title: Abscisic acid plays an important role in the regulation of strawberry fruit ripening.
abstract: The plant hormone abscisic acid (ABA) has been suggested to play a role in fruit development, but supporting genetic evidence has been lacking. Here, we report that ABA promotes strawberry (Fragaria ananassa) fruit ripening. Using a newly established Tobacco rattle virus-induced gene silencing technique in strawberry fruit, the expression of a 9-cis-epoxycarotenoid dioxygenase gene (FaNCED1), which is key to ABA biosynthesis, was down-regulated, resulting in a significant decrease in ABA levels and uncolored fruits. Interestingly, a similar uncolored phenotype was observed in the transgenic RNA interference (RNAi) fruits, in which the expression of a putative ABA receptor gene encoding the magnesium chelatase H subunit (FaCHLH/ABAR) was down-regulated by virus-induced gene silencing. More importantly, the uncolored phenotype of the FaNCED1-down-regulated RNAi fruits could be rescued by exogenous ABA, but the ABA treatment could not reverse the uncolored phenotype of the FaCHLH/ABAR-down-regulated RNAi fruits. We observed that down-regulation of the FaCHLH/ABAR gene in the RNAi fruit altered both ABA levels and sugar content as well as a set of ABA- and/or sugar-responsive genes. Additionally, we showed that exogenous sugars, particularly sucrose, can significantly promote ripening while stimulating ABA accumulation. These data provide evidence that ABA is a signal molecule that promotes strawberry ripening and that the putative ABA receptor, FaCHLH/ABAR, is a positive regulator of ripening in response to ABA.
authors: Beijing Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China.
authors: Hai-Feng
authors: HF
authors: Jia
authors: Ye-Mao
authors: YM
authors: Chai
authors: Chun-Li
authors: CL
authors: Li
authors: Dong
authors: D
authors: Lu
authors: Jing-Jing
authors: JJ
authors: Luo
authors: Ling
authors: L
authors: Qin
authors: Yuan-Yue
authors: YY
authors: Shen
mesh_terms: D000040:Abscisic Acid / Q000502:physiology*; D001483:Base Sequence; D017931:DNA Primers; D015536:Down-Regulation; D031985:Fragaria / Q000235:genetics / Q000502:physiology*; D020868:Gene Silencing; D017343:Genes, Plant; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D034622:RNA Interference; D012323:RNA Processing, Post-Transcriptional; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D000040:Abscisic Acid