The MaizeDWARF1Encodes a Gibberellin 3-Oxidase and Is Dual Localized to the Nucleus and Cytosol  

Abstract

The maize (Zea mays) gibberellin (GA)-deficient mutant dwarf1 (d1) displays dwarfism and andromonoecy (i.e. forming anthers in the female flower). Previous characterization indicated that the d1 mutation blocked three steps in GA biosynthesis; however, the locus has not been isolated and characterized. Here, we report that D1 encodes a GA 3-oxidase catalyzing the final step of bioactive GA synthesis. Recombinant D1 is capable of converting GA 20 to GA 1 , GA 20 to GA 3 , GA 5 to GA 3 , and GA 9 to GA 4 in vitro. These reactions are widely believed to take place in the cytosol. However, both in vivo GFP fusion analysis and westernblot analysis of organelle fractions using a D1-specific antibody revealed that the D1 protein is dual localized in the nucleus and cytosol. Furthermore, the upstream gibberellin 20-oxidase1 (ZmGA20ox1) protein was found dual localized in the nucleus and cytosol as well. These results indicate that bioactive GA can be synthesized in the cytosol and the nucleus, two compartments where GA receptor Gibberellin-insensitive dwarf protein1 exists. Furthermore, the D1 protein was found to be specifically expressed in the stamen primordia in the female floret, suggesting that the suppression of stamen development is mediated by locally synthesized GAs.

The Maize MID-COMPLEMENTING ACTIVITY Homolog CELL NUMBER REGULATOR13/NARROW ODD DWARF Coordinates Organ Growth and Tissue Patterning

“…To test if GA deficiency is causal to the nod-1 phenotypes, we applied exogenous GA 3 to 2-week-old plants. The treatment rescued the GA biosynthesis-deficient mutant d1 (Chen et al, 2014) but not the GA insensitive D9 mutant (Lawit et al, 2010). In nod-1, GA 3 application caused a small increase in stem height, but failed to rescue the other pleiotropic phenotypes (Supplemental Figures 7E and 7F).…”

nana plant2 Encodes a Maize Ortholog of the Arabidopsis Brassinosteroid Biosynthesis Gene DWARF1, Identifying Developmental Interactions between Brassinosteroids and Gibberellins

“…3-oxidase, and d5, an ent-kaurene synthase, were used in this study (Hedden and Phinney, 1979;Hartwig et al, 2011;Chen et al, 2014). F2 populations from crosses between na2-1 and d5, na2-1 and d1, and na1-1 and d1 segregated for the mutants and effects of the genetic backgrounds.…”

The dioxygenase GIM2 functions in seed germination by altering gibberellin production in Arabidopsis

“…The fusion protein YFP‐GIM2 was observed in the cytoplasm, and it also colocalized in the nucleus with transcription factor ABF2 (Figure C). Indeed, 2OGDs such as GA20ox, GA3ox, and GA2ox were shown previously to localize to the cytoplasm in a number of studies (Sun ; Chen et al ). Thus, we hypothesized that GIM2 might play a role in the GA metabolism pathway.…”