Auxin regulates the promoter of the root-inducing rolB gene of Agrobacterium rhizogenes in transgenic tobacco.
The regulation in tobacco of the rolB and rolC promoters of Agrobacterium rhizogenes pRi 1855 TL-DNA was studied by using the beta-glucuronidase (GUS) reporter system in transgenic plants. A 20- to 100-fold increase of GUS activity was selectively induced by auxin in rolB-GUS transformed mesophyll protoplasts, whereas this auxin-dependent increase was only 5-fold in rolC-GUS protoplasts. Moreover, both gene fusions exhibited similar tissue-specific expression in aerial parts but different patterns in roots. The spatial pattern of rolB-GUS expression could be strongly modified by the addition of exogenous auxin, further suggesting that auxin plays a central role in the regulation of the rolB promoter in tobacco. The tissue-specific and auxin-dependent regulation of the rolB promoter is discussed in relation to the effects of the rolB gene on rhizogenesis and on cellular responses to auxin.
Maurel
C
C
Institut des Sciences Végétales, C.N.R.S., Gif-sur-Yvette, France.
Brevet
J
J
Barbier-Brygoo
H
H
Guern
J
J
Tempé
J
J
D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D007210:Indoleacetic Acids / Q000494:pharmacology*; D007700:Kinetics; D009928:Organ Specificity / Q000235:genetics; D010947:Plants, Toxic; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D012231:Rhizobium / Q000235:genetics*; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000382:microbiology*; D014162:Transfection; D014170:Transformation, Genetic
D004269:DNA, Bacterial; D007210:Indoleacetic Acids; C036483:T-DNA; D005966:Glucuronidase