Role of abscisic acid and ethylene in sweet cherry fruit maturation: molecular aspects

摘要

To investigate the role of abscisic acid (ABA) and ethylene in the maturation of sweet cherry fruit, cloning was carried out on one cDNA (PacNCED1 ) encoding 9-cis-epoxycarotenoid dioxygenase (NCED)—a key enzyme in ABA biosynthesis—and on one cDNA (PacACO1 ) encoding 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase—an enzyme involved in ethylene biosynthesis. A BLAST homology search revealed that the sequences of DNA and amino acids in both PacNCED1 and PacACO1 showed a high degree of homology to comparable molecules of other plant species. The expression of PacNCED1 increased at the beginning of maturation and peaked 4 days before harvest, which was consistent with ABA accumulation during cherry ripening. Application of exogenous ABA increased the ABA content, inducing the expression of PacNCED1 , and promoted ripening via enhancing colour formation and sugar accumulation. The expression of PacACO1 was not observed, and ethylene production was below detection levels, during the entire process of fruit development. The application of ABA or ethephon induced the expression of PacACO1 and stimulated ethylene biosynthesis. The results suggested that ABA—regulated by PacNCED1 —may be the key factor in the control of sweet cherry fruit ripening. Exogenous ABA stimulated ethylene production via regulation of PacACO1 expression, which indicated that cherry fruits may have the potential to synthesize ethylene.