AUTHOR=Wu Xiaohua , Wu Xinyi , Wang Ying , Wang Baogen , Lu Zhongfu , Xu Pei , Li Guojing 

TITLE=Molecular Genetic Mapping of Two Complementary Genes Underpinning Fruit Bitterness in the Bottle Gourd (Lagenaria siceraria [Mol.] Standl.)

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.01493

DOI=10.3389/fpls.2019.01493

ISSN=1664-462X

ABSTRACT=<p>Fruit bitterness is a serious problem threatening the bottle gourd (<italic>Lagenaria siceraria</italic> [Mol.] Standl.) industry worldwide. Previous genetic studies indicated that fruit bitterness in the bottle gourd was controlled by a pair of complementary genes. In this study, based on two non-bitter landraces “Hangzhou Gourd” and “Puxian Gourd,” each of which carries a single bitterness gene, and their derived segregation populations, we mapped the complementary genes causing fruit bitterness. Quantitative trait locus (QTL) scanning based on an F<sub>2</sub> population detected two QTLs, which was <italic>QBt.1</italic> locating in a 17.62-cM interval on linkage group (LG)2 corresponding to a 1.6-Mb region on chromosome 6, and <italic>QBt.2</italic> mapped to a 8.44-cM interval on LG9 corresponding to a 1.9-Mb region on chromosome 7. An advanced bulked segregant analysis (A-BSA) well validated the QTL mapping results. Sequence-based comparative analysis showed no syntenic relationship between <italic>QBt.1/QBt.2</italic> and the known bitterness genes in cucumber, melon, and watermelon, suggesting that causal genes underlying <italic>QBt.1</italic> and <italic>QBt.2</italic> were not direct orthologs of the reported cucurbit bitterness genes. Our results shed light on the molecular genetic mechanisms underlying fruit bitterness in the bottle gourd and is useful to guide breeders to properly select parental lines to avoid the occurrence of bitter fruits in breeding programs.</p>