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Title: Fine mapping of short hypocotyl locus in semi-wild Xishuangbanna cucumber

item Weng, Yiqun
item BO, KAILING - University Of Wisconsin
item YANG, LUMING - University Of Wisconsin
item Simon, Philipp
item CHEN, JINFENG - Nanjing Agricultural University

Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/10/2015
Publication Date: 1/12/2015
Citation: Weng, Y., Bo, K., Yang, L., Simon, P.W., Chen, J. 2015. Fine mapping of short hypocotyl locus in semi-wild Xishuangbanna cucumber [abstract]. Plant and Animal Genome Conference. Paper No. P0932.

Interpretive Summary:

Technical Abstract: In cucumber, hypocotyl length is a useful trait in establishing strong seedlings before transplanting or grafting. The semi-wild Xishuangbanna cucumber (XIS) exhibits very short hypocotyl as compared with most cultivated cucumbers. In this study, we investigated the inheritance of short hypocotyl with 124 recombinant inbred lines (RILs) derived from a cross between a cultivated cucumber inbred line with normal hypocotyl length and the XIS cucumber SWCC8. We confirmed that a single recessive gene, sh, controlled the short hypocotyl. Initial framework mapping with microsatellite markers located sh locus in cucumber chromosome 3. Fine mapping was conducted with draft genome scaffold-assisted chromosome walking and stepwise increase of mapping population sizes, which allowed delimiting the sh locus to a 63 kb genomic DNA region in a mapping population of 664 F2 plants. Annotation of this region identified four putative genes including a Arabidopsis thaliana RAD5 DNA repair gene. Sequence alignment of the RAD5 homologs between the two parents revealed a single nucleotide polymorphism (SNP) in the sixth exon of this candidate gene. A dCAPS maker based on this SNP was co-segregating with the hypocotyl length in both RIL and F2 populations. This RAD5 gene seems to be the best candidate gene for the sh locus conditioning the short hypocotyl of the XIS cucumber.