Electroporation of maize embryogenic calli with the trehalose-6-phosphate synthase gene from Arabidopsis thaliana

摘要

Trehalose is a non-reducing disaccharide of glucose that occurs in a large number of organisms,playing an important role in desiccation and heat stress protection. Trehalose accumulation has proven to bean effective way of increasing drought tolerance in both model plants such as tobacco and important cropssuch as potato or rice. In this work we aim to genetically engineer maize with the Arabidopsis thalianatrehalose phosphate synthase gene (AtTPSl), involved in trehalose biosynthesis via electroporation. A cassette harboring the AtTPSl gene under the control ofthe CaMV35S promoter and the Bialaphos resistance gene Bar as a selective agent was inserted in the plasmid vector pGreen0229 and used to transform maizeinbred line Pa91 via electroporation. Fifteen putative transgenic plants (TO generation) were obtained.Transgene integration in TO plants was analyzed by Southern-blot analysis. TO plants had normal phenotypes, although smaller than wild type plants. Contraryto wild type plants, when sexual organs emerged, tassels appeared at least 15 days earlier than ears in thesame plant, rendering impossible the self-pollination of the TO plant. These plants were then crossed with wildtype plants and in some cases Tl seeds were obtained. Tl seeds presented deformities, especially the lack ofendosperm, but it was still possible to germinate some of these seeds. The so obtained plants were tested byNorthern blot but no AtTPSl gene expression was detected, a fact possibly due to the incomplete insertion of the AtTPSl gene or an extremely low geneexpression level.