Type 2C protein phosphatase ABI1 is a negative regulator of strawberry fruit ripening

Abstract

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.

SUCROSE NONFERMENTING1-RELATED PROTEIN KINASE2.6, an Ortholog of OPEN STOMATA1, Is a Negative Regulator of Strawberry Fruit Development and Ripening

“…Previous studies demonstrated that ABA as well as PYR1 and FaABI1 were involved in the regulation of strawberry fruit development and ripening Jia et al, 2011Jia et al, , 2013a. It is not surprising that PYR1 and ABI1 are implicated in strawberry fruit development and ripening, because molecular interaction between PYR and ABI1 is required to initiate ABA signaling.…”

“…Collectively, these results strongly indicate that FaSnRK2.6 plays a critical role in the regulation of strawberry fruit development and ripening. A previous study demonstrated that FaABI1, a key signal in the ABA signaling cascade, is a negative regulator of strawberry fruit development and ripening (Vlad et al, 2009;Jia et al, 2013a). We here examined the physical interaction between FaSnRK2.6 and FaABI1.…”

“…Recently, ABA was shown to act as an internal cue that plays an important role in strawberry fruit ripening . Furthermore, it was reported that manipulating the expression of either an ABA receptor, strawberry PYRABACTIN RESISTANCE1 (FaPYR1), or its downstream signaling component, strawberry ABSCISIC ACID INSENSITIVE1 (FaABI1), affects strawberry fruit ripening Jia et al, 2013a). Given that OST1 is a critical mediator of ABA signaling, it is possible that the strawberry ortholog of OST1 plays an important role in strawberry fruit development and ripening.…”

RNAi-mediated silencing and overexpression of the FaMYB1 gene and its effect on anthocyanin accumulation in strawberry fruit

“…Knockdown of an ABA receptor or an ABA synthetic enzyme leads to an uncoloured phenotype ). In addition, type 2C protein phosphatase, ABI1, involved in ABA signaling, negatively regulates strawberry fruit ripening (Jia et al 2013). However, signal transduction following irradiance or ABA treatment remains to be characterized.…”

Acylphloroglucinol biosynthesis in strawberry fruit

“…During fruit ripening, flavonoids and anthocyanins are synthesized by highly complex but coordinated pathways that are regulated at the levels of signal reception (Jia et al, 2011), signal transduction (Jia et al, 2013), transcription factors (Medina-Puche et al, 2014), and structural genes (Griesser et al, 2008). In addition, complex feedback mechanisms controlling anthocyanin synthesis have been described (Muñoz et al, 2010).…”