Efficient Development of Transgenic Cabbage with Jasmonic Acid Carboxyl Methyltransferase (JMT) Gene Based on PMI / Mannose Selection System

This study aimed to establish a positive selection system for the genetic transformation of cauliflower using the phosphomannose isomerase (PMI) gene. PMI catalyzes the reversible interconversion of mannose 6-phosphate and fructose 6-phosphate. Thus, only plant cells transformed with the PMI gene can survive on synthetic medium containing mannose as a carbon source. Cotyledon explants from 6-day-old seedlings were infected with Agrobacterium tumefaciens strain LBA4404 harboring binary vector pNWB-JMT containing the jasmonic acid carboxyl methyltransferase (JMT) gene with full codon modification. After co-cultivation with Agrobacterium, positive selection was conducted on MS medium supplemented with 2 mg/L of BAP, 1 mg/L of NAA, 0.6% (w/v) mannose, and 2% (w/v) sucrose. Over 40 putative transgenic plants were obtained in the repetitive transformation experiments. The overall transformation efficiency was 1.2% in the mannose-based selection. Polymerase chain reaction along with Southern and Northern blotting analyses were used to confirm and characterize the transgenic plants containing the integrated JMT gene. After soil acclimatization, transgenic plants were successfully grown to maturity in a greenhouse. T1 seeds were successfully collected from these transgenic plants. This is the first successful report of cabbage transformation using a mannose-based selection system. Therefore, the positive selection system established in this study could be applied as an alternative tool for the rapid selection of elite lines for the purposes of breeding and reduction of antibiotic use in order to improve human health and environmental safety