PLANT PHYSIOLOGY , Vol 110, Issue 4 1097-1107, Copyright © 1996 by American Society of Plant Biologists
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GENE REGULATION AND MOLECULAR GENETICS |
The Competence of Maize Shoot Meristems for Integrative Transformation and Inherited Expression of Transgenes
H. Zhong, B. Sun, D. Warkentin, S. Zhang, R. Wu, T. Wu and M. B. Sticklen
202 Pesticide Research Center, Department of Crop and Soil Sciences, Michigan State University, East Lansing, Michigan 48824-1311 (H.Z., B.S., D.W., S.Z., M.B.S.)
We have developed a novel and reproducible system for recovery of fertile
transgenic maize (Zea mays L.) plants. The transformation was performed
using microprojectile bombardment of cultured shoot apices of maize with a
plasmid carrying two linked genes, the Streptomyces hygroscopicus
phosphinothricin acetyltransferase gene (bar) and the potato proteinase
inhibitor II gene, either alone or in combination with another plasmid
containing the 5[prime] region of the rice actin 1 gene fused to the
Escherichia coli [beta]-glucuronidase gene (gus). Bombarded shoot apices
were subsequently multiplied and selected under 3 to 5 mg/L glufosinate
ammonium. Co-transformation frequency was 100% (146/146) for linked genes
and 80% (41/51) for unlinked genes. Co-expression frequency of the bar and
gus genes was 57% (29/51). The co-integration, co-inheritance, and
co-expression of bar, the potato proteinase inhibitor II gene, and gus in
transgenic R0, R1, and R2 plants were confirmed. Localized expression of
the actin 1-GUS protein in the R0 and R1 plants was extensively analyzed by
histochemical and fluorometric assays.
