GenBank accession numbers.

<div> Parasitism has evolved independently in various plant families, with <i>Cuscuta campestris</i> (field dodder) being an economically significant example. Despite advances in genomics and transcriptomics, functional studies in <i>C</i>. <i>campestris</i> are limited by the lack of an efficient genetic transformation system. This study introduces a highly effective <i>Rhizobium rhizogenes</i>-mediated transformation system for <i>C</i>. <i>campestris</i> using a pBIN plasmid harboring a Yellow Fluorescence Protein reporter gene. We optimized transformation and regeneration by assessing explant type, media composition, and plant growth regulators. Notably, host plant contact was essential for transgenic shoot regeneration. Over 70% transformation efficiency was achieved using cuttings co-incubated with modified Murashige and Skoog medium and 5 mg/L Benzylaminopurine, followed by transfer to tomato hosts. Additionally, we developed a complete <i>in-vivo</i> protocol over 30% regeneration efficiency. Transgenic shoots were confirmed for <i>rol</i> gene expression and haustoria formation, advancing functional studies in <i>C</i>. <i>campestris</i>. </div>