title: The Hairless Stem Phenotype of Cotton (Gossypium barbadense) Is Linked to a Copia-Like Retrotransposon Insertion in a Homeodomain-Leucine Zipper Gene (HD1).
abstract: Cotton (Gossypium) stem trichomes are mostly single cells that arise from stem epidermal cells. In this study, a homeodomain-leucine zipper gene (HD1) was found to cosegregate with the dominant trichome locus previously designated as T1 and mapped to chromosome 6. Characterization of HD1 orthologs revealed that the absence of stem trichomes in modern Gossypium barbadense varieties is linked to a large retrotransposon insertion in the ninth exon, 2565 bp downstream from the initial codon in the At subgenome HD1 gene (At-GbHD1). In both the At and Dt subgenomes, reduced transcription of GbHD1 genes is caused by this insertion. The disruption of At-HD1 further affects the expression of downstream GbMYB25 and GbHOX3 genes. Analyses of primitive cultivated accessions identified another retrotransposon insertion event in the sixth exon of At-GbHD1 that might predate the previously identified retrotransposon in modern varieties. Although both retrotransposon insertions results in similar phenotypic changes, the timing of these two retrotransposon insertion events fits well with our current understanding of the history of cotton speciation and dispersal. Taken together, the results of genetics mapping, gene expression and association analyses suggest that GbHD1 is an important component that controls stem trichome development and is a promising candidate gene for the T1 locus. The interspecific phenotypic difference in stem trichome traits also may be attributable to HD1 inactivation associated with retrotransposon insertion.
authors.affiliation: Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agriculture and Food Science, Zhejiang A&F University, Lin'an 311300, China.
authors.forename: Mingquan
authors.initials: M
authors.lastname: Ding
authors.affiliation: State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China.
authors.forename: Wuwei
authors.initials: W
authors.lastname: Ye
authors.affiliation: Nanosphere, Inc., 4088 Commercial Drive, Northbrook, Illinois 60062.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Lin
authors.affiliation: Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agriculture and Food Science, Zhejiang A&F University, Lin'an 311300, China.
authors.forename: Shae
authors.initials: S
authors.lastname: He
authors.affiliation: State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China.
authors.forename: Xiongming
authors.initials: X
authors.lastname: Du
authors.affiliation: Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agriculture and Food Science, Zhejiang A&F University, Lin'an 311300, China College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Aiqun
authors.initials: A
authors.lastname: Chen
authors.affiliation: Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agriculture and Food Science, Zhejiang A&F University, Lin'an 311300, China.
authors.forename: Yuefen
authors.initials: Y
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agriculture and Food Science, Zhejiang A&F University, Lin'an 311300, China.
authors.forename: Fen
authors.initials: F
authors.lastname: Yang
authors.affiliation: Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agriculture and Food Science, Zhejiang A&F University, Lin'an 311300, China.
authors.forename: Yurong
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agriculture and Food Science, Zhejiang A&F University, Lin'an 311300, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Plant Genome Mapping Laboratory, University of Georgia, Athens, Georgia 30605.
authors.forename: Xiyin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Plant Genome Mapping Laboratory, University of Georgia, Athens, Georgia 30605 paterson@uga.edu jkrong@yahoo.com.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Paterson
authors.affiliation: Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agriculture and Food Science, Zhejiang A&F University, Lin'an 311300, China paterson@uga.edu jkrong@yahoo.com.
authors.forename: Junkang
authors.initials: J
authors.lastname: Rong
mesh_terms: D002874:Chromosome Mapping; D005801:Genes, Homeobox; D049810:Genetic Speciation; D003368:Gossypium / Q000235:genetics*; D016350:Leucine Zippers; D016254:Mutagenesis, Insertional; D010641:Phenotype; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics*; D018547:Plant Stems / Q000235:genetics; D018626:Retroelements / Q000235:genetics*
chemical_list: D010940:Plant Proteins; D018626:Retroelements
keywords: Gossypium barbadense; T1 locus; Ty1 retrotransposon element; glabrous stem; homeodomain-leucine zipper gene (HD1)