DataSheet_1_Transcription Factor CsWIN1 Regulates Pericarp Wax Biosynthesis in Cucumber Grafted on Pumpkin.xlsx

Pericarp wax of cucumber is an important economic trait, determining sales and marketing. Grafting of cucumber onto pumpkin rootstock (Cucurbita moschata) is an effective way to produce glossy cucumber fruits. However, the molecular regulation mechanism of this phenomenon remains largely unknown. In the present study, transcriptome analyses, genome-wide DNA methylation sequencing, and wax metabolite analysis were performed on the pericarp of self-rooted versus grafted cucumber. We identified the AP2/ERF-type transcription factor CsWIN1 as methylated and significantly upregulated in grafted cucumber compared to self-rooted cucumber. The increased expression of CsWIN1 was also positively correlated with several key wax biosynthesis genes, including CsCER1, CsCER1-1, CsCER4, CsKCS1, and the wax transporter gene CsABC. The transcriptome expression level of these genes was validated through qRT-PCR profiles. Furthermore, wax metabolite analysis showed that more wax ester (C20 fatty acid composition), but fewer alkanes (C29 and C31) were deposited in grafted cucumber pericarp. The higher expression of CsWIN1 and wax biosynthesis genes was reflected in the glossier appearance of grafted pericarp, possibly the result of higher wax ester content and higher integration of small trichomes in the pericarp. This study demonstrates that grafting can affect the content and composition of pericarp wax in cucumber grafted on pumpkin, and a unique regulation model of CsWIN1 for wax biosynthesis may exist in cucumber.

黄瓜果实的果皮蜡层是其重要的经济性状，直接影响其销售与市场营销。将黄瓜嫁接于南瓜（Cucurbita moschata）砧木之上，是一种培育光亮黄瓜果实的高效方法。然而，此现象的分子调控机制至今尚处于未知状态。本研究中，我们对自根与嫁接黄瓜的果皮进行了转录组分析、全基因组DNA甲基化测序以及蜡代谢物分析。我们发现，与自根黄瓜相比，嫁接黄瓜中甲基化的AP2/ERF型转录因子CsWIN1表达显著上调。CsWIN1表达的增加与多个关键的蜡生物合成基因（包括CsCER1、CsCER1-1、CsCER4、CsKCS1以及蜡转运基因CsABC）呈正相关。通过qRT-PCR分析验证了这些基因的转录组表达水平。此外，蜡代谢物分析显示，嫁接黄瓜果皮中沉积的蜡酯（C20脂肪酸组成）更多，而烷烃（C29和C31）则较少。CsWIN1和蜡生物合成基因的高表达与嫁接果皮的更光泽外观相关，这可能归因于蜡酯含量更高以及果皮中小毛茸的更高集成度。本研究揭示了嫁接可以影响南瓜砧木上嫁接黄瓜果皮的蜡含量和组成，并可能在黄瓜中存在一种独特的CsWIN1调控蜡生物合成的模型。