Departamento de Ciências Biológicas, Laboratório de Melhoramento de Plantas, Universidade Estadual de Santa Cruz (UESC), Rod. Jorge Amado, km 16, 45662-900, Ilhéus, Brasil.
Mol Biol Rep. 2022 Nov;49(11):10279-10292. doi: 10.1007/s11033-022-07520-z. Epub 2022 Sep 12.
This study on cultivars of melon (Cucumis melo L.) marketed in Brazil was conducted to obtain information to be used in breeding programs of this species. Little is known about the karyotype variability among C. melo L. cultivars targeted at the consumer market. The objective of the present study was to verify the karyotype variability in eight commercial melon cultivars used in the Brazilian market.
Slides were stained with 2% Giemsa and assembled with Neomount to perform chromosomal morphometry. GC-rich heterochromatin was observed by CMA/DAPI staining. 5 S rDNA, centromeric satellite DNA (SatDNA), and telomeric sites were visualized using fluorescence in situ hybridization. All images were captured on an Olympus BX41 microscope equipped with a 5 M Olympus DP25 digital camera and DP2-BSW software. The cultivars showed symmetrical karyotypes with significant differences in total chromosome length and average chromosome size. Heterochromatic CMA blocks were observed in terminal regions related to satellites (secondary constrictions), as well as in centromeric and pericentromeric regions. A single chromosomal pair of 5 S rDNA sites was observed in all cultivars, but at distinct locations. Centromeric satellite sequences, tested for the first time in melon, revealed only centromeric sites. Telomeric sites were observed in all the chromosomes of the cultivars.
Karyotype variation was observed in cultivars of melon, which were analyzed for chromosomal morphology and localization of GC-rich heterochromatin, as well centromeric SatDNA, rDNA, and telomeric chromosomal markers. Hence, these cultivars can be used in future breeding programs.
本研究对在巴西市场上销售的甜瓜（Cucumis melo L.）品种进行了研究，旨在为该物种的选育计划提供信息。目前对于面向消费者市场的甜瓜品种的核型变异知之甚少。本研究的目的是验证在巴西市场上使用的 8 个商业甜瓜品种的核型变异性。
使用 2% Giemsa 染色并使用 Neomount 组装以进行染色体形态测量。通过 CMA/DAPI 染色观察富含 GC 的异染色质。使用荧光原位杂交可视化 5S rDNA、着丝粒卫星 DNA（SatDNA）和端粒位点。所有图像均使用配备有 5M Olympus DP25 数字相机和 DP2-BSW 软件的 Olympus BX41 显微镜捕获。这些品种的核型具有对称性，总染色体长度和平均染色体大小存在显著差异。在与卫星（次级缢痕）相关的末端区域以及着丝粒和着丝粒周围区域观察到异染色质 CMA 块。在所有品种中都观察到单个 5S rDNA 位点的染色体对，但位置不同。首次在甜瓜中测试的着丝粒卫星序列仅显示着丝粒位点。在所有品种的染色体上都观察到端粒位点。
观察到了甜瓜品种的核型变异，对其进行了染色体形态和 GC 丰富异染色质以及着丝粒 SatDNA、rDNA 和端粒染色体标记的定位分析。因此，这些品种可以用于未来的选育计划。
