Beijing Key Laboratory of New Technology in Agricultural Application, College of Plant Science and Technology, Beijing University of Agriculture, No. 7 Beinong Road, Changping District, Beijing 102206, PR China.
J Exp Bot. 2013 Apr;64(6):1677-87. doi: 10.1093/jxb/ert028. Epub 2013 Feb 11.
Although a great deal of progress has been made toward understanding the role of abscisic acid (ABA) in fruit ripening, many components in the ABA signalling pathway remain to be elucidated. Here, a strawberry gene homologous to the Arabidopsis gene ABI1, named FaABI1, was isolated and characterized. The 1641bp cDNA includes an intact open reading frame that encodes a deduced protein of 546 amino acids, in which putative conserved domains were determined by homology analysis. Transcriptional analysis showed that the levels of FaABI1 mRNA expression declined rapidly during strawberry fruit development as evidenced by real-time PCR, semi-quantitative reverse transcription-PCR, and northern blotting analyses, suggesting that the Ser/Thr protein phosphatase PP2C1 encoded by FaABI1 may be involved in fruit ripening as a negative regulator. The results of Tobacco rattle virus-induced gene silencing and PBI121 vector-mediated overexpression suggested that the down- and up-regulation of FaABI1 mRNA expression levels in degreening strawberry fruit could promote and inhibit ripening, respectively. Furthermore, alteration of FaABI1 expression could differentially regulate the transcripts of a set of both ABA-responsive and ripening-related genes, including ABI3, ABI4, ABI5, SnRK2, ABRE1, CHS, PG1, PL, CHI, F3H, DFR, ANS, and UFGT. Taken together, the data provide new evidence for an important role for ABA in regulating strawberry fruit ripening in the processes of which the type 2C protein phosphatase ABI1 serves as a negative regulator. Finally, a possible core mechanism underlying ABA perception and signalling transduction in strawberry fruit ripening is discussed.
尽管在理解脱落酸（ABA）在果实成熟中的作用方面已经取得了很大进展，但 ABA 信号通路中的许多成分仍有待阐明。在这里，我们分离并鉴定了一个与拟南芥基因 ABI1 同源的草莓基因，命名为 FaABI1。该基因的 cDNA 全长 1641bp，包含一个完整的开放阅读框，编码一个由 546 个氨基酸组成的推定蛋白，通过同源性分析确定了推定的保守结构域。转录分析表明，实时 PCR、半定量 RT-PCR 和 northern blot 分析表明，FaABI1 mRNA 的表达水平在草莓果实发育过程中迅速下降，提示由 FaABI1 编码的丝氨酸/苏氨酸蛋白磷酸酶 PP2C1 可能作为负调控因子参与果实成熟。烟草脆裂病毒诱导的基因沉默和 PBI121 载体介导的过表达的结果表明，脱绿草莓果实中 FaABI1 mRNA 表达水平的下调和上调分别促进和抑制了果实成熟。此外，FaABI1 表达的改变可以差异调节一组 ABA 响应和成熟相关基因的转录本，包括 ABI3、ABI4、ABI5、SnRK2、ABRE1、CHS、PG1、PL、CHI、F3H、DFR、ANS 和 UFGT。总之，这些数据为 ABA 在调控草莓果实成熟过程中发挥重要作用提供了新的证据，其中 2C 型蛋白磷酸酶 ABI1 作为负调控因子。最后，讨论了 ABA 感知和信号转导在草莓果实成熟中的可能核心机制。
