Regeneration, genetic transformation, and gene editing in Vaccinium species: current progress and future directions

Vaccinium is one of the most economically significant genera in the Ericaceae family, with breeding efforts substantially improving yield, fruit quality, and adaptation, contributing to the widespread consumption of this berry-bearing clade. Crops within this genus are valued for their high nutritional content, including antioxidants, dietary fiber, and vitamins, as well as their culinary versatility. Health benefits, such as anti-inflammatory activity, combined with advances in breeding and cultivation that enhance flavor and yield, have further boosted consumer demand. However, the application of traditional breeding methods in Vaccinium remains challenging, mostly due to their long juvenile period, polyploidy, and the complex genomes of both cultivated and wild plants. To overcome these constraints, new breeding techniques (NBTs), such as gene editing, offer tremendous potential for developing improved varieties with traits that are difficult to achieve through traditional methods. Over the past 30 years, significant advancements in Vaccinium biotechnology have been made, particularly in the field of transgenesis. These advancements, including the ability to introduce foreign genes and edit genomes, hold great promise for overcoming the challenges posed by traditional breeding techniques. Despite these developments, the implementation of NBTs in Vaccinium remains at an earlier stage compared with other horticultural crops, primarily due to: (i) recalcitrancy to stable genetic transformation and (ii) low editing efficiencies. In this review, we provide a detailed overview of advancements in regeneration and genetic transformation in Vaccinium species, along with a perspective on the major constraints and future strategies to improve Vaccinium through biotechnological methods.