Over-Expression of FT1 in Plum (Prunus domestica) Results in Phenotypes Compatible with Spaceflight: A Potential New Candidate Crop for Bioregenerative Life Support Systems

ABSTRACT Tree fruits (e.g., apples, plums, cherries) are appealing constituents of a crew menu for long-duration exploration missions (i.e., Mars), both in terms of their nutritive and menu diversity contributions. Although appealing, tree fruit species have long been precluded as candidate crops for use in plant-based bioregenerative life support system designs based on their large crown architecture, prolonged juvenile phase, and phenological constraints. Recent advances by researchers at the United States Department of Agriculture (USDA) have led to the development of plum (Prunus domestica) trees ectopically over-expressing the Flowering Locus T-1 (FT1) gene from Populus trichocarpa (poplar). The transformed plants exhibit atypical phenotypes that seemingly eliminate the aforementioned obstacles to spaceflight. Here we demonstrate the FT1 expression system (FasTrack) and the resultant dwarf growth habits, early flowering, and continuous fruit production. The potential contribution of P. domestica as a countermeasure to microgravity-induced bone loss is also discussed.