phytopathology 96: 171-177. (reprint)

Jurgens, J.A., R.A. Blanchette, P.J. Zambino, and A. David. 2003. Histology of white pine blister rust in needles of resistant and susceptible eastern white pine. Plant Disease 87(9): 1026-1030. (reprint)

Smith, J. A. T. A. Burnes, J. A. Jurgens, A. J. David and R. A. Blanchette. 2003. Potential resistance mechanisms in Pinus strobus to Cronartium ribicola. In: Proceedings of the Second IUFRO Rusts of Forest Trees Working Party Conference, 19- 23 Aug., 2002, Xu, M.-Q., Walla, J.A., and Zhao, W.-X. (eds.) Yangling, China Forest Research 16 (Suppl).(reprint)

White pine being attacked by white pine blister rust

Canker caused by white pine blister rust on branch of eastern white pine. The disease will progressively move down the branch into the main stem killing the tree

Seedlings of eastern white pine families in the greenhouse being used for inoculation studies to select resistant white pine to white pine blister rust