Table_3_Comparative Transcriptome Analysis Provides Insights Into Yellow Rind Formation and Preliminary Mapping of the Clyr (Yellow Rind) Gene in Watermelon.xls

As an important appearance trait, the rind color of watermelon fruit affects the commodity value and further determines consumption choices. In this study, a comparative transcriptome analysis was conducted to elucidate the genes and pathways involved in the formation of yellow rind fruit in watermelon using a yellow rind inbred line WT4 and a green rind inbred line WM102. A total of 2,362 differentially expressed genes (DEGs) between WT4 and WM102 at three different stages (0, 7, and 14 DAP) were identified and 9,770 DEGs were obtained by comparing the expression level at 7 DAP and 14 DAP with the former stages of WT4. The function enrichment of DEGs revealed a number of pathways and terms in biological processes, cellular components, and molecular functions that were related to plant pigment metabolism, suggesting that there may be a group of common core genes regulating rind color formation. In addition, next-generation sequencing aided bulked-segregant analysis (BSA-seq) of the yellow rind pool and green rind pool selected from an F2 population revealed that the yellow rind gene (Clyr) was mapped on the top end of chromosome 4. Based on the BSA-seq analysis result, Clyr was further confined to a region of 91.42 kb by linkage analysis using 1,106 F2 plants. These results will aid in identifying the key genes and pathways associated with yellow rind formation and elucidating the molecular mechanism of rind color formation in watermelon.

作为一项关键的外观性状，西瓜果实的果皮颜色不仅影响商品价值，更直接决定消费者的选购决策。本研究以黄果皮自交系WT4与绿果皮自交系WM102为实验材料，开展比较转录组分析，以解析调控西瓜黄果皮形成的相关基因及分子通路。研究共计在两个材料的三个不同发育阶段（0、7及14 DAP，即授粉后天数）中鉴定出2362个差异表达基因（differentially expressed genes, DEGs）；同时将WT4在7 DAP和14 DAP的基因表达水平与其更早发育阶段进行对比，共获得9770个差异表达基因。对差异表达基因进行功能富集分析后发现，其显著富集于植物色素代谢相关的生物学过程、细胞组分及分子功能等多个条目，提示可能存在一组共同的核心基因调控果皮颜色形成。此外，本研究利用从F₂群体中筛选得到的黄果皮池与绿果皮池，通过下一代测序结合集群分离分析（bulked-segregant analysis, BSA-seq），将控制黄果皮的基因Clyr定位在4号染色体的顶端区域。基于BSA-seq的分析结果，本研究进一步利用1106株F₂群体单株进行连锁分析，将Clyr基因精细定位至91.42 kb的区间内。上述研究结果将有助于挖掘与西瓜黄果皮形成相关的关键基因及通路，阐明西瓜果皮颜色形成的分子机制。