In deciduous fruit trees, entrance into dormancy occurs in later summer/fall, concomitantly with the shortening of day length and decrease in temperature. Dormancy can be divided into endodormancy, ecodormancy and paradormancy. In Prunus species flower buds, entrance into the dormant stage occurs when the apical meristem is partially differentiated; during dormancy, flower verticils continue their growth and differentiation. Each species and/or cultivar requires exposure to low winter temperature followed by warm temperatures, quantified as chilling and heat requirements, to remove the physiological blocks that inhibit budburst. A comprehensive meta-analysis of transcriptomic studies on flower buds of sweet cherry, apricot and peach was conducted, by investigating the gene expression profiles during bud endo- to ecodormancy transition in genotypes differing in chilling requirements. Conserved and distinctive expression patterns were observed, allowing the identification of gene specifically associated with endodormancy or ecodormancy. In addition to the MADS-box transcription factor family, hormone-related genes, chromatin modifiers, macro- and micro-gametogenesis related genes and environmental integrators, were identified as novel biomarker candidates for flower bud development during winter in stone fruits. In parallel, flower bud differentiation processes were associated to dormancy progression and termination and to environmental factors triggering dormancy phase-specific gene expression.

In temperate zones, fruit trees regulate their annual growth cycle to seasonal environmental changes. During the cold season, growth is limited by both environmental and genetic factors. After the exposure to low temperature and fulfillment of chilling requirements, mild temperatures promote the growth and flowering. However, an insufficient chilling exposure may lead to nonuniform blooming, with a negative impact on fruit set.To gain insights into flower development in the fruit tree buds, peach is an interesting model, the flower and vegetative bud being distinct organs. To understand how flower bud development is regulated, we integrated cytological observations and epigenetic and chromatin genome-wide data with transcriptional changes to identify the main regulatory factors involved in flower development during chilling accumulation.We demonstrated that growth cessation does not occur in peach flower buds during chilling accumulation, but that there are changes in transcript abundance of key genes of hormone metabolism and flower bud development, distribution of histone modifications (H3K4me3 and H3K27me3) and DNA methylation.Altogether, our findings indicate that during the cold season the flower bud is in a nondormant state and that the chilling experience allows flower differentiation to be completed.

In Brazil winemaking is expanding not only in the renewal of vineyards in traditional production areas, but also in the introduction of new crops in the newer winemaking regions. Promising characteristics were observed in the quality of the grapes and wines produced in altitude regions of Santa Catarina. The aim of this study is to characterize the geographic and climatic conditions which affect the phenology and vegetative growth of grapevine in São Joaquim, in the mountains region of Santa Catarina. The vineyards are located in areas with undulated and strongly undulated relief, predominantly in soils originating from basaltic rocks, in climate conditions classified as Cfb according to the Köppen, as Region I according to Winkler classification. The phenological stage of the grapevines in the São Joaquim region begins later and lasts longer in comparison to other winegrowing regions in Brazil. Decrease in photoperiod and low temperatures (<10˚C) were the determining factors for the induction of growth cessation of the shoots in São Joaquim. The geographic location in a lower latitude and its high altitude results in a distinct growing climate compared to the other winegrowing regions in Brazil.

Consumers’ choices are mainly based on fruit external characteristics such as the final size, weight, and shape. The majority of edible fruit are by tree fruit species, among which peach is the genomic and genetic reference for Prunus. In this research, we used a peach with a slow ripening (SR) phenotype, identified in the Fantasia (FAN) nectarine, associated with misregulation of genes involved in mesocarp identity and showing a reduction of final fruit size. By investigating the ploidy level, we observed a progressive increase in endoreduplication in mesocarp, which occurred in the late phases of FAN fruit development, but not in SR fruit. During fruit growth, we also detected that genes involved in endoreduplication were differentially modulated in FAN compared to SR. The differential transcriptional outputs were consistent with different chromatin states at loci of endoreduplication genes. The impaired expression of genes controlling cell cycle and endocycle as well as those claimed to play a role in fruit tissue identity result in the small final size of SR fruit.

Cell wall turnover and modification in its composition are key factors during stone fruit development and patterning. Changes in cell wall disassembly and reassembly are essential for fruit growth and ripening. Modifications in cell wall composition, resulting in the formation of secondary cell walls, are necessary for producing the most distinctive trait of drupes: the lignified endocarp. The contribution of primary metabolism to cell wall synthesis has been investigated in detail, while the knowledge on the contribution of the cell wall to primary metabolites and related processes is still fragmented. In this review, starting from peculiarities of cell wall of drupes cells (in mesocarp and endocarp layers), we discuss the structure and composition of cell wall, processes related to its modification and contribution to the synthesis of primary metabolites. In particular, our attention has been focused on the ascorbate synthesis cell wall-related and on the potential role of cyanogenic compounds in the deposition of the secondary cell wall.