title: Physiological and molecular analysis of the maturation process in fruits of Clementine Mandarin and one of its late-ripening mutants.
abstract: Peel color is one of the main features affecting citrus quality. Clementine is a widespread citrus species with several mutants showing a delay in pigmentation and harvesting. This work characterizes the fruit development and ripening of two clementine clones, 'Comune', a widespread variety, and one of its natural mutations, 'Tardivo', which differ by a delayed color-break and extended harvest period. Morphological, chemical, and molecular analyses were carried out on fruits of both genotypes during the whole maturation process. Analysis showed that mutation did not affect ripening characteristics such as juice acidity and TSS. However, biochemical and molecular analysis revealed marked differences in the flavedo regarding carotenogenesis and chlorophyllase gene expression. Carotenoid showed quantitative differences at biochemical and molecular levels. Results demonstrated that the mutation in 'Tardivo' influenced the transcriptional activation of PSY, a key step in carotenoid biosynthesis. The differential PSY expression led to a significant quantitative difference in phytoene accumulation between the two genotypes. Also, 'Tardivo' showed delayed accumulation of carotenes, lutein, and beta,beta-xanthophylls. The differential expression of genes involved in ethylene biosynthesis and perception suggested differing responses to ethylene signaling between the two genotypes. Moreover, exogenous application of ethylene revealed a different sensitivity of the two varieties to this hormone. The analysis added new information to better understand the complex process of ripening in citrus.
authors: Dipartimento di OrtoFloroArboricoltura e Tecnologie Agroalimentari, University of Catania, 95123 Catania, Italy.
authors: Gaetano
authors: G
authors: Distefano
authors: Giuseppina
authors: G
authors: Las Casas
authors: Marco
authors: M
authors: Caruso
authors: Aldo
authors: A
authors: Todaro
authors: Paolo
authors: P
authors: Rapisarda
authors: Stefano
authors: S
authors: La Malfa
authors: Alessandra
authors: A
authors: Gentile
authors: Eugenio
authors: E
authors: Tribulato
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics; D002338:Carotenoids / Q000032:analysis / Q000235:genetics; D002957:Citrus / Q000235:genetics*; D005030:Ethylenes / Q000008:administration & dosage / Q000096:biosynthesis; D005638:Fruit / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development*; D015870:Gene Expression / Q000235:genetics; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D009154:Mutation
chemical_list: D005030:Ethylenes; D002338:Carotenoids; C036216:ethylene; D019883:Alkyl and Aryl Transferases; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase