To construct the upp-based counterselection system for P. mendocina NK-01 (Fig. 1), a 5-FU resistant strain was constructed initially. Based on homologous recombination, the chromosomal upp gene was deleted
To construct the upp-based counterselection system for P. mendocinaNK-01 (Fig. 1), a 5-FU resistant strain was constructed initially. Based onhomologous recombination, the chromosomal upp gene was deleted