Science Update

Testing Control-pollinated seeds for oxalic oxidase activity (OxO)

This past summer, staff, and colleagues at PSU made a goal to place 1,000 pollination bags on flowering trees at the PSU Arboretum seed orchard. Most of those B3F2 trees have been selected for high blight resistance, but some were selected for other interesting genetic components. Those 1,000 bags yielded 3,704 seeds, created with transgenic pollen from partners at the University of New England and SUNY-ESF.

Over the past few years, ESF and TACF collaborators have averaged 40% transmission of the OxO transgene from controlled pollinations, and our results hit that number right on the nose. On our best day, our team of 3 were able to test 1,031 seed across 12 hours. From several days of testing, we retrieved 1,487 OxO positive nuts, exactly 40% of our harvested numbers.

It was a lot of work and our hands were very tired and covered in paint by the end of the day, but it was worth it. These seeds, now part of TACFs “stacked resistance” program combining resistance from traditional breeding and biotech programs, will be tested for blight resistance this summer in greenhouse inoculation trials at three different locations.

Volunteer Opportunity @ PSU

Thursday, March 3, and Friday, March 4
206 Forest Resources Lab, University Park, PA
Contact Sara Fitzsimmons to volunteer

Description: Volunteers will help staff with testing open-pollinated seeds for oxalic oxidase (OxO) activity.


If transgenic pollen is applied to a non-transgenic tree, that tree is now considered a “regulated organism” (the entire tree), and any “vegetative propagule” (in this case, chestnut seeds) obtained from it must either be “devitalized” (destroyed) or be proven to not be transgenic so that it can be planted outside of permitting. Our goal in early March will be to test as many open-pollinated seeds as possible so that they can be used for further out-planting and research. The tested and OxO negative seeds will be subsequently sent to nurseries for further propagation.