title: Accumulation of genome-specific transcripts, transcription factors and phytohormonal regulators during early stages of fiber cell development in allotetraploid cotton.
abstract: Gene expression during the early stages of fiber cell development and in allopolyploid crops is poorly understood. Here we report computational and expression analyses of 32 789 high-quality ESTs derived from Gossypium hirsutum L. Texas Marker-1 (TM-1) immature ovules (GH_TMO). The ESTs were assembled into 8540 unique sequences including 4036 tentative consensus sequences (TCs) and 4504 singletons, representing approximately 15% of the unique sequences in the cotton EST collection. Compared with approximately 178 000 existing ESTs derived from elongating fibers and non-fiber tissues, GH_TMO ESTs showed a significant increase in the percentage of genes encoding putative transcription factors such as MYB and WRKY and genes encoding predicted proteins involved in auxin, brassinosteroid (BR), gibberellic acid (GA), abscisic acid (ABA) and ethylene signaling pathways. Cotton homologs related to MIXTA, MYB5, GL2 and eight genes in the auxin, BR, GA and ethylene pathways were induced during fiber cell initiation but repressed in the naked seed mutant (N1N1) that is impaired in fiber formation. The data agree with the known roles of MYB and WRKY transcription factors in Arabidopsis leaf trichome development and the well-documented phytohormonal effects on fiber cell development in immature cotton ovules cultured in vitro. Moreover, the phytohormonal pathway-related genes were induced prior to the activation of MYB-like genes, suggesting an important role of phytohormones in cell fate determination. Significantly, AA sub-genome ESTs of all functional classifications including cell-cycle control and transcription factor activity were selectively enriched in G. hirsutum L., an allotetraploid derived from polyploidization between AA and DD genome species, a result consistent with the production of long lint fibers in AA genome species. These results suggest general roles for genome-specific, phytohormonal and transcriptional gene regulation during the early stages of fiber cell development in cotton allopolyploids.
authors.affiliation: Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77843, USA.
authors.forename: S
authors.initials: S
authors.lastname: Samuel Yang
authors.forename: Foo
authors.initials: F
authors.lastname: Cheung
authors.forename: Jinsuk J
authors.initials: JJ
authors.lastname: Lee
authors.forename: Misook
authors.initials: M
authors.lastname: Ha
authors.forename: Ning E
authors.initials: NE
authors.lastname: Wei
authors.forename: Sing-Hoi
authors.initials: SH
authors.lastname: Sze
authors.forename: David M
authors.initials: DM
authors.lastname: Stelly
authors.forename: Peggy
authors.initials: P
authors.lastname: Thaxton
authors.forename: Barbara
authors.initials: B
authors.lastname: Triplett
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Town
authors.forename: Z
authors.initials: Z
authors.lastname: Jeffrey Chen
mesh_terms: D029681:Arabidopsis Proteins; D016000:Cluster Analysis; D019295:Computational Biology; D020224:Expressed Sequence Tags; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D003368:Gossypium / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011123:Polyploidy; D020598:Proto-Oncogene Proteins c-myb / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: C511988:ATR1 protein, Arabidopsis; D029681:Arabidopsis Proteins; C511989:CPC protein, Arabidopsis; D010937:Plant Growth Regulators; D010940:Plant Proteins; D020598:Proto-Oncogene Proteins c-myb; D014157:Transcription Factors