Obtusifoliol-14a-demethylase (CYP51) is implicated in plant sterol biosynthesis. An Arabidopsis expressed sequence tag encoding a CYP51 was used as a probe to isolate Nicotiana tabacum L. cDNAs. Two types of cDNA clones were identi®ed. Nt CYP51-1 and Nt CYP51-2 shared 97% identity together and around 75% with other plant CYP51s. The function of the encoded enzyme has been demonstrated in planta...

In eukaryotes, manganese superoxide dismutase is a nuclear-encoded protein that scavenges superoxide radicals in the mitochondrial matrix. We have isolated two manganese superoxide dismutase genes from Nicotiana plumbaginifolia L. and fused the 5' upstream regulatory region of these genes to the beta-glucuronidase reporter gene. The two gene fusions displayed a differential tissue specificity i...

In Nicotiana glutinosa L. formation of local lesions on lower leaves inoculated with tobacco mosaic virus increased the susceptibility of the upper leaves to infection in a subsequent inoculation. The increase in susceptibility was detected as an increase of up to 3"5-fold in the number of lesions produced on the upper leaf and a corresponding increase in the amount of virus RNA synthesized. Th...