Detecting the physiological and molecular mechanisms by which abscisic acid (ABA) regulates the consistency of sweet cherry fruit maturity

In the cultivation and production of sweet cherry, the cost of picking fruit is high due to inconsistency in the maturation period, which has affected the development of the cherry industry. In this study, the effects of exogenous abscisic acid (ABA) on the sweet cherry variety 'Luying 3' fruit quality and maturation stage were observed and recorded, and the physiological and molecular mechanisms were explored to systematically analyze the effects of ABA on sweet cherry fruit ripening to promote the development of the cherry industry. Exogenous ABA (400 mg L^-1) enhanced the color of 'Luying 3' fruit in the developing stage but had no significant effect on the fruit weight, soluble solid content, titratable acid content, and sugar-acid ratio in the mature stage. The application of ABA significantly promoted the secretion of endogenous ABA, gibberellin (GA) and salicylic acid (SA). A total of 766 differentially expressed genes (DEGs) were obtained between the treatment group and the control group at 47 and 54 d after flowering. The DEGs were significantly enriched in plant hormone signal transduction pathway, MAPK plant signal transduction pathway and glycolysis pathway. Six genes related to the synthesis of endogenous hormones were screened, of which five were upregulated and one was downregulated. Four DEGs related to the sweet cherry fruit metabolic rate were upregulated by ABA, which positively regulated fruit ripening. Eight differentially expressed AP2/ERF transcription factors were identified, of which 5 were upregulated and 3 were downregulated. This study provides a theoretical foundation for the application of ABA in promoting the consistency of cherry fruit maturity.