Rapid appearance of an mRNA correlated with ethylene synthesis encoding a protein ofmolecular weight 35000

Abstract

Changes in gene expression related to ethylene synthesis were investigated during ripening of tomato fruit, and in unripe fruit and leaves after wounding. Messenger RNA was extracted at different stages of ripening, or at various times after wounding, and translated in vitro. A number of changes in mRNA were noted in all cases, including an increase in one encoding a protein of MW 35000. The mRNA encoding this protein in ripening fruit was hybrid-selected by a ripening-related complementary DNA clone, pTOM13. This clone also selected an mRNA encoding a protein of MW 35000 from RNA extracted from wounded unripe fruit and wounded leaves, but not from unwounded control tissue. During ripening and after wounding the appearance of mRNA for the MW-35000 protein was correlated with increased ethylene synthesis. In unripe fruit, the increase in mRNA for the MW-35000 protein and in ethylene synthesis were detected within 30 min of wounding. In-vivo labelling showed that a protein of MW 35000 was also synthesised rapidly in wounded fruit tissue. We suggest that the mRNAs encoding the MW-35000 proteins that increased during ripening and in response to wounding are the same and may be related to ethylene synthesis.