TY - JOUR
T1 - A transgenic tropical maize line generated by the direct transformation of the embryo-scutellum by A. tumefaciens
AU - Valdez-Ortiz, Angel
AU - Medina-Godoy, Sergio
AU - Valverde, M. Elena
AU - Paredes-López, Octavio
N1 - Funding Information:
Acknowledgements The authors would like to thank H.G. Mena-Violante, from CINVESTAV-IPN, for discussion and reviewing this paper, Dr. O. Martinez-De la Vega for valuable help in statical analyses. The partial financial support from CONACYT-Mexico is acknowledged as well.
PY - 2007/12
Y1 - 2007/12
N2 - An efficient Agrobacterium-mediated transformation system, from which transgenic tropical maize plants were directly generated without previous crosses with laboratory or temperate lines, was established. Experimental evaluations were focused on two main issues: (i) establishment of appropriate tissue culture conditions, which induced somatic embryogenesis from the scutellum-cells, and (ii) the delivery of T-DNA toward these cells. High rates of embryogenic-calli, mainly generated from the embryo-scutellum, were obtained when 15 mg l-1 AgNO3 were included into the N6-based induction medium; rates up to 19 plants per gram were regenerated from these induced calli. Regarding the Agrobacterium strains evaluated for their transformation capability on the tropical maize line LPC13 used here, best results were obtained from the EHA105 cells when applied at OD550 nm = 0.5-1.0. Physical microwounds before the Agro-infection proved to be an excellent way to promoting both the T-DNA transferring toward the embryo-scutellum and the increasing of rates of transient GUS expression. The highest frequencies of transient GUS expression corresponding to the scutellum-cells as well as the regeneration of whole transgenic plants emerged from them, were obtained using immature embryos wounded by bombarding at 80 lb/in2 followed for vacuum infiltration before and during the Agro-infection, respectively, or using embryos wounded by 5 s-sonication (without vacuum infiltration) before the Agro-infection. Transformation frequencies up to 5.41% and 6.82% were obtained from the Agro-infected embryos wounded by particle-bombardment and sonication, respectively. Analyses of the progenies confirmed the sexual transmission of the introduced genes and their stable expression.
AB - An efficient Agrobacterium-mediated transformation system, from which transgenic tropical maize plants were directly generated without previous crosses with laboratory or temperate lines, was established. Experimental evaluations were focused on two main issues: (i) establishment of appropriate tissue culture conditions, which induced somatic embryogenesis from the scutellum-cells, and (ii) the delivery of T-DNA toward these cells. High rates of embryogenic-calli, mainly generated from the embryo-scutellum, were obtained when 15 mg l-1 AgNO3 were included into the N6-based induction medium; rates up to 19 plants per gram were regenerated from these induced calli. Regarding the Agrobacterium strains evaluated for their transformation capability on the tropical maize line LPC13 used here, best results were obtained from the EHA105 cells when applied at OD550 nm = 0.5-1.0. Physical microwounds before the Agro-infection proved to be an excellent way to promoting both the T-DNA transferring toward the embryo-scutellum and the increasing of rates of transient GUS expression. The highest frequencies of transient GUS expression corresponding to the scutellum-cells as well as the regeneration of whole transgenic plants emerged from them, were obtained using immature embryos wounded by bombarding at 80 lb/in2 followed for vacuum infiltration before and during the Agro-infection, respectively, or using embryos wounded by 5 s-sonication (without vacuum infiltration) before the Agro-infection. Transformation frequencies up to 5.41% and 6.82% were obtained from the Agro-infected embryos wounded by particle-bombardment and sonication, respectively. Analyses of the progenies confirmed the sexual transmission of the introduced genes and their stable expression.
KW - Agro-infection
KW - Embryo-scutellum
KW - Particle-bombardment
KW - Silver nitrate
KW - Somatic-embryogenesis
KW - Sonication
KW - Wounds
UR - http://www.scopus.com/inward/record.url?scp=35548958231&partnerID=8YFLogxK
U2 - 10.1007/s11240-007-9286-4
DO - 10.1007/s11240-007-9286-4
M3 - Artículo
SN - 0167-6857
VL - 91
SP - 201
EP - 214
JO - Plant Cell, Tissue and Organ Culture
JF - Plant Cell, Tissue and Organ Culture
IS - 3
ER -