Transient Overexpression GRF5-VP64-GIF1 enhances the efficiency of regeneration of Chrysanthemum morifolium and Tanacetum cinerariifolium

The Asteraceae family, encompassing economically and aesthetically important genera such as chrysanthemum (Chrysanthemum × morifolium) and pyrethrum (Tanacetum cinerariifolium), holds substantial potential for ornamental, medicinal, and industrial applications. However, challenges in genetic transformation, primarily due to genotype-dependent regeneration barriers, significantly hinder advanced genetic research within this family. To overcome these obstacles, our study introduces a novel regeneration strategy that employing a chimeric transcriptional activation complex combining the potent VP64 transcriptional activator with Arabidopsis GROWTH-REGULATING FACTOR 5 (AtGRF5) and GRF-INTERACTING FACTOR 1 (AtGIF1). This strategy markedly improved shoot induction and regeneration frequencies across various chrysanthemum and pyrethrum genotypes, achieving noTable 5–10-fold increases in these parameters in these parameters in genotypes traditionally challenging to regenerate. Additionally, this approach boosted the transformation efficiency, as demonstrated by a 7-fold increase in chrysanthemum ‘1581’ following co-transformation with genetic vectors. Moreover, this approach enabled the successful transformation of the chrysanthemum genotypes ‘LM28–4’ and pyrethrum ‘W99’, which are relatively challenging to genetic modify. The broad applicability of this technique opens new avenues for the regeneration and genetic modification of a wide range of plant species, offering a fresh perspective on biotechnological interventions in horticulture.