Establishment of genetic transformation system in Lilium pumilum and functional analysis of LpNAC6 on abiotic stress

Abstract

Lilium pumilum is widely distributed in northeast Asia. It exhibits strong resistance and possesses high ornamental value. However, it currently lacks an efficient and stable transformation system. Therefore, we aimed to establish an effective genetic transformation system using the Agrobacterium-mediated method for L. pumilum, enabling gene transfer into the plant for gene function research and genetic engineering breeding. Our genetic transformation system achieved a transformation efficiency of 7.25 % under specific conditions: a kanamycin (Kana) concentration of 120 mg/L, 3 days of pre-cultivation, an A. tumefaciens concentration of 0.7 OD₆₀₀, an acetosyringone (AS) concentration of 20 mg/L, and a 15-minute infection period. We investigated the function of the LpNAC6 from L. pumilum by observing phenotypic and physiological changes under stresses induced by salt, alkali, and drought. Furthermore, overexpression of LpNAC6 resulted in enhanced stress tolerance as evidenced by increased levels of SOD, POD, CAT enzymes, improved photosynthetic indices, and elevated chlorophyll contents; as well as reduced levels of MDA and reactive oxygen species (ROS). These findings demonstrate that we have successfully established a transgenic transformation method for L. pumilum while also providing essential information for cultivating stress-tolerant Lilium species and advancing our understanding of the functions of LpNAC6 in plants.