Early Cone Setting in Picea Abies Acrocona Is Associated With Increased Transcriptional Activity of a MADS Box Transcription Factor

Plant Physiol. 2013 Feb;161(2):813-23. doi: 10.1104/pp.112.207746. Epub 2012 Dec 7.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crosses, Genetic
  • Gene Expression Profiling*
  • Gene Expression Regulation, Developmental
  • Gene Expression Regulation, Plant
  • High-Throughput Nucleotide Sequencing
  • MADS Domain Proteins / classification
  • MADS Domain Proteins / genetics*
  • MADS Domain Proteins / metabolism
  • Mutation
  • Norway
  • Phenotype
  • Phylogeny
  • Picea / genetics*
  • Picea / growth & development
  • Picea / metabolism
  • Plant Leaves / genetics
  • Plant Leaves / growth & development
  • Plant Leaves / metabolism
  • Plant Proteins / classification
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Plant Shoots / genetics
  • Plant Shoots / growth & development
  • Plant Shoots / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sweden

Substances

  • MADS Domain Proteins
  • Plant Proteins