Cinnamyl alcohol dehydrogenases in the mesocarp of ripening fruit of Prunus persica genotypes with different flesh characteristics: changes in activity and protein and transcript levels

Abstract

Development of fruit flesh texture quality traits may involve the metabolism of phenolic compounds. This study presents molecular and biochemical results on the possible role played by cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) during ripening [S3, S4 I (pre-climacteric) and S4 III (climacteric) stages] of peach [Prunus persica (L.) Batsch] fruit with different flesh firmness [non-melting flesh (NMF) 'Oro A'/melting flesh (MF) 'Springcrest' and 'Sanguinella'] and color (blood-flesh Sanguinella). A total of 24 putative full-length PRUPE_CAD genes were identified (in silico analysis) in the peach genome. The most abundant CAD isoforms, encoded by genes located on scaffolds 8 and 6, were probed by specifically developed anti-PRUPE_CAD sc8 and by anti-FaCAD (PRUPE_CAD sc6) polyclonal antibodies, respectively. PRUPE_CAD sc8 proteins (SDS-PAGE and native-PAGE/western blot) appeared responsible for the CAD activity (in vitro/in-gel assays) that increased with ripening (parallel to PRUPE_ACO1 transcripts accumulation and ethylene evolution) only in the mesocarp of Oro A and blood-flesh Sanguinella. Accumulation of PRUPE_CAD sc8 transcripts (semi-quantitative RT-PCR) occurred in all three cultivars, but in Oro A and Springcrest it was not always accompanied by that of the related proteins, suggesting possible post-transcriptional regulation. Flesh firmness, as well as levels of lignin, total phenolics and, where present (Sanguinella), anthocyanins, declined with ripening, suggesting that, at least in the studied peach cultivars, CAD activity is related to neither lignification nor differences in flesh firmness (NMF/MF). Further studies are necessary to clarify whether the high levels of CAD activity/expression in Sanguinella play a role in determining the characteristics of this blood-flesh fruit.

Cell wall metabolism of peaches and nectarines treated with UV‐B radiation: a biochemical and molecular approach

“…Despite NMF fruit showed lower flesh firmness than MF at harvest, this parameter was maintained essentially constant after 36 h, consistent with evidence on the narrower changes in flesh firmness of NMF fruit compared to MF . A similar behaviour was observed in the NMF cultivar Oro A . Reports are available on the effects of UV‐C radiation in contrasting flesh firmness decrease during shelf life in apple and tomato; in this last species the effect was accompanied by the inhibition of the synthesis/expression of cell wall‐degrading enzymes .…”

“…30,62 A similar behaviour was observed in the NMF cultivar Oro A. 63 Reports are available on the effects of UV-C radiation in contrasting flesh firmness decrease during shelf life in apple 64 and tomato; 12,13 in this last species the effect was accompanied by the inhibition of the synthesis/expression of cell wall-degrading enzymes. 13 Conflicting results have been reported on the effects of UV-B on fruit firmness.…”

Characterization and analysis of CCR and CAD gene families at the whole-genome level for lignin synthesis of stone cells in pear (Pyrus bretschneideri) fruit

“…Although PbCAD11 and PbCAD26 were found to be closely related to PtSAD , their expression levels were inconsistent with the peak of lignin content, with up-regulated expression only in the fruit-ripening stage (145 DAF). In addition, PbCAD19 , - 20 , - 25 and - 26 were also significantly up-regulated during fruit ripening, which may be related to tissue maturation or ageing ( Singh et al, 2010 ; Gabotti et al, 2015 ).

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PpYUC11, a strong candidate gene for the stony hard phenotype in peach (Prunus persicaL. Batsch), participates in IAA biosynthesis during fruit ripening

“…Leaves, stems, and stem tips of ‘Goldhoney 3’ at the vegetative growth stage as well as flowers at the full bloom stage were collected during the spring of 2014. Fruit growth stages were defined according to Tonutti et al (1997) and Gabotti et al (2015) . At the desired times (from the S3 to the S4 stage at eight time points), fruits of ‘Goldhoney 3’ and ‘Yumyeong’ were picked and quickly transferred to the laboratory for the determination of weight and ripening parameters (ethylene production, flesh firmness, and soluble solids content).…”