Pleiotropic effects of CmACS7 on fruit growth and quality parameters in melon (Cucumis melo)
CmACS7 is a sex determination gene that is known to be involved in the biosynthesis of ethylene at very early stages of pistillate flower development in melon, promoting so the arrest of stamen during the development of female flowers, and resulting in monoecious plants. Loss-of-function mutations for CmACS7 reduce the production of ethylene in pistillate flowers, which results in hermaphrodite flowers and andromonoecious plants. In this paper we compare fruit growth and quality in monoecious and andromonoecious isogenic lines of five different genotypes of 'Galia' (Cucumis melo var. reticulatus) and 'Cantaloupe' (Cucumis melo var. cantalupensis) melons. The gene not only regulates sex determination but also other fruit growth parameters. The mutation that caused andromonoecy and reduced ethylene in female flowers promoted a reduction in fruit set, fruit weight and number of total and viable seeds, as well as an alteration of fruit shape in the five genotypes analyzed. In some genotypes monoecy stability was reduced, concomitantly with a loss of significant differences between isogenic lines. The gene mutation, however, had no effect on fruit quality parameters such as total soluble solids, fruit pH and titratable acidity. To assess whether these pleiotropic effects of the gene are associated with ethylene biosynthesis, we analyzed production of ethylene in the ovary/fruit of unpollinated flowers during the days immediately after anthesis, confirming a higher induction of ethylene in the monoecious isoline. Results are discussed in relation to ethylene production and autoregulation of ethylene biosynthesis in flowers and fruits.
Martos-Fuentes, M., Lizarzaburu, J.A., Aguayo, E., Martínez, C. and Jamilena, M. (2017). Pleiotropic effects of CmACS7 on fruit growth and quality parameters in melon (Cucumis melo). Acta Hortic. 1151, 115-120
fruit set, seed quantity and quality, fruit quality, 'Cantaloupe', 'Galia'