Phytohormonal networks promote differentiation of fiber initials on pre-anthesis cotton ovules grown in vitro and in planta.
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.
Cotton Fiber Bioscience Research Unit, USDA-ARS-SRRC, New Orleans, Louisiana, United States of America.
Hee Jin
HJ
Kim
Cotton Fiber Bioscience Research Unit, USDA-ARS-SRRC, New Orleans, Louisiana, United States of America.
Doug J
DJ
Hinchliffe
Cotton Fiber Bioscience Research Unit, USDA-ARS-SRRC, New Orleans, Louisiana, United States of America.
Barbara A
BA
Triplett
Institute for Cellular and Molecular Biology and Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, Texas, United States of America.
Z Jeffrey
ZJ
Chen
Department of Soil and Crop Science, Texas A&M University, College Station, Texas, United States of America.
David M
DM
Stelly
Plains Area, USDA-ARS, Fort Collins, Colorado, United States of America.
Kathleen M
KM
Yeater
Cotton Fiber Bioscience Research Unit, USDA-ARS-SRRC, New Orleans, Louisiana, United States of America.
Hong S
HS
Moon
Cotton Fiber Bioscience Research Unit, USDA-ARS-SRRC, New Orleans, Louisiana, United States of America.
Matthew K
MK
Gilbert
Cotton Fiber Bioscience Research Unit, USDA-ARS-SRRC, New Orleans, Louisiana, United States of America.
Gregory N
GN
Thyssen
Crop Genetics Research Unit, USDA-ARS, Stoneville, Mississippi, United States of America.
Rickie B
RB
Turley
Cotton Fiber Bioscience Research Unit, USDA-ARS-SRRC, New Orleans, Louisiana, United States of America.
David D
DD
Fang
D019295:Computational Biology; D032561:Cotton Fiber; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D003368:Gossypium / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D058977:Molecular Sequence Annotation; D009154:Mutation; D056771:Ovule / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D010641:Phenotype; D010937:Plant Growth Regulators / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D030821:Plants, Genetically Modified; D015203:Reproducibility of Results; D059467:Transcriptome
D010937:Plant Growth Regulators