The expression of a Vp1-like gene and seed dormancy in Mesembryanthemum crystallinum.
Seeds of the common ice plant (Mesembryanthemum crystallinum) germinate in distinct sub-populations over a time period of more than 4 weeks following imbibition. Distinguishing early (E)- and late (L)-germinating seeds is the expression of a homologue of the transcriptional activator VP1. The deduced amino acid sequence of ice plant VP1 (MVP1) is 39% identical (50% similar) to the sequence of the Arabidopsis VP1 homologue, ABI3. The amount of Mvp1 mRNA, transcribed from a single gene, is different in E and L seeds after water uptake. The levels of the Mvp1 transcripts are very low in immature and mature seeds and they increased during 6 days of imbibition. This expression profile of Mvp1 is different from known Vp1/ABI3-like genes in other plants. Cycloheximide (at 35 microM) abolishes the increase of Mvp1, and L seeds are turned into E seeds, which develop normally when the inhibitor is applied for a short time during imbibition. E seeds treated for the same time period are developmentally impaired and show no radicle elongation. We suggest that the presence and late disappearance of Mvp1 in L seeds is responsible for dormancy and after-ripening of late-germinating ice plant seeds.
Fukuhara
T
T
Department of Biochemistry, University of Arizona, Biosciences West, Tucson, AZ 85721-0088, USA. fuku@cc.tuat.ac.jp
Bohnert
H J
HJ
D000595:Amino Acid Sequence; D003513:Cycloheximide / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics*; D017343:Genes, Plant; D018525:Germination; D008969:Molecular Sequence Data; D063245:Plant Development; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D010944:Plants / Q000187:drug effects / Q000235:genetics*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D012639:Seeds / Q000235:genetics / Q000254:growth & development*; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; D010940:Plant Proteins; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; D003513:Cycloheximide