The temporal and spatial expression of three promoters was investigated in transgenic rice plants using promoter-β-glucuronidase (gusA) reporter gene fusions. The promoters studied were ubiquitin-1 (UBI-1) of Zea mays, Cauliflower Mosaic Virus 35S gene (CaMV35S) and a tubulin gene (TUB-1) of Arabidopsis thaliana. The TUB-1 promoter provided 7.32-fold more GUS activity in roots relative to tillers. This was significantly different from the corresponding value of 2.82-fold for CaMV35S but not from that of 4.55-fold for UBI-1, activity of both promoters was higher in the root tips and zone of elongation than mature roots. This younger root tissue represented a declining proportion of the expanding root system with time. Older tissue expressing GUS under control of the TUB-1 promoter showed a steeper decline in activity with time than occurred with the UBI-1 promoter. Nematode infection did not alter the overall pattern of expression from the two promoters, except that the giant cells induced by Meloidogyne incognita retained TUB-1 promoter activity as roots matured. Pratylenchus zeae invaded older root regions than M. incognita and no changes in promoter activity were detected where it fed. The results suggest the TUB-1 promoter has characteristics that favour its use for delivering anti-feedants, such as cysteine proteinase inhibitors, to M. incognita.
Green, J.; Vain, P.; Fearnehough, M.T.; Worland, B.; Snape, J.W.; Atkinson, H.J. Analysis of the expression patterns of the Arabidopsis thaliana tubulin-1 and Zea mays ubiquitin-1 promoters in rice plants in association with nematode infection. Physiological and Molecular Plant Pathology (2002) 60 (4) 197-205. [DOI: 10.1006/pmpp.2002.0390]