Indirect Somatic Embryogenesis and Cryopreservation of Agave tequilana Weber Cultivar 'Chato'

Agave tequilana Weber cultivar 'Chato' represents an important genetic supply of wild severely in decline populations of 'Chato' for breeding and transformation programs. In this work, the indirect somatic embryogenesis and cryopreservation of Somatic Embryos (SEs) were investigated using the 'Chato' cultivar as a study case. Methods: Embryogenic calli were induced by the cultivation of 1 cm of young leaves from in vitro plants on MS semisolid medium supplemented with 24.84, 33.13, 41.41, 49.69, and 57.98 mu M 4-amino-3,5,6-trichloro-2- pyridinecarboxylic acid (picloram) in combination with 2.21, 3.32, and 4.43 mu M 6-benzylaminopurine (BAP). The origin and structure of formed SEs were verified by histological analysis. Cryopreservation studies of SEs were performed following the V-cryoplate technique and using for dehydration two vitrification solutions (PVS2 and PVS3). Results: The highest average (52.43 +/- 5.74) of produced SEs and the Embryo Forming Capacity (estimated index 52.43) were obtained using 49.69 mu M picloram and 3.32 mu M BAP in the culture medium. The highest post-cryopreservation regrowth (83%) and plant conversion rate (around 70%) were achieved with PVS2 at 0 degrees C for 15 min. Conclusion: Our work provides new advances about somatic embryogenesis in Agave and reports the first results on cryopreservation of SEs of this species.