Male sterility in transgenic tobacco plants induced by tapetum-specific deacetylation of the externally applied non-toxic compound N-acetyl-L-phosphinothricin.
A system for the inducible destruction of plant tissues based on the deacetylation of the non-toxic compound N-acetyl-L-phosphinothricin (N-ac-Pt) has been developed. The argE gene product of Escherichia coli, representing a N-acetyl-L-ornithine deacetylase was identified to remove the acetyl-group from N-ac-Pt giving the cytotoxic compound L-phosphinothricin (Pt, glufosinate). Transgenic Nicotiana tabacum plants constitutively expressing the argE gene were constructed. No effect of the bacterial N-acetyl-L-ornithine deacetylase on plant growth and reproduction could be traced. However, application of N-ac-Pt on leaves of the transgenic plants led to the formation of necrotic areas due to the release of Pt. Additionally, due to the uptake of the N-ac-Pt by roots, transgenic shoots grown on medium containing N-ac-Pt bleached within 6-7 days and finally died. Untransformed controls showed no reaction to high amounts of N-ac-Pt applied, either under sterile or under unsterile conditions. In order to construct inducible male-sterile plants, the argE coding region was fused to a DNA fragment carrying sequences homologous to the tobacco TA29 promoter, known to function exclusively in the tapetum. Owing to the tapetum-specific expression of the chimeric gene the application of N-ac-Pt led to empty anthers resulting in male-sterile plants. The sanity of the female reproductive part of the male-sterile flowers could be demonstrated by cross-pollination. Without N-ac-Pt treatment the plants turned out to be completely fertile making fertility restoration in the F1 generation superfluous. The system presented is easy to handle and might be applicable to a wide range of crop plants.
Kriete
G
G
Universität Bielefeld, Fakultät für Biologie, Lehrstuhl für Genetik, Bielefeld, Germany.
Niehaus
K
K
Perlick
A M
AM
Pühler
A
A
Broer
I
I
D000581:Amidohydrolases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D000613:Aminobutyrates / Q000378:metabolism* / Q000633:toxicity*; D001483:Base Sequence; D001711:Biotransformation; D017931:DNA Primers; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005798:Genes, Bacterial; D005966:Glucuronidase / Q000032:analysis / Q000096:biosynthesis; D007246:Infertility; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D009336:Necrosis; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D014026:Nicotiana / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure
D000613:Aminobutyrates; D017931:DNA Primers; C100582:N-acetylphosphinothricin; D005966:Glucuronidase; D000581:Amidohydrolases; C100583:N-acetylphosphinothricin deacetylase; C018732:N-acetylornithine deacetylase