Xu Shuo, Wang Yaru, Yang Songlin, Fan Shanshan, Shi Kexin, Wang Fang, An Menghang, Qi Yu, Wang Mingqi, Feng Min, Li Zhifang, Liu Xingwang, Ren Huazhong
Engineering Research Center of Breeding and Propagation of Horticultural Crops, Ministry on Education, College of Horticulture, China Agricultural University, Beijing 100193, China.
Sanya Institute of China Agricultural University, Sanya Hainan 572000, China.
Hortic Res. 2024 Jun 14;11(8):uhae163. doi: 10.1093/hr/uhae163. eCollection 2024 Aug.
Cucumber ( L.) is a widely cultivated crop with rich germplasm resources, holding significant nutritional value. It also serves as an important model for studying epidermal cell fate and sex determination. Cucumbers are covered with multicellular and unbranched trichomes, including a specific type called spines found on the surface of the fruit. The presence and density of these fruit spines determine the visual quality of cucumber fruits. However, the key regulatory genes and mechanisms underlying cucumber fruit spine development remain poorly understood. In this study, we identified a WUSCHEL-related homeobox (WOX) family gene , which functioned as a typical transcriptional repressor and played a negative role in fruit spine development. Spatial-temporal expression analysis revealed that exhibited a relatively high expression level in the cucumber female floral organs, particularly in the fruit exocarp. Knockout of using CRISPR/Cas9 resulted in a significant 2-to-3-fold increase in the diameter of fruit spines base, while overexpression led to a 17% decrease in the diameter compared to the wild-type. A SQUAMOSA PROMOTER BINDING PROTEIN-LIKE transcription factor CsSPL15 could directly bind and activate the expression of , thereby suppressing the expression of downstream auxin-related genes, such as . Additionally, the RING-finger type E3 ubiquitin ligase CsMIEL1-like interacted with the HD domain of CsWOX3, which might result in the ubiquitination and subsequent alteration in protein stability of CsWOX3. Collectively, our study uncovered a WOX transcription factor and elucidated its expression pattern and biological function. This discovery enhances our comprehension of the molecular mechanism governing cucumber fruit spine morphogenesis.
黄瓜（Cucumis sativus L.）是一种广泛种植的作物，拥有丰富的种质资源，具有重要的营养价值。它也是研究表皮细胞命运和性别决定的重要模型。黄瓜表面覆盖着多细胞且无分支的毛状体，包括在果实表面发现的一种特定类型的刺。这些果实刺的存在和密度决定了黄瓜果实的外观品质。然而，黄瓜果实刺发育的关键调控基因和机制仍知之甚少。在本研究中，我们鉴定出一个与WUSCHEL相关的同源异型框（WOX）家族基因，它作为典型的转录抑制因子，在果实刺发育中起负向作用。时空表达分析表明，该基因在黄瓜雌性花器官中表达水平相对较高，尤其是在果实外果皮中。利用CRISPR/Cas9敲除该基因导致果实刺基部直径显著增加2至3倍，而过表达则导致直径相比野生型降低17%。一个类似SQUAMOSA启动子结合蛋白的转录因子CsSPL15可以直接结合并激活该基因的表达，从而抑制下游生长素相关基因如[具体基因名称未给出]的表达。此外，RING指型E3泛素连接酶CsMIEL1-like与CsWOX3的HD结构域相互作用，这可能导致CsWOX3的泛素化及随后蛋白质稳定性的改变。总体而言，我们的研究发现了一个WOX转录因子，并阐明了其表达模式和生物学功能。这一发现增进了我们对黄瓜果实刺形态发生分子机制的理解。
