Fine Mapping of CsVYL, Conferring Virescent Leaf Through the Regulation of Chloroplast Development in Cucumber

Abstract

Leaf color mutants in higher plants are ideal materials for investigating the structure and function of photosynthetic system. In this study, we identified a cucumber vyl (virescent-yellow leaf) mutant in the mutant library, which exhibited reduced pigment contents and delayed chloroplast development process. F2 and BC1 populations were constructed from the cross between vyl mutant and cucumber inbred line ‘Hazerd’ to identify that the vyl trait is controlled by a simply recessive gene designated as CsVYL. The CsVYL gene was mapped to a 3.8 cM interval on chromosome 4 using these 80 F2 individuals and BSA (bulked segregation analysis) approach. Fine genetic map was conducted with 1542 F2 plants and narrowed down the vyl locus to an 86.3 kb genomic region, which contains a total of 11 genes. Sequence alignment between the wild type (WT) and vyl only identified one single nucleotide mutation (C→T) in the first exon of gene Csa4G637110, which encodes a DnaJ-like zinc finger protein. Gene Expression analysis confirmed the differences in transcription level of Csa4G637110 between wild type and mutant plants. Map-based cloning of the CsVYL gene could accelerate the study of chloroplast development and chlorophyll synthesis of cucumber.

Identification of two recessive etiolation genes (py1, py2) in pakchoi (Brassica rapa L. ssp. chinensis)

“…For most leaf color mutants, the traits are recessively inherited and controlled by a single nuclear gene. The F 2 populations are instinctively applied to map the target gene [5,41,58].…”

“…When the Chl content changes in plants, various leaf color mutant phenotypes result including chlorina, virescent, albino, yellow-green, and stay-green [2]. Leaf color mutants develop from the inhibition of genes regulating Chl biosynthesis and chloroplast development.Downregulation of these genes directly or indirectly influences Chl synthesis and degradation and produces the leaf color mutations [3][4][5]. Thus, leaf color mutants may be ideally suited for the elucidation of the mechanisms of photosynthesis, Chl biosynthesis, chloroplast development, and the expression and regulation of the genes associated with these processes [6][7][8][9].…”

Identification of two recessive etiolation genes (py1, py2) in pakchoi (Brassica rapa L. ssp. chinensis)

“…Relative to the reference genome, 154,863 and 157,022 SNPs were detected in the G-pool and Y-pool, respectively. Differential SNP loci were screened for ED 5 calculation and 412 target differential SNP loci were obtained between the pools according to the top 1% ED 5 threshold. Two distinct peaks were observed on chromosomes A07 and A09 ( Fig.…”

“…Leaf color mutants develop from the inhibition of genes regulating Chl biosynthesis and chloroplast development. Downregulation of these genes directly or indirectly influences Chl synthesis and degradation and produces the leaf color mutations [3][4][5]. Thus, leaf color mutants may be ideally suited for the elucidation of the mechanisms of photosynthesis, Chl biosynthesis, chloroplast development, and the expression and regulation of the genes associated with these processes [6][7][8][9].…”

“…Thus, leaf color mutants may be ideally suited for the elucidation of the mechanisms of photosynthesis, Chl biosynthesis, chloroplast development, and the expression and regulation of the genes associated with these processes [6][7][8][9]. Leaf color mutants have been characterized in Arabidopsis [10], rice [11,12], wheat [13], Brassica napus [14], Brassica oleracea [15], barley [16], kale [17], tobacco [18], soybean [19], cotton [20], and cucumber [5,21]. Much research has been invested in the analysis of the genetics, physiology, and molecular mechanisms of Chl biosynthesis and chloroplast development via leaf color mutants.…”