Background: Oligogalacturonic acids (OGs) are oligomers of alpha-1,4-linked galacturonosyl residues that are released from cell walls by the hydrolysis of polygalacturonic acids upon fruit ripening and under abiotic/biotic stress. OGs may induce ethylene production and fruit ripening, however, the mechanism(s) behind these processes is unknown. Results: Tomato cultivar 'Ailsa Craig' (AC) and mutant Neverripe, ripening inhibitor, non-ripening, and colorless non-ripening fruits were treated with OGs at different stages. Only AC fruits at mature green stage 1 showed an advanced ripening phenomenon, although transient ethylene production was detected in all of the tomato fruits. Ethylene synthesis genes LeACS2 and LeACO1 were rapidly up-regulated, and the phosphorylated LeACS2 protein was detected after OGs treatment. Protein kinase/phosphatase inhibitors significantly affected the ripening process induced by the OGs. As a potential receptor of OGs, LeWAKL2 was also up-regulated in their presence. Conclusions: We demonstrated that OGs promoted tomato fruit ripening by inducing ethylene synthesis through the regulation of LeACS2 at transcriptional and post-translational levels.
Ma, Y., Zhou, L., Wang, Z., Chen, J., & Qu, G. (2016). Oligogalacturonic acids promote tomato fruit ripening through the regulation of 1-aminocyclopropane-1-carboxylic acid synthesis at the transcriptional and post-translational levels. BMC Plant Biology, 16(1). https://doi.org/10.1186/s12870-015-0634-y