A role of brassinosteroids in early fruit development in cucumber.
Brassinosteroids (BRs) are essential for many biological processes in plants, however, little is known about their roles in early fruit development. To address this, BR levels were manipulated through the application of exogenous BRs (24-epibrassinolide, EBR) or a BR biosynthesis inhibitor (brassinazole, Brz) and their effects on early fruit development, cell division, and expression of cyclin and cyclin-dependent kinases (CDKs) genes were examined in two cucumber cultivars that differ in parthenocarpic capacity. The application of EBR induced parthenocarpic growth accompanied by active cell division in Jinchun No. 4, a cultivar without parthenocarpic capacity, whereas Brz treatment inhibited fruit set and, subsequently, fruit growth in Jinchun No. 2, a cultivar with natural parthenocarpic capacity, and this inhibitory effect could be rescued by the application of EBR. RT-PCR analysis showed both pollination and EBR induced expression of cell cycle-related genes (CycA, CycB, CycD3;1, CycD3;2, and CDKB) after anthesis. cDNA sequences for CsCycD3;1 and CsCycD3;2 were isolated through PCR amplification. Both CsCycD3;1 and CsCycD3;2 transcripts were up-regulated by EBR treatment and pollination but strongly repressed by Brz treatment. Meanwhile, BR6ox1 and SMT transcripts, two genes involved in BR synthesis, exhibited feedback regulation. These results strongly suggest that BRs play an important role during early fruit development in cucumber.
Department of Horticulture, Huajiachi Campus, Zhejiang University, Kaixuan Road 268, Hangzhou, PR China.
Feng Qing
FQ
Fu
Wei Hua
WH
Mao
Kai
K
Shi
Yan Hong
YH
Zhou
Tadao
T
Asami
Jing Quan
JQ
Yu
D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D060406:Brassinosteroids; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002455:Cell Division; D002777:Cholestanols / Q000378:metabolism*; D018553:Cucumis sativus / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000502:physiology; D005638:Fruit / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000378:metabolism; D037121:Plant Lectins / Q000145:classification / Q000235:genetics; D054817:Pollination; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D013260:Steroids, Heterocyclic / Q000378:metabolism*
D029681:Arabidopsis Proteins; D060406:Brassinosteroids; D018797:Cell Cycle Proteins; D002777:Cholestanols; C496944:CycD3 protein, Arabidopsis; D016213:Cyclins; D010937:Plant Growth Regulators; D037121:Plant Lectins; D013260:Steroids, Heterocyclic; C023623:brassinolide