AUTHOR=Peng Jiazhu , Gao Yin , Qiao Yanchun , Wang Guoping 

TITLE=A point mutation in the zinc-finger transcription factor CqLOL1 controls the green flesh color in chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How)

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1388115

DOI=10.3389/fpls.2024.1388115

ISSN=1664-462X

ABSTRACT=<sec><title>Introduction</title><p>Flesh color is an essential trait in chieh-qua (<italic>Benincasa hispida</italic> Cogn. var. <italic>Chieh-qua</italic> How); however, the inheritance and molecular basis of green flesh trait remain unclear.</p></sec><sec><title>Methods</title><p>In the present study, two F<sub>2</sub> populations, derived from 1742 (white flesh) × FJ3211 (green flesh) and J16 (white flesh) × FJ5 (green flesh), were used to identify the green flesh (<italic>Cqgf</italic>) locus.</p></sec><sec><title>Results</title><p>Genetic analysis revealed that the presence of green flesh was a quantitative trait that closely followed a normal distribution. Combining the results from QTL mapping and BSA-seq analysis, the <italic>Cqgf</italic> locus was preliminarily determined to be located on chromosome 05 and was narrowed down to a 2.55-Mb interval by linkage analysis. A large J16 × FJ5 F<sub>2</sub> population comprising 3,180 individuals was subsequently used to screen the recombinants, and the <italic>Cqgf</italic> locus was fine-mapped to a region of 329.70 kb that harbors six genes. One of the candidate genes, <italic>Bch05G003700</italic>, the zinc-finger transcription factor LOL1 (lsd one like 1 protein; <italic>CqLOL1</italic>), was the strongest candidate gene for the <italic>Cqgf</italic> locus according to sequence variation and expression analysis. Additionally, a point mutation (A &gt; C) in <italic>CqLOL1</italic> resulted in the substitution of threonine (T) with proline (P) in the amino acid sequence, showing a complete relationship linked with flesh color in a panel of 45 germplasms.</p></sec><sec><title>Discussion</title><p>The study suggests that <italic>CqLOL1</italic> promotes the accumulation of chlorophyll content in chieh-qua and lead to green flesh. Our findings establish a theoretical and technical foundation for breeding different flesh color lines and elucidating the underlying mechanisms of flesh color in chieh-qua.</p></sec>