Genetic mapping and development of molecular markers for a candidate gene locus controlling rind color in watermelon
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ClCG08G017810 (ClCGMenG) encoding a 2-phytyl-1,4-beta-naphthoquinone methyltransferase protein is associated with formation of dark green versus light green rind color in watermelon.
Rind color is an important agronomic trait in watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai], but the underlying molecular mechanism for this trait is not fully known. In the present study, we identified a single locus on chromosome 8 accounting for watermelon rind color (dark green vs. light green). Genetic analysis of F1, F2, and BC1 populations derived from two parental lines (9904 with dark green rind and Handel with light green rind) revealed that the watermelon rind color (dark green vs. light green) is controlled by a single locus, and dark green is dominant to light green rind. Initial mapping revealed a region of interest spanning 2.07 Mb on chromosome 8. Genetic mapping with CAPS and SNP markers narrowed down the candidate region to 31.4 kb. Gene annotation of the corresponding region in the reference genome revealed the ClCG08G017810 gene sequence encoding the 2-phytyl-1,4-beta-naphthoquinone methyltransferase protein. The sequence alignment of the candidate gene with the two parental lines suggested a nonsynonymous SNP mutation in the coding region of ClCG08G017810, converting an arginine (R) to glycine (G). The SNP might be associated with rind color of 103 watermelon germplasm lines investigated in this study. The qRT-PCR analysis revealed higher expression of ClCG08G017810 in dark green rind than in light green rind. Therefore, ClCG08G017810 is a candidate gene associated with watermelon rind color. The present study facilitates marker-assisted selection useful for the development of cultivars with desirable rind color.
This research was supported by National Key R&D Program of China (2018YFD0100704), the Agricultural Science and Technology Innovation Program (CAAS-ASTIP-2018-ZFRI), the China Agriculture Research System (CARS-25-03), the National Nature Science Foundation of China (31672178 and 31471893) and Central Public-interest Scientific Institution Basal Research Fund (Nos. 1616032017209 and 1610192016209).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
The experiments in this study comply with the current laws of China.
- Arnon DI (1949) Copper enzymes in isolated chloroplasts. Polyphenoloxidase in Beta vulgaris. Plant Physiol 24:1Google Scholar
- Barham WA (1956) study of the Royal Golden watermelon with emphasis on the inheritance of the chlorotic condition characteristic of this variety. In: Proceedings of the Society for Horticultural Science, pp 487–489Google Scholar
- Churchill GA, Doerge RW (1994) Empirical threshold values for quantitative trait mapping. Genetics 138:963–971Google Scholar
- Levi A et al (2011) Sequencing the genome of the heirloom watermelon cultivar Charleston Gray. In: XX plant and animal genome conference, San Diego, p P047Google Scholar
- Lohmann A, Schottler MA, Brehelin C, Kessler F, Bock R, Cahoon EB, Dormann P (2006) Deficiency in phylloquinone (vitamin K1) methylation affects prenyl quinone distribution, photosystem I abundance, and anthocyanin accumulation in the Arabidopsis AtmenG mutant. J Biol Chem 281:40461–40472. https://doi.org/10.1074/jbc.M609412200 CrossRefGoogle Scholar
- Shimada H, Ohno R, Shibata M, Ikegami I, Onai K, Ma Ohto, Ki Takamiya (2005) Inactivation and deficiency of core proteins of photosystems I and II caused by genetical phylloquinone and plastoquinone deficiency but retained lamellar structure in a T-DNA mutant of Arabidopsis. Plant J 41:627–637CrossRefGoogle Scholar
- van Oostende C, Widhalm JR, Furt F, Ducluzeau A-L, Basset GJ (2011) Vitamin K1 (Phylloquinone). In: Biosynthesis of vitamins in plants part B. Advances in Botanical Research, pp 229–261. https://doi.org/10.1016/b978-0-12-385853-5.00001-5
- Weetman LM (1937) Inheritance and correlation of shape size, and color in the watermelon. Iowa Agric Exp Stn Res Bull 228:222–256Google Scholar
- Wu S et al (2019) Genome of ‘Charleston Gray’, the principal American watermelon cultivar, and genetic characterization of 1,365 accessions in the US National Plant Germplasm System watermelon collection. Plant Biotechnol J 1–13Google Scholar
- Xiao-lei S, Bing W, San-jun G, Zhi-feng W (2003) Correlation of immature skin color and pigments in cucumber. Acta Hortic Sin 6:024Google Scholar
- Yang H-B, Park S, Park Y, Lee GP, Kang S-C, Kim YK (2015) Linkage analysis of the three loci determining rind color and stripe pattern in watermelon. Hortic Sci Technol Park 33:559–565Google Scholar