Ectopic expression of BABY BOOM triggers a conversion from vegetative to embryonic growth.
The molecular mechanisms underlying the initiation and maintenance of the embryonic pathway in plants are largely unknown. To obtain more insight into these processes, we used subtractive hybridization to identify genes that are upregulated during the in vitro induction of embryo development from immature pollen grains of Brassica napus (microspore embryogenesis). One of the genes identified, BABY BOOM (BBM), shows similarity to the AP2/ERF family of transcription factors and is expressed preferentially in developing embryos and seeds. Ectopic expression of BBM in Arabidopsis and Brassica led to the spontaneous formation of somatic embryos and cotyledon-like structures on seedlings. Ectopic BBM expression induced additional pleiotropic phenotypes, including neoplastic growth, hormone-free regeneration of explants, and alterations in leaf and flower morphology. The expression pattern of BBM in developing seeds combined with the BBM overexpression phenotype suggests a role for this gene in promoting cell proliferation and morphogenesis during embryogenesis.
Boutilier
Kim
K
Plant Research International, Wageningen, The Netherlands. k.a.boutilier@plant.wag-ur.nl
Offringa
Remko
R
Sharma
Vijay K
VK
Kieft
Henk
H
Ouellet
Thérèse
T
Zhang
Lemin
L
Hattori
Jiro
J
Liu
Chun-Ming
CM
van Lammeren
André A M
AA
Miki
Brian L A
BL
Custers
Jan B M
JB
van Lookeren Campagne
Michiel M
MM
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000196:embryology / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D029688:Brassica napus / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D002455:Cell Division; D004268:DNA-Binding Proteins; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D012639:Seeds / Q000235:genetics* / Q000254:growth & development; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
C499534:APETALA2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; D014157:Transcription Factors; C093680:ethylene-responsive element binding protein