Establishment and characterization of Prosopis laevigata (Humb. & Bonpl. ex Willd) M.C. Johnst. cell suspension culture: A biotechnology approach for mesquite gum production

This study presents a protocol for the establishment of Prosopis laevigata cell suspension culture as a strategy to obtain an in vitro mesquite gum productive cell line. The callus used for this purpose was obtained with hypocotyls from 15-day-old plantlets, placed on Murashige-Skoog medium with two different plant growth regulators (PGRs), 2,4,5-trichlorophenoxy acetic acid (2,4,5-T; 5. 0 μM) and kinetin (KIN; 5. 0 μM). With this PGRs treatment, after four subcultures (30 days each) an exuded gum-like substance was observed on the callus surface. The growth kinetics of the cell suspension culture showed a specific cell growth rate (μ) of 0. 14 d^-1 and doubling time (t_d) of 6. 6 days, respectively. The gum-like substance from callus culture and the broth from cell suspension culture were subjected to chemical analysis and compared with the mesquite gum exuded from wild trees. Both, gum-like substance from callus culture and the broth from cell suspension culture showed the presence of Arabinogalactan-proteins, and their polysaccharide fraction presented the same monosaccharides as those isolated from mesquite gum. In addition, the emulsifying properties of gum-like substance from callus culture and the broth from cell suspension culture were compared to those of mesquite gum and all three samples exhibited similar emulsifying capacity and emulsification stability.