A GAMYB homologue CsGAMYB1 regulates sex expression of cucumber via an ethylene-independent pathway.
Cucumber (Cucumis sativus L.) is a typical monoecious vegetable with individual male and female flowers, and has been used as a model plant for sex determination. It is well known that sex differentiation of cucumber can be regulated by phytohormones, such as gibberellic acid (GA) and ethylene. The molecular mechanism of female sex expression modulated by ethylene has been widely understood, but how GA controls male sex expression remains elusive. In hermaphroditic Arabidopsis and rice, GA can regulate stamen and anther development via the transcriptional regulation of GAMYB. Here we characterized a GAMYB homologue CsGAMYB1 in cucumber. We found that CsGAMYB1 is predominantly expressed in male flower buds, where its expression is upregulated by GA3 treatment. CsGAMYB1 protein is localized in the nucleus. CsGAMYB1 can partially rescue stamen development and fertility phenotypes of an Arabidopsis myb33 myb65 double mutant. However, constitutive overexpression of CsGAMYB1 in wild-type Arabidopsis resulted in male sterility, which mimics the effect of GA overdose in flower development. Knockdown of CsGAMYB1 in cucumber decreases the ratio of nodes with male and female flowers, and ethylene is not involved in this process. Our data suggest that CsGAMYB1 regulates sex expression of cucumber via an ethylene-independent pathway.
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, P. R. China Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, P. R. China.
Yan
Y
Zhang
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, P. R. China Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, P. R. China.
Xiaolan
X
Zhang
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, P. R. China Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, P. R. China.
Bin
B
Liu
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, P. R. China Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, P. R. China.
Wenjiao
W
Wang
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, P. R. China Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, P. R. China.
Xingwang
X
Liu
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, P. R. China Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, P. R. China.
Chunhua
C
Chen
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, P. R. China Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, P. R. China.
Xiaofeng
X
Liu
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, P. R. China Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, P. R. China.
Sen
S
Yang
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, P. R. China Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, P. R. China renhuazhong@cau.edu.cn.
Huazhong
H
Ren
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D018553:Cucumis sativus / Q000235:genetics* / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D005030:Ethylenes; D005875:Gibberellins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors; C036216:ethylene; C007842:gibberellic acid
CsGAMYB1; GAMYB; cucumber; ethylene; gibberellin; sex expression.