title: Early cone setting in Picea abies acrocona is associated with increased transcriptional activity of a MADS box transcription factor.
abstract: Conifers normally go through a long juvenile period, for Norway spruce (Picea abies) around 20 to 25 years, before developing male and female cones. We have grown plants from inbred crosses of a naturally occurring spruce mutant (acrocona). One-fourth of the segregating acrocona plants initiate cones already in their second growth cycle, suggesting control by a single locus. The early cone-setting properties of the acrocona mutant were utilized to identify candidate genes involved in vegetative-to-reproductive phase change in Norway spruce. Poly(A(+)) RNA samples from apical and basal shoots of cone-setting and non-cone-setting plants were subjected to high-throughput sequencing (RNA-seq). We assembled and investigated 33,383 expressed putative protein-coding acrocona transcripts. Eight transcripts were differentially expressed between selected sample pairs. One of these (Acr42124_1) was significantly up-regulated in apical shoot samples from cone-setting acrocona plants, and the encoded protein belongs to the MADS box gene family of transcription factors. Using quantitative real-time polymerase chain reaction with independently derived plant material, we confirmed that the MADS box gene is up-regulated in both needles and buds of cone-inducing shoots when reproductive identity is determined. Our results constitute important steps for the development of a rapid cycling model system that can be used to study gene function in conifers. In addition, our data suggest the involvement of a MADS box transcription factor in the vegetative-to-reproductive phase change in Norway spruce.
authors.affiliation: Department of Plant Biology and Forest Genetics, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-750 07 Uppsala, Sweden.
authors.forename: Daniel
authors.initials: D
authors.lastname: Uddenberg
authors.forename: Johan
authors.initials: J
authors.lastname: Reimegård
authors.forename: David
authors.initials: D
authors.lastname: Clapham
authors.forename: Curt
authors.initials: C
authors.lastname: Almqvist
authors.forename: Sara
authors.initials: S
authors.lastname: von Arnold
authors.forename: Olof
authors.initials: O
authors.lastname: Emanuelsson
authors.forename: Jens F
authors.initials: JF
authors.lastname: Sundström
mesh_terms: D003433:Crosses, Genetic; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D059014:High-Throughput Nucleotide Sequencing; D026161:MADS Domain Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009664:Norway; D010641:Phenotype; D010802:Phylogeny; D028222:Picea / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013548:Sweden
chemical_list: D026161:MADS Domain Proteins; D010940:Plant Proteins