Genetic mapping and molecular characterization of the delayed green gene dg in watermelon (Citrullus lanatus)

Abstract

Leaf color mutants are common in higher plants that can be used as markers in crop breeding and are important tools in understanding regulatory mechanisms of chlorophyll biosynthesis and chloroplast development. Genetic analysis was performed by evaluating F1, F2 and BC1 populations derived from two parental lines (Charleston gray with green leaf color and Houlv with delayed green leaf color), suggesting that a single recessive gene controls the delayed green leaf color. In this study, the delayed green mutant showed a conditional pale green leaf color at the early leaf development but turned to green as the leaf development progressed. Delayed green leaf plants showed reduced pigment content, photosynthetic, chlorophyll fluorescence parameters, and impaired chloroplast development compared with green leaf plants. The delayed green (dg) locus was mapped to 7.48 Mb on chromosome 3 through bulk segregant analysis approach, and the gene controlling delayed green leaf color was narrowed to 53.54 kb between SNP130 and SNP135 markers containing three candidate genes. Sequence alignment of the three genes indicated that there was a single SNP mutation (G/A) in the coding region of ClCG03G010030 in the Houlv parent, which causes an amino acid change from Arginine to Lysine. The ClCG03G010030 gene encoded FtsH extracellular protease protein family is involved in early delayed green leaf development. The expression level of ClCG03G010030 was significantly reduced in delayed green leaf plants than in green leaf plants. These results indicated that the ClCG03G010030 might control watermelon green leaf color and the single SNP variation in ClCG03G010030 may result in early delayed green leaf color development during evolutionary process.

Natural Allelic Variations of Bch10G006400 Controlling Seed Size in Chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How)

“…BSA-seq analysis of the F 2 population was then used to map the late green locus of watermelon to 7.48 Mb on chromosome 3, after which a large number of CAPS markers were subsequently developed to screen recombinant plants in the F 2 population. Finally, three candidate genes controlling delayed green leaf color were mapped within a 53.54 Kb region between the SNP130 and SNP135 markers [27]. Analysis of F 2 and BC 1 plants by BSA-seq revealed that the skin color gene of wax gourd was located on chr05; a large number of F 2 plants were screened, after which the number of genes was reduced to 179 Kb, and the gene candidate Bch05G003950 was identified [28].…”

Ecophysiological studies of Citrullus colocynthis in response to spatial and seasonal changes in Wadi Al-Akhder, Tabuk Region, Saudi Arabia

“…Therefore, water scarcity decreased chlorophyll, carotenoids, and the ChA/B ratio of C. colocynthis (Bikdeloo et al 2021). Environmental influences impact the watermelon (C. lanatus) photosynthetic system and pigment production (Gebremeskel et al 2023). Under the sites x seasons interactions, the downstream with winter season significantly increased contents of ChA, ChB, and ChT, while, ChA/B, carotenoids and total pigment contents significantly increased upstream with the summer season, as compared to the values of the other interactions.…”