Timing of the maternal-to-zygotic transition during early seed development in maize.
In animals, early embryonic development is largely dependent on maternal transcripts synthesized during gametogenesis. Recent data in plants also suggest maternal control over early seed development, but the actual timing of zygotic genome activation is unclear. Here, we analyzed the timing of the maternal-to-zygotic transition during early Zea mays seed development. We show that for 16 genes expressed during early seed development, only maternally inherited alleles are detected during 3 d after fertilization in both the embryo and the endosperm. Microarray analyses of precocious embryonic development in apomictic hybrids between maize and its wild relative, Tripsacum, demonstrate that early embryo development occurs without significant quantitative changes to the transcript population in the ovule before fertilization. Precocious embryo development is also correlated with a higher proportion of polyadenylated mRNA in the ovules. Our data suggest that the maternal-to-zygotic transition occurs several days after fertilization. By contrast, novel transcription accompanies early endosperm development, indicating that different mechanisms are involved in the initiation of endosperm and embryo development.
Grimanelli
Daniel
D
Institut de Recherche pour le Développement, Unité Mixte de Recherche 5096, 34394 Montpellier, France. grimanelli@mpl.ird.fr
Perotti
Enrico
E
Ramirez
Jorge
J
Leblanc
Olivier
O
D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D010063:Ovum / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D023121:RNA, Messenger, Stored / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000196:embryology / Q000235:genetics*; D013997:Time Factors; D015533:Transcriptional Activation / Q000235:genetics; D003313:Zea mays / Q000196:embryology* / Q000235:genetics*; D015053:Zygote / Q000254:growth & development* / Q000378:metabolism
D010940:Plant Proteins; D012333:RNA, Messenger; D023121:RNA, Messenger, Stored