Expression of the Fusarium resistance gene I-2 colocalizes with the site of fungal containment.
The tomato resistance gene I-2 is one of at least six members of a gene family that are expressed at low levels in the roots, stems and leaves of young tomato plants. Plants transformed with constructs containing a functional I-2 promoter fused to the beta-glucuronidase (GUS) reporter gene were used in detailed expression studies. Highest GUS activity was found in stems of young tomato plants. Histochemical analysis revealed that the I-2 promoter drives expression of the reporter gene in vascular tissue of fruits, leaves, stems and mature roots. In younger roots, expression was most abundant at the base of lateral root primordia. Microscopical analysis of young tomato plants revealed expression in tissue surrounding the xylem vessels. We show that in resistant plants, fungal growth into this region of the vascular tissue is prevented, suggesting a correlation with the I-2-mediated resistance response.
Section for Plant Pathology, Swammerdam Institute for Life Sciences, BioCentrum Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands.
J J
JJ
Mes
A A
AA
van Doorn
J
J
Wijbrandi
G
G
Simons
B J
BJ
Cornelissen
M A
MA
Haring
D001483:Base Sequence; D005670:Fusarium / Q000472:pathogenicity*; D017343:Genes, Plant; D017930:Genes, Reporter; D005966:Glucuronidase / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics; D018551:Solanum lycopersicum / Q000235:genetics* / Q000382:microbiology*; D008969:Molecular Sequence Data; D005810:Multigene Family; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
D011994:Recombinant Proteins; D005966:Glucuronidase