Construction of a high-density genetic map for yardlong bean and identification of ANT1 as a regulator of anthocyanin biosynthesis

Abstract

Because its long, tender pods supply essential proteins, vitamins, and fibers to humans, yardlong bean (Vigna unguiculata ssp. sesquipedalis) is a commonly consumed vegetable, especially in Southeast Asia. To provide insights into the genetic bases of key agricultural traits in yardlong bean, we here created a high-density bin-map with 2084 bin markers using 514 227 SNPs from a recombinant-inbred line (RIL) population. Quantitative trait loci (QTL) mapping was carried out to identify loci associated with anthocyanin content (ANT), vitamin E content (VE), total soluble protein content (TSP), pod length (PL), hundred-seed weight (HSW), seed length and width (SL and SW, respectively), and seed coat color (SCC). In total, 20 related QTLs were isolated, explaining 7.58-56.03% of the phenotypic variation. Of these, five major QTLs (qANT5, qTSP11, qVE7, qPL3, and qSCC9) were detected in 2020, 2021, and the combined environment, explaining 11.96-56.03% of the phenotypic variation. VuANT1 was identified as a causal gene for the QTL qANT5, which regulated anthocyanin content; VuANT1 was highly expressed in immature purple pods but barely detectable in white pods. VuANT1 overexpression in tobacco leaves and yardlong bean hairy roots resulted in purple coloration as a result of anthocyanin accumulation. These findings suggested that VuANT1 was a key regulator of anthocyanin accumulation in yardlong bean. Our results lay a firm foundation for target agricultural trait improvement and clarification of the genetic mechanisms underlying agricultural traits in yardlong bean.

Acknowledgements

This work was supported by the open competition project of seed industry revitalization of Jiangsu Province (JBGS[2021]063), Agriculture Research System of China (CARS–08–G15) and the cooperation program of IUR for Nanjing Agricultural Science & Technology (2023RHCXY Lvhe03).

Author contributions

H.Z., W.Z., and H.C participated in the conception and design of the experiment; H.Z. and W.Z. performed the experiments; W.Z and S.M conducted the phenotypic analysis and wrote the paper; and L.H., X.L., W.C., W.Y., and X.C. revised the manuscript. All authors have read and approved the final version of the manuscript.

Data availability

The data supporting the findings of this work are available within the paper and its supplementary information files. The datasets generated and analysed during this study are available from the corresponding author upon request.

Conflict of interest statement

The authors declare no competing interests.

Supplementary data

Supplementary data is available at Horticulture Research online.

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