title: CsAP3: A Cucumber Homolog to Arabidopsis APETALA3 with Novel Characteristics.
abstract: In our previous efforts to understand the regulatory mechanisms of cucumber unisexual flower development, we observed a stamen-specific down-regulation of the ethylene receptor CsETR1 in stage 6 female flowers of cucumber (Cucumis sativus L.). This down-regulation is correlated with the primordial anther-specific DNA damage that characterizes inappropriate stamen development in cucumber female flowers. To understand how CsETR1 is down regulated in the stamen, we characterized a cucumber MADS box gene homologous to Arabidopsis AP3, CsAP3. We demonstrated that CsAP3 is functionally equivalent to the Arabidopsis B-class MADS gene AP3. However, three novel characteristics of CsAP3 were found. These include firstly, binding and activating CsETR1 promoter in vitro and in vivo; secondly, containing a GV repeat in its C-terminus, which is conserved in cucurbits and required for the transcription activation; and thirdly, decreased expression as the node number increases, which is similar to that found for CsETR1. These findings revealed not only the conserved function of CsAP3 as a B-class floral identity gene, but also its unique functions in regulation of female flower development in cucumber.
authors.affiliation: State Key Laboratory of Protein and Plant Gene ResearchBeijing, China; Institute of Vegetables and Flowers, Chinese Academy of Agricultural SciencesBeijing, China; College of Life Sciences, Peking UniversityBeijing, China.
authors.forename: Jin-Jing
authors.initials: JJ
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Protein and Plant Gene ResearchBeijing, China; College of Life Sciences, Peking UniversityBeijing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.affiliation: State Key Laboratory of Protein and Plant Gene ResearchBeijing, China; College of Life Sciences, Peking UniversityBeijing, China.
authors.forename: Dong-Hui
authors.initials: DH
authors.lastname: Wang
authors.affiliation: Department of Vegetable Sciences, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University Beijing, China.
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Liu
authors.affiliation: College of Life Sciences, Peking University Beijing, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Protein and Plant Gene ResearchBeijing, China; College of Life Sciences, Peking UniversityBeijing, China.
authors.forename: Na
authors.initials: N
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Protein and Plant Gene ResearchBeijing, China; College of Life Sciences, Peking UniversityBeijing, China.
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Gu
authors.affiliation: State Key Laboratory of Protein and Plant Gene ResearchBeijing, China; College of Life Sciences, Peking UniversityBeijing, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zou
authors.affiliation: College of Life Sciences, Peking University Beijing, China.
authors.forename: Jing-Chu
authors.initials: JC
authors.lastname: Luo
authors.affiliation: Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Chao-Xing
authors.initials: CX
authors.lastname: He
authors.affiliation: Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: San-Wen
authors.initials: SW
authors.lastname: Huang
authors.affiliation: Department of Vegetable Sciences, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University Beijing, China.
authors.forename: Xiao-Lan
authors.initials: XL
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Protein and Plant Gene ResearchBeijing, China; College of Life Sciences, Peking UniversityBeijing, China.
authors.forename: Zhi-Hong
authors.initials: ZH
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Protein and Plant Gene ResearchBeijing, China; College of Life Sciences, Peking UniversityBeijing, China; National Center of Plant Gene ResearchBeijing, China.
authors.forename: Shu-Nong
authors.initials: SN
authors.lastname: Bai
keywords: MADS box genes; cucumber; ethylene; stamen arrestment; unisexual flower development