The peach HECATE3-like gene FLESHY plays a double role during fruit development

Abstract

Tight control of cell/tissue identity is essential for a correct and functional organ patterning, an important component of overall fruit development and eventual maturation and ripening. Despite many investigations regarding the molecular determinants of cell identity in fruits of different species, a useful model able to depict the regulatory networks governing this relevant part of fruit development is still missing. Here we described the peach fruit as a system to link the phenotype of a slow ripening (SR) selection to an altered transcriptional regulation of genes involved in determination of mesocarp cell identity providing insight toward molecular regulation of fruit tissue formation. Morpho-anatomical observations and metabolomics analyses performed during fruit development on the reference cultivar Fantasia, compared to SR, revealed that the mesocarp of SR maintained typical immaturity traits (e.g. small cell size, high amino acid contents and reduced sucrose) throughout development, along with a strong alteration of phenylpropanoid contents, resulting in accumulation of phenylalanine and lignin. These findings suggest that the SR mesocarp is phenotypically similar to a lignifying endocarp. To test this hypothesis, the expression of genes putatively involved in determination of drupe tissues identity was assessed. Among these, the peach HEC3-like gene FLESHY showed a strongly altered expression profile consistent with pit hardening and fruit ripening, generated at a post-transcriptional level. A double function for FLESHY in channelling the phenylpropanoid pathway to either lignin or flavour/aroma is suggested, along with its possible role in triggering auxin-ethylene cross talk at the start of ripening.

Rosaceae Fruit Development, Ripening and Post-harvest: An Epigenetic Perspective

“…For these reasons H3K27me3 represents one of the main epigenetic marks able to determine specific expression patterns tissue-dependent and targeting genes involved in auxin response (perception, biosynthesis and signal transduction) (Lafos et al, 2011). In our recent research we have demonstrated that also in peach fruit, a putative post-transcriptional regulation of the TF FLESHY is likely to be mediated by miR710, confirming the relevant involvement of MIRNA loci in controlling the correct development of fruit (Botton et al, 2016). To confirm the possible role of PTMs in controlling of miRNA genesis the chromatin state analysis on MIRNA locus is under investigation.…”

“…This high correlation among different TFs involved in same pathways but in completely different fruit systems was confirmed in peach, where a high analogy, in terms of TFs involved (e.g., SEEDSTICK, STK, SHATTERPROOF, SHP, SECONDARY WALL THICKENING PROMOTING FACTOR, NTS1 ), between the regulation of the lignification in silique valve margin in Arabidopsis and the hardening of endocarp in peach was observed (Dardick et al, 2010; Dardick and Callahan, 2014). In particular the characterization of peach HEC3 -like gene FLESHY , showing a double function in channeling the phenylpropanoids pathway to either lignin or flavor/aroma, together with its possible role in triggering auxin-ethylene cross talk at the start of ripening, suggested the hypothesis, also in drupe patterning determination, of epigenetic control defined by chromatin specific epigenetic marks deposition (Botton et al, 2016). …”

Genome-Wide Identification, Expression Patterns, and Functional Analysis of UDP Glycosyltransferase Family in Peach (Prunus persica L. Batsch)

“…Hujingmilu) fruit, flowers, and leaves were obtained from the Melting Peach Research Institute of Fenghua, Zhejiang Province, China. Peach fruit were harvest at four stages (S1, S2, S3, and S4) according to previous study (Botton et al, 2016; Wang et al, 2016), representing the first fast growth (34 days after bloom, DAB, fruit weight = 5.69 ± 0.37 g), endocarp lignification (stone hardening, 71 DAB, 45.29 ± 0.63 g), the second fast growth (94 DAB, 113.93 ± 2.71 g), and mature stage (ready for harvest, 108 DAB, 207.48 ± 2.08 g), respectively. Peach fruit growth curve and photos of four stages were shown in Supplementary Figure S1 .…”

Metabolism of Stone Fruits: Reciprocal Contribution Between Primary Metabolism and Cell Wall

“…Additional information on lignin deposition in cell wall during drupe development and patterning have obtained from a Slow Ripening (SR) peach phenotype in which fruit development is apparently stopped during the stage III (Bonghi et al, 2011), and the flesh shows a very slow rate of softening accompanied by a low level of ethylene (Brecht and Kader, 1984). A metabolomic analysis of SR fruit, pointed out a strong accumulation of phenylpropanoids (in particular lignin and its precursors) in the mesocarp paralleled by the expression of phenylpropanoids biosynthetic genes (Botton et al, 2016). This evidence, together with microscopic analysis, suggests that SR mesocarp behaves like an endocarp.…”