title: Evaluation of the hormonal state of columnar apple trees (Malus x domestica) based on high throughput gene expression studies.
abstract: The columnar phenotype of apple trees (Malus x domestica) is characterized by a compact growth habit with fruit spurs instead of lateral branches. These properties provide significant economic advantages by enabling high density plantings. The columnar growth results from the presence of a dominant allele of the gene Columnar (Co) located on chromosome 10 which can appear in a heterozygous (Co/co) or homozygous (Co/Co) state. Although two deep sequencing approaches could shed some light on the transcriptome of columnar shoot apical meristems (SAMs), the molecular mechanisms of columnar growth are not yet elaborated. Since the influence of phytohormones is believed to have a pivotal role in the establishment of the phenotype, we performed RNA-Seq experiments to study genes associated with hormone homeostasis and clearly affected by the presence of Co. Our results provide a molecular explanation for earlier findings on the hormonal state of columnar apple trees. Additionally, they allow hypotheses on how the columnar phenotype might develop. Furthermore, we show a statistically approved enrichment of differentially regulated genes on chromosome 10 in the course of validating RNA-Seq results using additional gene expression studies.
authors.affiliation: Department of Molecular Genetics, University of Mainz, 55128 Mainz, Germany. clemens.krost@dzne.de
authors.forename: Clemens
authors.initials: C
authors.lastname: Krost
authors.forename: Romina
authors.initials: R
authors.lastname: Petersen
authors.forename: Stefanie
authors.initials: S
authors.lastname: Lokan
authors.forename: Bastienne
authors.initials: B
authors.lastname: Brauksiepe
authors.forename: Peter
authors.initials: P
authors.lastname: Braun
authors.forename: Erwin R
authors.initials: ER
authors.lastname: Schmidt
mesh_terms: D000483:Alleles; D032461:Chromosomes, Plant / Q000235:genetics; D019295:Computational Biology; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D017343:Genes, Plant / Q000235:genetics*; D059014:High-Throughput Nucleotide Sequencing; D006706:Homeostasis; D027845:Malus / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D018519:Meristem / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D008958:Models, Molecular; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010937:Plant Growth Regulators / Q000235:genetics / Q000502:physiology*; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D018749:RNA, Plant / Q000737:chemistry / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017423:Sequence Analysis, RNA; D059467:Transcriptome; D014197:Trees
chemical_list: D010937:Plant Growth Regulators; D018749:RNA, Plant