Phytohormonal networks promote differentiation of fiber initials on pre-anthesis cotton ovules grown in vitro and in planta

• Published in: PloS one 2015-04, Vol.10 (4), p.e0125046-e0125046
• Main Authors: Kim, Hee Jin, Hinchliffe, Doug J, Triplett, Barbara A, Chen, Z Jeffrey, Stelly, David M, Yeater, Kathleen M, Moon, Hong S, Gilbert, Matthew K, Thyssen, Gregory N, Turley, Rickie B, Fang, David D
• Format: Article
• Language: English
• Subjects: 1-Aminocyclopropane-1-carboxylate oxidase; Abscisic acid; Acetic acid; Agricultural production; Arabidopsis; Biology; Biosynthesis; Catabolism; Cell culture; Comparative analysis; Computational Biology; Cotton; Cotton Fiber; Cotton fibers; Cotton trade; Crop yield; Culture techniques; Differentiation; Ethylene; Gene expression; Gene Expression Profiling; Gene Expression Regulation, Plant - drug effects; Genes; Gibberellins; Gossypium - drug effects; Gossypium - genetics; Gossypium - growth & development; Gossypium - metabolism; Gossypium hirsutum; Hydroxylase; Indoleacetic acid; Jasmonic acid; Kinases; Molecular chains; Molecular modelling; Molecular Sequence Annotation; Mutants; Mutation; Ovule - drug effects; Ovule - genetics; Ovule - growth & development; Ovule - metabolism; Ovules; Phenotype; Physiology; Plant Growth Regulators - genetics; Plant Growth Regulators - metabolism; Plant Growth Regulators - pharmacology; Plant hormones; Plants, Genetically Modified; Proteins; Reproducibility of Results; Signaling; Transcriptome
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0125046

The number of cotton (Gossypium sp.) ovule epidermal cells differentiating into fiber initials is an important factor affecting cotton yield and fiber quality. Despite extensive efforts in determining the molecular mechanisms regulating fiber initial differentiation, only a few genes responsible for fiber initial differentiation have been discovered. To identify putative genes directly involved in the fiber initiation process, we used a cotton ovule culture technique that controls the timing of fiber initial differentiation by exogenous phytohormone application in combination with comparative expression analyses between wild type and three fiberless mutants. The addition of exogenous auxin and gibberellins to pre-anthesis wild type ovules that did not have visible fiber initials increased the expression of genes affecting auxin, ethylene, ABA and jasmonic acid signaling pathways within 1 h after treatment. Most transcripts expressed differentially by the phytohormone treatment in vitro were also differentially expressed in the ovules of wild type and fiberless mutants that were grown in planta. In addition to MYB25-like, a gene that was previously shown to be associated with the differentiation of fiber initials, several other differentially expressed genes, including auxin/indole-3-acetic acid (AUX/IAA) involved in auxin signaling, ACC oxidase involved in ethylene biosynthesis, and abscisic acid (ABA) 8'-hydroxylase an enzyme that controls the rate of ABA catabolism, were co-regulated in the pre-anthesis ovules of both wild type and fiberless mutants. These results support the hypothesis that phytohormonal signaling networks regulate the temporal expression of genes responsible for differentiation of cotton fiber initials in vitro and in planta.