Expression of two genes encoding gibberellin 2- and 3-oxidases in developing seeds of Phaseolus coccineus.
We have isolated PcGA3ox1, a cDNA clone from developing runner bean (Phaseolus coccineus) seeds that shows significant amino acid homology with the gibberellin (GA) 3-oxidases. A recombinant fusion protein of PcGA3ox1 converted GA20 and GA9 to GA1 and GA4, respectively. In situ hybridization results showed that transcripts of this gene accumulate specifically within the suspensor of globular-stage embryos. PcGA3ox1 mRNA begins to accumulate in the epidermal cells of the embryo proper and is also detectable in the endosperm during the transition from globular- to heart-stage embryos. PcGA3ox1 transcripts were localized exclusively in the cotyledons from the early cotyledonary stage up to the cotyledonary stage. Transcripts of the previously cloned GA 2-oxidase (PcGA2ox1) from developing seeds of runner bean were found primarily within the suspensor neck region from the late globular stage up to the heart stage. PcGA2ox1 mRNA was detectable in the whole suspensor from the early cotyledonary stage, and was found in the inner layer of integuments at the cotyledonary stage. Soluble enzyme preparations made from suspensors and embryos at two stages of embryogenesis (the heart and cotyledonary stages) were incubated with [14C]GA20 and [14C]GA1. Only young suspensor preparations converted GA20 to GA1 and GA5. Both suspensor preparations converted GA1 to GA8. Both embryo preparations converted GA20 to GA1, but were unable to convert GA1 to GA8.
Solfanelli
Cinzia
C
Dipartimento di Biologia delle Piante Agrarie, Università di Pisa, Via Mariscoglio, 34, 56124 Pisa, Italy.
Ceron
Francesca
F
Paolicchi
Fabio
F
Giorgetti
Lucia
L
Geri
Chiara
C
Ceccarelli
Nello
N
Kamiya
Yuji
Y
Picciarelli
Piero
P
D002474:Cell-Free System; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D018745:Genome, Plant; D017403:In Situ Hybridization; D006899:Mixed Function Oxygenases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D027805:Phaseolus / Q000196:embryology* / Q000235:genetics*; D010802:Phylogeny; D034443:RNA Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000196:embryology* / Q000235:genetics*; D014158:Transcription, Genetic
D012333:RNA, Messenger; D018749:RNA, Plant; D006899:Mixed Function Oxygenases; C121463:gibberellin 2-dioxygenase; C108186:gibberellin 3beta-hydroxylase