Abstract
Immunomodulation is a means to modulate an organism's function by antibody production. Previously, we have succeeded in obtaining GA-deficient phenotypes in arabidopsis and tobacco by expressing single-chain variable fragment (scFv) against bioactive gibberellin (GA), GA4/1. Likewise we have introduced a scFv against GA24/19, biosynthetic precursors of bioactive GAs, into tobacco, which also showed a dwarf phenotype. In arabidopsis, however, the scFv was not well accumulated and its effect was obscure. In this study, we expressed the same scFv as a fusion with GFP. Consequently, transgenic arabidopsis plants accumulated the fusion protein at high level, and showed apparent GA-deficient phenotypes. The phenotype was clear especially in bolting stage, such as late flowering and early completion of the primary shoot growth. These phenotypes were different from those observed for lines expressing anti-GA4/1 scFv. The different mode of immunomodulation, inhibition of GA action and GA biosynthesis, may reflect on the differential phenotypes.
