The loss-of-function GLABROUS 3 mutation in cucumber is due to LTR-retrotransposon insertion in a class IV HD-ZIP transcription factor gene CsGL3 that is epistatic over CsGL1

• DOI: 10.1186/s12870-015-0693-0
• Publication Date: 2015-12-29T15:24:00Z
• Authors: Yupeng Pan; Kailiang Bo; Zhihui Cheng; Yiqun Weng
• Keywords: Retrotransposon; Epistasis; Loss function

Trichomes, developed from the protodermal cells (the outermost cell layer of embryo), are hair-like structures covering aerial parts plants. The genetic network regulating trichome development has been extensively studied and well understood in model species Arabidopsis thaliana, which bears unicellular, non-glandular branched trichomes. However, little is known about molecular basis organogenesis multi-cellular trichomes plant like cucumber (Cucumis sativus L.), likely different Arabidopsis. We identified a new mutant exhibited completely glabrous phenotype on all organs. Genetic analysis indicated that was inherited as single recessive gene, csgl3. Fine mapping delimited csgl3 locus into 68.4 kb region with 12 predicted genes. analysis, sequence alignment allelic variation survey natural populations Csa6G514870 encoding class IV homeodomain-associated leucine zipper (HD-ZIP) transcription factor only candidate for CsGL3, 5188 bp length 10 exons. Gene expression revealed loss-of-function CsGL3 due to insertion 5-kb long terminal repeat (LTR) retrotransposon 4th exon CsGL3. Linkage segregating population gene CsGL1 genes csgl1, csgl3, csgl1 + 3 backgrounds uncovered interactions between two Phylogenetic among 28 HD-ZIP protein sequences five placed same clade 7 other members play important roles initiation. mutation controlled by phenotypically genetically distinct previously reported mutants csgl2. an autonomous, active, I transposable element factor. epistatic CsGL1. seemed initiation whereas may act downstream pathway(s). Findings present study provide insights control cucumber.