Location: Sunflower Improvement Research
Project Number: 3060-21220-034-031-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Apr 1, 2024
End Date: Mar 31, 2025
Objective:
Develop novel reagent delivery and tissue regeneration techniques to increase the scale and efficiency of sunflower transformation.
Approach:
Recently, improved regeneration methods have used developmental regulatory gene (DR) overexpression to directly reprogram the transfected tissues of recalcitrant crops into modified plantlets. While ideally these techniques would be easily transferable across species, it appears that different species have their own challenges and requisite optimizations. In our treatment of sunflower tissues with DRs, we have observed that while cell division and tissue expansion occur the tissues fail to differentiate. Looking to push forward these DR-based methods in sunflowers, improved shooting rates and lessened developmental dysregulation will be necessary. Despite the current limitations, we expect either the application of untested DRs or more precise expression control with those we have tested that we circumvent the differentiation barrier in sunflower. To define the best shoot inducing DRs, we will ectopically overexpress different DR combinations on unique expression cassettes. By synthesizing DR gene fragments and establishing a base cloning set, we can rapidly build combinatorial DR expression plasmids. With these DR expression plasmids, we will test in our Agrobacterium and cotyledon based delivery platform which DRs can induce cell division, shoot differentiation or both. With these DRs defined we can apply these insights for improving sunflower regeneration and thus enable transformation for cultivar engineering.
