Up-regulation of a homeodomain-leucine zipper gene HD-1 contributes to trichome initiation and development in cotton

Abstract

Plant trichomes originate from epidermal cells. In this work, we demonstrated that a homeodomain-leucine zipper gene, Gh_A06G1283 (GhHD-1A), was related to the leaf trichome trait in allotetraploid cotton and could be a candidate gene for the T 1 locus. The ortholog of GhHD-1A in the hairless accession Gossypium barbadense cv. Hai7124 was interrupted by a long terminal repeat (LTR) retrotransposon, while GhHD-1A worked well in the hairy accession G. hirsutum acc. T586. Sequence and phylogenetic analysis showed that GhHD-1A belonged to the HD-Zips IV gene family, which mainly regulated epidermis hair development in plants. Silencing of GhHD-1A and its homoeologs GhHD-1D in allotetraploid T586 and Hai7124 could significantly reduce the density of leaf hairs and affect the expression levels of other genes related to leaf trichome formation. Further analysis found that GhHD-1A mainly regulated trichome initiation on the upper epidermal hairs of leaves in cotton, while the upregulated expression of GhHD-1A in different organs/tissues also altered epidermal trichome development. This study not only helps to unravel the important roles of GhHD-1A in regulating trichome initiation in cotton, but also provides a reference for exploring the different forms of trichome development in plants.

Genetic Identification and Transcriptome Analysis of Lintless and Fuzzless Traits in Gossypium arboreum L.

“…Partial silencing of both homoeologs of HD-1 in tetraploid G. hirsutum resulted in a glabrous phenotype and delayed the timing of fibre initiation [15]. However, the hairless stem and leaf phenotype observed in G. barbadense is believed to be caused by a retrotransposon insertion in GbHD-1_At [17,18], making it nonfunctional, and GbHD-1_Dt might only be responsible for trichomes on the lower side of leaves and new buds [18]. In this study, we identified GaHD-1 as a potential candidate gene of the Ga_lintless locus responsible for both the glabrous and lintless phenotypes of the G. arboreum accession A2_106.…”

“…Previous research in G. hirsutum has identified five major loci (T 1 -T 5 ) for the leaf/stem trichome trait [13]; among them, T 1 was located on chromosome A06 (Chr06) [14]. A homeodomain-leucine zipper gene HD-1 is thought to be the causative gene for T 1 [10,[15][16][17][18]. A long terminal repeat retrotransposon insertion in GbHD-1_At results in a lack of pubescence on the stem and leaf epidermis in G. barbadense [17][18][19].…”

“…A homeodomain-leucine zipper gene HD-1 is thought to be the causative gene for T 1 [10,[15][16][17][18]. A long terminal repeat retrotransposon insertion in GbHD-1_At results in a lack of pubescence on the stem and leaf epidermis in G. barbadense [17][18][19]. The silencing of GhHD-1 by RNAi significantly reduced trichome density and delayed the timing of fibre initiation, indicating that the underlying mechanisms regulating trichome and fibre initiation might share some common pathways [15].…”

Genomic Insight into Differentiation and Selection Sweeps in the Improvement of Upland Cotton

“…A similar pattern of selection sweeps was observed in At sub-genome, where modern cultivars showed higher selection peaks than obsolete cultivars. The annotations represent FQ = Fibre quality [28][29][30][31][32], FY = Fibre yield [30], SBN = Sympodial branch node and EM = Early maturity [31,33,34]…”

Genomic insight into the biogeographic history, divergence, and adaptive potential ofG. purpurascens, a forgotten landrace ofG. hirsutum

“…To further understand the genetic basis of these domestication sweeps, we mapped these selection sweeps with previously known QTLs. Some of the selection sweeps overlapped with previously reported QTL hotspots for multiple traits, i.e., for fiber quality (Liu, Zhang et al, 2016, Liu, Teng et al, 2017, Tang, Teng et al, 2015, Wang, Guo et al, 2006, Wang, Zhu et al, 2012, maturity (Ding, Ye et al, 2015, Niu, Cai et al, 2018, yield traits (Liu et al, 2017). Whole-genome duplication (polyploidy) provides the raw material for adaption (Hollister, 2015).…”