The Use of Phosphomannose-isomerase as a Selectable Marker to Recover Transgenic Cauliflower

We attempted to establish a new selection marker system from cauliflower without antibiotics or herbicide. This new selection marker system was based on the principle that only the transformed plants could convert mannose to fructose. A transformed plant could then use the fructose as carbon source by using pmi gene that can recognize phosphomannose-isomerase that converts mannose-6-phosphate into fructose-6-phosphate. Agrobacterium tumefaciens LBA4404 contained pNWB-HSP101 vector linked with HSP101. Five days after germination, the heat tolerant gene was inoculated into the cauliflower's hypocotyl. After culturing, selection was performed in MS medium that contained 2 mgㆍL-¹ BAP, 2 mgㆍL-¹ NAA, 0.4% (w/v) mannose and 2.0% (w/v) sucrose. PCR, Southern blot and Northern blot analyses were performed to determine whether HSP101 gene was inserted in the transformed plant. After acclimation, T₁ seeds were successfully collected from the transformed plants in the greenhouse. This is the first report for successful transformation of cauliflower plant using the mannose selection system. Moreover, the stable selection system established in this study could be applied an alternative reducing antibiotics for human health and environmental safety during the genetic transformation of higher plants.