'HoneySweet', a New GE Plum Cultivar - From Concept to Product

Genetic engineering (GE) has been intensively used to improve major agronomic crops but it has not been widely used in woody perennials, species that have the greatest need for this technology due to their protracted breeding cycles. The GE research and development (R&D) pipeline for woody perennials generally ends at proof-of-concept with few products entering the market. The USDA-ARS Appalachian Fruit Research Station fruit breeding program in collaboration with U.S. and European partners developed a GE approach to target resistance to Plum Pox Virus (PPV) the causal agent of Sharka, one of the most destructive diseases of stone fruits (Prunus sp.)  This program developed ‘HoneySweet’, a PPV resistant, GE plum cultivar that has been tested for over 15 years in Europe and in the U.S.   The ‘HoneySweet’ R&D pipeline included elucidation of transgene structure and expression, fruit compositional analyses, environmental risk assessments, tests of the durability of PPV resistance over time and under pressure of multiple Prunus viruses, effects on virus diversity and on non-target insects, and gene flow.  These data moved ‘HoneySweet’ through the R&D pipeline to regulatory submissions.  ‘HoneySweet’ was the first woody perennial to receive full regulatory approval in the U.S.  ‘HoneySweet’ represents a new and novel source of PPV resistance available to growers and a germplasm resource for breeders with which to produce additional PPV resistant cultivars.  The development, regulatory approval, and release of ‘HoneySweet’ plum provides an example of public institution GE R&D that offers practical solutions to challenges affecting agricultural production and food security.