Establish methods to improve the efficiency of tissue-free genetic transformation of medicinal plants through mechanical damage

Medicinal plants are widely used in various fields, such as medicine, fragrance production, cosmetics and food. However, only a small number of medicinal plants can be genetically modified, making it difficult to improve these plants through genetic engineering. A tissue culture-free method was established to transform three medicinal plants: <italic>Cynanchi stauntonii</italic>, <italic>Artemisia argyi,</italic> and <italic>Chrysanthemum morifolium.</italic> In this method, mechanical damage and <italic>Agrobacterium rhizogenes</italic> species were found to significantly enhance infection efficiency. The results showed that <italic>A. rhizogenes</italic> strain A4 achieved the highest induction rates in <italic>C. stauntonii</italic>, while strain MSU440 demonstrated superior transformation efficiency in both <italic>A. argyi</italic> and <italic>C. morifolium</italic>. Additionally, scraping off the basal epidermis with a blade to create mechanical damage significantly enhanced infection efficiency in the three medicinal plants. Through <italic>A. rhizogenes</italic> strain selection and infection method optimization, <italic>C. stauntonii</italic>, <italic>A. argyi,</italic> and <italic>C. morifolium</italic> achieved the highest transformation efficiencies of 51.7%, 9.3%, and 16.7%, respectively. This gene transformation technology overcomes the technical problems of low efficiency, long experiment period and high cost, and provides a valuable tool for genetic research and precise breeding of medicinal plants.