Pleiotropic effects in transgenic tobacco plants expressing the oryzacystatin I gene

A study was undertaken to evaluate possible phenotypic alterations in trans genic tobacco (Nicotiana tabacum L, cv, Xanthi) plants expressing the oryza cystatin I gene. Morphophysiologic parameters, such as growth rate, biomass , and leaf, flower, and fruit characteristics were analyzed. Transgenic pla nts overexpressing the cysteine proteinase inhibitor showed increased growt h rate and dry weight, earlier flowering, and increased numbers of flowers and seeds, These pleiotropic effects were correlated with expression level of oryzacystatin I in transgenic lines. The results suggest that oryzacysta tin I disrupts the normal activity of cysteine proteinases, which are invol ved in important physiological processes.