Major QTL Mapping and Candidate Gene Analysis of Branching Number Habits in <i>Cucumis melo</i>
Branching number (BN) is a crucial architectural trait in <i>Cucumis melo.</i> Because of its multiple branch habits, much more labour costs are needed in melon production. However, the genetic mechanism of branching numbers in melon is not clear. Here, a genetic population from multiple...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Agronomy |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4395/14/12/3012 |
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| Summary: | Branching number (BN) is a crucial architectural trait in <i>Cucumis melo.</i> Because of its multiple branch habits, much more labour costs are needed in melon production. However, the genetic mechanism of branching numbers in melon is not clear. Here, a genetic population from multiple branching material S8 (only two branching number in the first node) as the female line and S7 (multiple branching numbers in each node; more than nine branch numbers) as the male parent is used to make a cross F<sub>2:3</sub> generation. By performing QTL mapping based on bulked segregate analysis (BSA) after two years, a candidate QTL region of the BN was located on chromosome 3. For further QTL mapping, a genetic linkage map, which contained 16 SSR markers with a total length of 2.27 Mb, was constructed. One major QTL locus <i>bnDQ-2022-3.1</i> was detected between <i>CmSSR9556</i> and <i>CmSSR9580</i>, with a LOD threshold of 11.37 and a contribution rate of 49.11% in the spring of 2022 in Daqing City. Then, a consistent QTL <i>bnSY-2022-3.1</i> was also investigated in Sanya, Hainan Province, in the autumn of 2022, with a LOD threshold of 10.85 and a contribution rate of 45.01%. Nine genes were investigated within the interval of the candidate region located in chromosome 3 between 22,723,436 and 22,807,889 of the melon’s physical position within the 85.45 kb length region. Gene expression analysis showed significant differences between <i>MELO3C019872.2.1</i>, <i>MELO3C030060.2.1</i>, and <i>MELO3C019871.2.1</i> in different development stages. Gene sequence different analysis revealed a “C”-to-“T” mutation in the 1280 bp site of <i>MELO3C030060.2.1</i> in parental lines. Heterologous transformation of <i>MELO3C030060.2.1</i> into cucumber revealed that overexpression of <i>MELO3C030060.2.1</i> resulted in more and denser branches in cucumber plants, and the growth rate of lateral branches was significantly faster than that of the wild type. Transferring to antisense of <i>MELO3C030060.2.1</i> had the opposite effect. To sum up, <i>MELO3C030060.2.1</i> is related to melon branching initial habits. This study could provide a new insight into melon branching habits and provide a theoretical base for melon breeding. |
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| ISSN: | 2073-4395 |