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a b s t r a c t UV-C treatment applied during postharvest to control fruit decay has been shown to interfere with several aspects of fruit quality. In this study, strawberry fruit (Fragaria  ananassa Duch., cv 'Aromas') harvested at the 75% red stage of ripening were treated with UV-C (4.35 kJ m À2 ) and postharvest compounds indicative of quality, as well as related gene transcripts, were measured. UV-C effect in two allergenic proteins was also evaluated. After treatment, fruit was stored for six days at 20 ± 2 C and 80 ± 5% relative humidity (RH). UV-C treated fruit maintained flesh firmness and showed lower pectate lyase transcript accumulation than control fruit. UV-C treatment increased total anthocyanin and phenolic compounds, including gallic acid, hydroxybenzoic acid, r-coumaric acid, quercetin and (þ)-catechin. UV-C treatment also increased L-galactose dehydrogenase, L-galactono-1,4-lactone dehydrogenase, alcohol dehydrogenase and alcohol acetyl transferase transcript accumulation, and resulted in strawberries with higher L-ascorbic acid content and higher volatile compound production. In conclusion, UV-C treatment induces a variety of changes in the strawberry primarily via gene activation, resulting in firmer fruit with higher levels of bioactive molecules, as well as a stronger aroma. However, UV-C also induced accumulation of the putatively allergenic protein Fra a1.

International audienceUltraviolet-C (UV-C) radiation is used as a postharvest treatment to prolong the shelf life of fruit.However, this stressful process may also affect ethylene production and, consequently, the expression of genes encoding ethylene response factors (ERFs). To test this hypothesis, MicroTom tomatoes harvested at the breaker stage were subjected to: 1 – application of 3.7 kJ m-2 UV-C radiation, 2 – application of 2 µLL-1 1-methylcyclopropene (1-MCP) followed by UV-C radiation; and 3 – without 1-MCP or UV-C (control treatment). After treatment all fruit were stored for 12 d at 21 +/- 2C° and 80 +/- 5% relative humidity (RH). Although UV-C radiation increased ACC oxidase transcripts and stimulated ethylene production, the ripening evolution was delayed. Fruit treated with UV-C showed lower accumulation of lycopene, b-carotene, lutein + zeaxanthin and d-tocopherol; but retained higher levels of chlorogenic acid, r-coumaric acid and quercetin after 6 d. Additionally, UV-C treated fruit had higher contents of polyamines (putrescine and spermidine). Among the 14 ERFs studied, 11 (Sl-ERF A.1, Sl-ERF A.3,Sl-ERF B.1, Sl-ERF B.2, Sl-ERF B.3, Sl-ERF C.6, Sl-ERF D.1, Sl-ERF D.3, Sl-ERF E.1, Sl-ERF F.5, Sl-ERF G.2) exhibited increased transcript accumulation, 2 ERFs (Sl-ERF E.2 and Sl-ERF E.4) showed decreased transcript accumulation and only 1 ERF (Sl-ERF E.3) was not significantly affected by UV-C treatment. As expected, the transcript profiles of 1-MCP and/or UV-C-treated tomatoes demonstrate that ethylene plays an important role in the expression of ERFs. The delay in fruit ripening may be caused by the activation of ERFs that could act as regulators of metabolic pathways during ripening. However, this hypothesis needs to be better tested. In conclusion, a relationship has been established between UV-C treatment and ripening delay, correlated to changes in 13 ERF transcripts evaluated during postharvest treatment

Postharvest texture change is a fundamental question for fruit growers and breeders as it drives consumer acceptability. To decipher the genetic control of fruit texture, we studied an apple segregating population over 2 years at harvest and after 2 months of cold storage. Texture complexity was dissected in quantitative traits, related to (i) sensory perception of fruit quality and (ii) fruit mechanical properties. Genetic models including storage, genotype and their interaction effects were built. After selection of a model, broad sense heritabilities were estimated. Strong genetic and storage effects were identified for all texture traits with significant interaction. Moreover, the structure of traits co-variations was preserved after storage. Based on the new integrated genetic map, numerous quantitative trait loci (QTLs) were detected, revealing multigenic control of fruit texture traits. QTLs were clustered according to the kind of texture assessment i.e. penetrometry, compression and sensory. Moreover, QTL stability over years and storage periods was investigated. Lastly, a short list of relevant texture traits, such as fruit global hardness and fruit deformation until skin failure, is proposed to optimize texture phenotyping for future quantitative genetic studies