Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs/Northeast Agricultural University, Harbin, 150030, China.
College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, China.
Theor Appl Genet. 2024 Jun 22;137(7):167. doi: 10.1007/s00122-024-04676-z.
A large fragment deletion of CpAPRR2, encoding a two-component response regulator-like protein, which influences immature white rind color formation in zucchini (Cucurbita pepo). Fruit rind color is an important agronomic trait that affects commodity quality and consumer choice in zucchini (Cucurbita pepo). However, the molecular mechanism controlling rind color is unclear. We characterized two zucchini inbred lines: '19' (dark green rind) and '113' (white rind). Genetic analysis revealed white immature fruit rind color to be controlled by a dominant locus (CpW). Combining bulked segregant analysis sequencing (BSA-seq) and Kompetitive Allele-Specific PCR (KASP) markers, we mapped the CpW locus to a 100.4 kb region on chromosome 5 and then narrow down the candidate region to 37.5 kb using linkage analysis of 532 BC and 1613 F individuals, including 6 coding genes. Among them, Cp4.1LG05g02070 (CpAPRR2), encoding a two-component response regulator-like protein, was regarded to be a promising candidate gene. The expression level of CpAPRR2 in dark green rind was significantly higher than that in white rind and was induced by light. A deletion of 2227 bp at the 5' end of CpAPRR2 in '113' might explain the white phenotype. Further analysis of allelic diversity in zucchini germplasm resources revealed rind color to be associated with the deletion of CpAPRR2. Subcellular localization analysis indicated that CpAPRR2 was a nuclear protein. Transcriptome analysis using near-isogenic lines with dark green (DG) and white (W) rind indicated that genes involved in photosynthesis and porphyrin metabolism pathways were enriched in DG compared with W. Additionally, chlorophyll synthesis-related genes were upregulated in DG. These results identify mechanisms of zucchini rind color and provide genetic resources for breeding.
APRR2 基因大片段缺失影响西葫芦未成熟白皮颜色形成，该基因为二组分调控蛋白样基因。果皮颜色是西葫芦的一个重要农艺性状，影响其商品品质和消费者选择。然而，调控果皮颜色的分子机制尚不清楚。本研究对 2 个西葫芦自交系‘19’（深绿果皮）和‘113’（白皮）进行了研究。遗传分析表明，白皮未成熟果实颜色受显性基因位点（CpW）控制。通过结合 bulked segregant analysis sequencing (BSA-seq) 和 Kompetitive Allele-Specific PCR (KASP) 标记，我们将 CpW 位点定位到第 5 号染色体上的 100.4 kb 区域，然后通过包括 6 个编码基因的 532 个 BC1 和 1613 个 F2 个体的连锁分析将候选区域缩小到 37.5 kb。其中，编码二组分调控蛋白样蛋白的 Cp4.1LG05g02070（CpAPRR2）被认为是一个有希望的候选基因。深绿果皮中 CpAPRR2 的表达水平明显高于白皮，且受光照诱导。‘113’中 CpAPRR2 的 5'端缺失 2227 bp 可能解释了其白皮表型。对西葫芦种质资源中等位基因多样性的进一步分析表明，果皮颜色与 CpAPRR2 的缺失有关。利用深绿（DG）和白皮（W）近等基因系的转录组分析表明，与 W 相比，DG 中与光合作用和卟啉代谢途径相关的基因富集。此外，DG 中叶绿素合成相关基因上调。这些结果为西葫芦果皮颜色形成的机制提供了研究依据，为其遗传改良提供了遗传资源。
