Stable genetic transformation of lily scales without tissue culture

Lilium brownii is a perennial monocot with significant edible, medicinal, and ornamental value, but its genetic transformation system requires sterile tissue culturing to induce callus formation. However, the existing genetic transformation system for this plant is underdeveloped, resulting in limited research on the genetic improvement of lily and the functional annotation of its genes. Using L. brownii scales, this study established a tissue culture-free genetic transformation system involving Agrobacterium tumefaciens . Additionally, the effects of different A. tumefaciens strains, infection conditions and durations, and the addition of paclobutrazol (PBZ) on infection and callus induction efficiency were systematically investigated. The addition of PBZ increased the scale induction rate, thereby promoting differentiation and survival. Moreover, it increased the bulblet rooting rate and enhanced root growth. According to the study data, the optimal infection system for lily scales comprised the following: A. tumefaciens strain EHA105 (resuspension concentration of OD600 = 1.0) supplemented with PBZ for a shaking culture for 30 min. This system successfully integrated a target gene into the lily genome with a transformation rate of 11.76%. This study optimized key parameters of a tissue culture-free genetic transformation system for lily scales, providing a reference for establishing efficient and stable genetic transformation protocols, with implications for gene editing and molecular breeding of lilies.