Catálogo de publicaciones - libros

The phytohormone ethylene is well known to influence a number of physiological and developmental processes in plants including but not limited to seed germination, seedling growth, formation of the apical hook, senescence, fruit ripening, abscission, and gravitropism (Abeles . 1992).

The known components involved in ethylene signaling generally form a linear pathway model, beginning with ethylene binding at the receptors and resulting in the activation of ethylene-response genes (Guo and Ecker, 2004). Elucidation of this pathway has been possible through the isolation of genetic mutants displaying altered responses to ethylene. seedlings grown in the dark in the presence of ethylene exhibit a “triple response”, which consists of inhibition of hypocotyl and root elongation, radial swelling of the hypocotyl, and an exaggerated curvature of the apical hook (Bleecker ., 1988; Guzman and Ecker, 1990).

The miniature potted roses are popular greenhouse crops in many parts of the world. In the 1980s the introduction of new varieties had a dramatic impact on the European and North American markets. Current world production is estimated at around 100 million pots yearly. Major centers of production include Denmark, the Netherlands, the United States, Canada and Japan with production also in France, Germany and Italy (Pemberton , 2003).

Ethylene perception and signal transduction involves a multistep pathway, in which ethylene receptors act at the first step and play a crucial role by negatively regulating ethylene responses (Chang and Stadler, 2001). In this respect, ethylene receptors have received considerable attention, as knowledge regarding this system would provide important contributions to our understanding of the mechanisms of ethylene signaling, and also provide the means to develop effective approaches for engineering ethylene sensitivity in plants. To better understand the biochemical mechanism of ethylene receptor action, we examined the subcellular localization and membrane topology that are important determinants of the biochemical functions of multispanning membrane proteins.

Export bananas (, cv Cavendish) of the French West Indies are usually subjected to the “mixed-ripe” and/or “ship-ripe” processes during transit with a rapid deterioration of their quality. We hypothesized that this post harvest process is associated with the level of fruit ethylene responsiveness at harvest time. We attempted to obtain insight at the molecular level by identifying related candidate genes, which could be used as markers to improve the post harvest quality of fruit.

Natural rubber is mostly produced by and represents 33% of total consumed rubber in the world, its production reaching 7.92 million tons in 2003. Heveaculture takes advantage of the increase in demand for natural rubber and the ecological challenges (carbon sequestration) to be a major renewable source of rubber and wood.

From studies on ethylene biosynthesis in the pasture legume white clover ( L.), it is clear that transcription of the two committed enzymes in the pathway, ACC synthase and ACC oxidase, is under strict developmental control, as is common in many plant species (Chen and McManus, 2006; Hunter , 1999; Murray and McManus, 2005). In terms of post-translational control, there is now evidence from studies with the model plant that ACC synthase activity is regulated by phosphorylation (Tatsuki and Mori, 2001). However, no similar evidence has been presented for ACC oxidase.

It is now well established in plants that ACC oxidase comprises a small multigene family of typically 4–5 members. Further, in many of the species studied, this gene family displays differential expression in response to developmental, tissue-specific stimuli, and/or environmental cues (Barry ., 1996; Hunter ., 1999). In apple (), an ACC oxidase gene that is associated with fruit ripening has been identified (Ross ., 1992), as well as a fruit-associated isoform purified and characterised in terms of kinetic properties (Pirrung ., 1993). However, very little is known about the other members of the gene family in apple.

Ethylene perception and signal transduction elements are conserved among various plants species where they have been examined, suggesting their importance in plant development and survival. The ethylene receptor multigene family can be divided into subfamily 1 and 2. Previous studies in our laboratory have isolated and characterized and (Sato-Nara , 1999; Takahashi , 2002; Ma , 2006).

The role of ethylene in non-climacteric ripening is not clear yet. The objective of our experiments was to isolate genes involved in ethylene biosynthe sis and signal transduction in strawberry ( × , a nonclimacteric fruit. For this purpose, RT-PCR was used on RNA templates derived from different parts of strawberry plants (young and old leaves, runners and runner tips), fruits of four ripening stages and ripe fruits diseased by .