Genetic engineering approach for enhancing abiotic stress tolerance in Sapa lily (Lilium poilanei)

Genetic engineering is one of the best approaches for improving plant resistance to environmental abiotic stress. In this study, genetic engineering was used to enhance the tolerance ability of lily plants under several environmental harsh conditions. The Agrobacterium tumefaciens bacteria with recombinant vectors including the CodA gene controlled by HSP promoter were used for producing transgenic lily plants in vitro. To increase the transformation efficiency of bulb-scale slices, several factors were optimized. The optimal transformation was obtained with 100 µM AS, OD₆₀₀ 0.7 of bacteria concentration, and 3 days of co-cultivation. Moreover, 19.77% of in vitro hygromycin-resistant lines survived after heat stress (39±1°C, 13 days) and formed new bulblets with a coefficient after 2 months in the recovery stage. In addition, among these antibiotic-resistant and heat-tolerant lines, 31.7 and 17% of them could survive in the MS medium with 6 and 9% polyethylene glycol, respectively, while around 11 and 5% of them could survive in the MS medium supplemented with 300 and 400 µM NaCl, respectively. Transgenic lines were also confirmed through Gus gene expression and the presence of HSP and CodA genes. Moreover, the accumulation of glycine betaine in transgenic lines was approximately 1.6 and 4.7 times higher than wild type under normal conditions or heat stress, respectively. This result proves that genetic engineering is a potentially effective strategy to cope with extreme environmental conditions.