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Journal of Integrative Agriculture
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Functional analysis of CsAGL6 in flower development and pigmentation in cucumber (Cucumis sativus L.)

Li Qin1, 3 *, Zheyuan Liu1, 3*, Shuai Li1, 2, 4, Guanghua Cai1, 2, Jie Wang1, Xueyong Yang1, Jinjing Sun1#

1State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China

2Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518124,.China

3National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences, Sanya 572024, China

4Shandong Key Laboratory of Bulk Open-field Vegetable Breeding, Ministry of Agriculture and Rural Affairs Key Laboratory of Huang Huai Protected Horticulture Engineering, Institute of Vegetables, Shandong Academy of Agricultural Sciences, Jinan 250100, China

 Highlights 

1. CsAGL6 participates in sepal and petal development by regulating CAL and SEP4 in cucumber.

2. CsAGL6 affects petal pigmentation by modulating genes involved in chlorophyll biosynthesis and chloroplast development in cucumber.

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摘要  

黄瓜(Cucumis sativus L.)作为全球重要的蔬菜作物,其产量和品质与花发育密切相关。AGAMOUS-LIKE 6(AGL6)作为古老的MADS-box转录因子家族成员,在花发育过程中具有重要调控作用,但其在黄瓜中的同源基因功能尚未明确。本研究证实CsAGL6主要在花器官中表达,在花发育早期各花器官原基中均呈现高表达水平。在花发育的各个时期,Csagl6突变体的花瓣颜色都较野生型更绿,花瓣总叶绿素含量显著增加;同时Csagl6突变体表现出花瓣形态异常(包括大小和形态改变)及偶尔的萼片增大且叶片化表型。分子机制分析表明,Csagl6突变体中A类基因CAULIFLOWER (CAL)和E类基因SEPALLATA 4 (SEP4)显著下调,而叶绿素合成基因Early Light-Induced Protein 1 (ELIP1)及数个定位于叶绿体的应激反应相关基因显著上调。本研究为解析CsAGL6调控黄瓜萼片和花瓣发育的分子机制提供了新依据,并为理解黄瓜属植物花色素形成及器官形态建成的遗传调控提供了新思路。



Abstract  

Cucumber (Cucumis sativus L.) is a major vegetable crop worldwide, and its yield and quality are closely linked to flower development. AGAMOUS-LIKE 6 (AGL6), a member of the ancient MADS-box transcription factor family, plays a crucial role in flower development. However, the specific functions of its homolog in cucumber remain poorly understood. In this study, we demonstrate that CsAGL6 is predominantly expressed in flowers, with high expression levels observed in all floral organ primordia during the early stages of floral development. The petals of Csagl6 mutants exhibit a greener color compared to wild-type plants, along with a significant increase in total chlorophyll content. Additionally, the mutants show abnormal petal morphology, including changes in size and shape, as well as enlarged sepals resembling leaves occasionally. Molecular analysis reveals that the A-class gene CAULIFLOWER (CAL) and the E-class gene SEPALLATA 4 (SEP4) are significantly downregulated in the mutants, while the chlorophyll synthesis gene Early Light-Induced Protein 1 (ELIP1) and several stress-related genes in the chloroplasts are dramatically upregulated. Our findings provide novel insights into the functional role of CsAGL6 in regulating sepal and petal development, and offer a potential avenue for understanding the genetic control of flower pigmentation and organ morphology in Cucumis species.

Keywords:  cucumber       flower development              CsAGL6                
Online: 13 November 2025  
Fund: 

This work was supported by the National Natural Science Foundation of China (31820103012), the earmarked fund for China Agriculture Research System (CARS-28), and the Earmarked Fund for Jiangsu Agricultural Industry Technology System (JATS[2022]454).

Cite this article: 

Li Qin, Zheyuan Liu, Shuai Li, Guanghua Cai, Jie Wang, Xueyong Yang, Jinjing Sun. 2025. Functional analysis of CsAGL6 in flower development and pigmentation in cucumber (Cucumis sativus L.). Journal of Integrative Agriculture, Doi:10.1016/j.jia.2025.11.012

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