Fine mapping identifies CsGCN5 encoding a histone acetyltransferase as putative candidate gene for tendril-less1 mutation (td-1) in cucumber

Abstract

Next-generation sequencing-aided map-based cloning delimited the cucumber tendril - less1 ( td - 1 ) locus into a 190.7-kb region in chromosome 6 harboring a putative, novel-function candidate gene encoding a histone acetyltransferase ( CsGCN5 ). The tendril initiated from the lateral meristem is an important and characteristic organ for the species in the Cucurbitaceae family including cucumber (Cucumis sativus L.). While the tendril has its evolutionary significance, it also poses a nuisance in cucumber cultivation under protected environments in which tendril-less cucumber has its advantages. From an EMS mutagenesis population, we identified a tendril-less mutant B007, which was controlled by a recessive gene td-1. Through next-generation sequencing-aided map-based cloning, we show CsGCN5 (Cucumis sativus GENERAL CONTROL NONDEREPRESSIBLE 5), a cucumber gene for a histone acetyltransferase as the most possible candidate for td-1. A non-synonymous SNP in the first exon of CsGCN5 resulted in an amino-acid substitution from Asp (D) in the wild type to Asn (N) in the tendril-less mutant. The candidacy of CsGCN5 was further confirmed by multiple lines of evidence in both biparental and natural cucumber populations. Non-significant expression of CsGCN5 in multiple organs was found between the wild type and the mutant. CsGCN5 exhibited strong expression in the tendril of wild-type plants suggesting its important roles in growth and development of plant tendrils. The identification and characterization of the td-1 mutant from the present study provided a useful tool in understanding the molecular mechanisms of tendril organogenesis and investigation of novel functions of the histone acetyltransferase in cucumber.

The molecular control of tendril development in angiosperms

“…Furthermore, A. thaliana AtGCN5 is involved in light‐activated expression of many genes (Li et al ., ). Cucumber CsGCN5 mutants, besides displaying the tendril‐less phenotype, display defects in development similar to A. thaliana AtGCN5 mutants, which suggests that CsGCN5 may play similar roles during cucumber development as in A. thaliana (Chen et al ., ). Hence, CsGCN5 might be involved in light signaling during tendril development in cucumber, being somehow associated with the skototropic behavior of tendrils in this plant.…”

“…In addition, Mizuno et al (2015) identified a serine residue in the DNA-binding region of the protein that may also have functional significance for tendril evolution in Cucurbitaceae and is unique to C. sativus, C. melo and Citrullus lanatus. Recently, tendril-less1 (td-1), another C. sativus tendril-less mutant has been described (Chen et al, 2017). Tendril-less1 phenotype is caused by a nonsynonymous single nucleotide polymorphism (SNP) in the first exon of the gene CsGCN5 (C. sativus GENERAL CONTROL NONDEREPRESSIBLE 5; Chen et al, 2017).…”

“…Recently, tendril-less1 (td-1), another C. sativus tendril-less mutant has been described (Chen et al, 2017). Tendril-less1 phenotype is caused by a nonsynonymous single nucleotide polymorphism (SNP) in the first exon of the gene CsGCN5 (C. sativus GENERAL CONTROL NONDEREPRESSIBLE 5; Chen et al, 2017).…”

“…CYC1 genes maintained their TEOSINTE BRANCHED1-like (TB1-like) role across different taxa, as they negatively regulate axillary bud outgrowth in monocots and eudicots (Dhaka et al, 2017). CsGCN5 is homologous to the A. thaliana AtGCN5 that encodes a histone acetyltransferase (Chen et al, 2017).…”

Diversification of the Histone Acetyltransferase GCN5 through Alternative Splicing in Brachypodium distachyon

“…The higher observed relative transcript abundance of all BdGCN5 variants in crown tissue, when compared to aerial tissues, suggests a putative role in meristem-dependent processes (Figures 2D–F ). This observation is not surprising as GCN5 is known to be involved in developmental mechanisms in other plant species (Bertrand et al, 2003 ; Vlachonasios et al, 2003 ; Cohen et al, 2009 ; Kornet and Scheres, 2009 ; Poulios and Vlachonasios, 2016 ; Chen et al, 2017 ). Following exposure to low temperatures, the apparent circadian increase in gene expression is repressed in all BdGCN5 alternative transcripts (Figure 3A ).…”