Thesis (M.Sc.)--Chulalongkorn University, 2000

Gus gene regulated by Arabidopsis TGG1 promoter, showing the specific expression in Arabidopsis (Arabidopsis thaliana) guard cells, was transformed into tobacco (Nicotiana tabacum L.), petunia (Petunia hybrida L.) and potato (Solanum tuberosum L.), the Solanaceous plant species containing no TGG enzyme system, by Agrobacterium tumefaciens LBA 4404 ProA1.1. Ten independent transgenic tobacco lines, three transgenic petunia lines and nine transgenic potato lines were obtained. The guard cell specific expression was detected in cotyledons, leaves, pedicels, sepals, petals, anthers, and styles of the transgenic tobacco and in leaves, sepals, petals, anthers of transgenic petunia. No guard cell specific expression was found in leaves and stems of transgenic potato. The quantitative analysis of gus gene expression indicated the highest GUS activity in cotyledons of 15-day-after germination T2 transgenic tobacco plant. For the transgenic petunia, the highest GUS activity was detected in pistils. Low level of GUS activity in leaves and stems of all transgenic potato lines was fluorometrically detected, but it could not be detected histochemically. The younger tissues had the higher level of GUS activity than the older ones in both vegetative and reproductive organs. The aseptically grown transgenic tobacco had the higher level of GUS activity than the soil grown transgenic ones. These data suggest the species, age and environmental effect on Arabidopsis TGG1 promoter experssion.