Map-based cloning of the APRR2 gene controlling green stigma in bitter gourd (Momordica charantia)

Jinyi Zhan; Jian Zhong; Jiaowen Cheng; Yuhui Wang; Kailin Hu

doi:10.3389/fpls.2023.1128926

Map-based cloning of the APRR2 gene controlling green stigma in bitter gourd (Momordica charantia)

Front Plant Sci. 2023 May 10:14:1128926. doi: 10.3389/fpls.2023.1128926. eCollection 2023.

Authors

Jinyi Zhan^{1

2}, Jian Zhong¹, Jiaowen Cheng¹, Yuhui Wang², Kailin Hu¹

Affiliations

¹ Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs/Guangdong Vegetables Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China.
² State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, College of Horticulture, Nanjing Agricultural University, Nanjing, China.

Abstract

Bitter gourd is an economically important vegetable and medicinal crop distinguished by its bitter fruits. Its stigma color is widely used to assess the distinctiveness, uniformity, and stability of bitter gourd varieties. However, limited researches have been dedicated to genetic basis of its stigma color. In this study, we employed bulked segregant analysis (BSA) sequencing to identify a single dominant locus McSTC1 located on pseudochromosome 6 through genetic mapping of an F₂ population (n =241) derived from the cross between green and yellow stigma parental lines. An F₂-derived F₃ segregation population (n = 847) was further adopted for fine mapping, which delimited the McSTC1 locus to a 13.87 kb region containing one predicted gene McAPRR2 (Mc06g1638), a homolog of the Arabidopsis two-component response regulator-like gene AtAPRR2. Sequence alignment analysis of McAPRR2 revealed that a 15 bp insertion at exon 9 results in a truncated GLK domain of its encoded protein, which existed in 19 bitter gourd varieties with yellow stigma. A genome-wide synteny search of the bitter gourd McAPRR2 genes in Cucurbitaceae family revealed its close relationship with other cucurbits APRR2 genes that are corresponding to white or light green fruit skin. Our findings provide insights into the molecular marker-assisted breeding of bitter gourd stigma color and the mechanism of gene regulation for stigma color.

Keywords: BSA-seq; McAPRR2; bitter gourd; fine mapping; stigma color.

Grants and funding

This study was supported by a grant from the Key Project of Basic and Applied Research for University in Guangdong Province (2018KZDXM016), the Science and Technology Planning Project of Guangdong Province (2018B020202007), the Guangzhou Science and Technology Plan Projects (202002020086, 202102020800, and 202206010170), and the Science and Technology Plan Projects of Guangdong Province (2019A050520002). YW was supported by the Nanjing Agricultural University Startup Fund (130804131).