Fine Mapping and Functional Analysis of Major Regulatory Genes of Soluble Solids Content in Wax Gourd (Benincasa hispida)

Abstract

Soluble solids content (SSC) is an important quality trait of wax gourd, but reports about its regulatory genes are scarce. In this study, the SSC regulatory gene BhSSC2.1 in wax gourd was mined via quantitative trait locus (QTL) mapping based on high-density genetic mapping containing 12 linkage groups (LG) and bulked segregant analysis (BSA)-seq. QTL mapping and BSA-seq revealed for the first time that the SSC QTL (107.658–108.176 cM) of wax gourd was on Chr2 (LG2). The interpretable phenotypic variation rate and maximum LOD were 16.033% and 6.454, respectively. The QTL interval contained 13 genes. Real-time fluorescence quantitative expression analysis, functional annotation, and sequence analysis suggested that Bch02G016960, named BhSSC2.1, was a candidate regulatory gene of the SSC in wax gourd. Functional annotation of this gene showed that it codes for a NADP-dependent malic enzyme. According to BhSSC2.1 sequence variation, an InDel marker was developed for molecular marker-assisted breeding of wax gourd. This study will lay the foundation for future studies regarding breeding and understanding genetic mechanisms of wax gourd.

Development and Application of InDel Markers Linked to Fruit-Shape and Peel-Colour Genes in Wax Gourd

“…The InDel markers developed in this study can reduce costs and improve efficiency while ensuring high detection accuracy. With the rapid development of high-throughput sequencing technology and reduction in sequencing costs, the use of resequencing data to fine map genes and develop InDel markers closely linked to genes has been extended to several crops, including cucumbers [ 26 ], tomatoes [ 27 ], Brassica napus [ 28 ], melons [ 29 ], and watermelons [ 30 ]. Genes that regulate fruit shape and peel colour have been identified in many crops, and gene-linked InDel markers related to fruit shape have been developed in watermelons [ 31 ], cucumbers [ 32 ], and melons [ 33 ]; those associated with peel colour have been developed in peppers [ 34 ], eggplants [ 35 ], tomatoes [ 36 ], cucumbers [ 37 ], chieh qua [ 3 ], melons [ 38 ], and watermelons [ 39 ].…”

Fine mapping of the major gene BhHLS1 controlling seed size in wax gourd (Benincasa hispida)

“…Progress has been made in developing and applying molecular markers of fruit-related traits in wax gourd (Cheng et al, 2021;Ma et al, 2021;Huang et al, 2022;Wu et al, 2022b). In this study, a CAPS marker based on an exon G/T mutation in BhHLS1 was developed for the testing of genotypic and phenotypic concordance using 60 extreme materials with an accuracy of 96.7% (Figure 5B) and can thus be used for future marker-assisted breeding.…”