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Exocarp color de-synchronization with softening of 'Hass' avocado is a relevant recurrent problem for the avocado supply chain. This study aimed to unravel the mechanisms driving this de-synchronization integrating omics datasets from avocado exocarp of different storage conditions and color phenotypes. In addition, we propose potential biomarkers to predict color synchronized/de-synchronized fruit. Integration of transcriptomics, proteomics and metabolomics and network analysis revealed eight transcription factors associated with differentially regulated genes between regular air (RA) and controlled atmosphere (CA) and twelve transcription factors related to avocado fruit color de-synchronization control in ready-to-eat stage. CA was positively correlated to auxins, ethylene, cytokinins and brassinosteroids-related genes, while RA was characterized by enrichment of cell wall remodeling and abscisic acid content associated genes. At ready-to-eat higher contents of flavonoids, abscisic acid and brassinosteroids were associated with color-softening synchronized avocados. In contrast, de-synchronized fruit revealed increases of jasmonic acid, salicylic acid and auxin levels.

Ripening heterogeneity of Hass avocados results in inconsistent quality fruit delivered to the triggered and ready to eat markets. This research aimed to understand the effect of a heat shock (HS) prior to controlled atmosphere (CA) storage on the reduction of ripening heterogeneity. HS prior to CA storage reduces more drastically the ripening heterogeneity in middle season fruit. Via correlation network analysis we show the different metabolomics networks between HS and CA. High throughput proteomics revealed 135 differentially expressed proteins unique to middle season fruit triggered by HS. Further integration of metabolomics and proteomics data revealed that HS reduced the glycolytic throughput and induced protein degradation to deliver energy for the alternative ripening pathways. l-isoleucine, l-valine, l-aspartic and ubiquitin carboxyl-terminal hydrolase involved in protein degradation were positively correlated to HS samples. Our study provides new insights into the effectiveness of HS in synchronizing ripening of Hass avocados.

Tissue texture influences the grape berry consumers acceptance. We studied the biological differences between the inner and outer mesocarp tissues in hard and soft berries of table grapes cv NN107. Texture analysis revealed lower levels of firmness in the inner mesocarp as compared with the outer tissue. HPAEC-PAD analysis showed an increased abundance of cell wall monosaccharides in the inner mesocarp of harder berries at harvest. Immunohistochemical analysis displayed differences in homogalacturonan methylesterification and cell wall calcium between soft and hard berries. This last finding correlated with a differential abundance of calcium measured in the alcohol-insoluble residues (AIR) of the inner tissue of the hard berries. Analysis of abundance of polar metabolites suggested changes in cell wall carbon supply precursors, providing new clues in the identification of the biochemical factors that define the texture of the mesocarp of grape berries.

Pseudomonas orientalis and Chaetomium cupreum isolated from metal(oid)s-contaminated soil were characterized to evaluate their role in plant growth promotion and enhance the tolerance of Eucalyptus globulus to copper stress. We evaluated minimum inhibitory concentration and explored plant-promoting traits under copper stress. Moreover, changes in morphology and the accumulation of metals on the cell surface were determined by scanning electron microscopy images coupled with energy dispersive x-ray spectroscopy (SEM-EDX). The effect of inoculation with P. orientalis and C. cupreum on E. globulus plants established in soils contaminated with copper was determined through root and shoot biomass and antioxidant response. Both strains showed high tolerance to metal(oid)s, whereas phosphate solubilization was only detected in P. orientalis. Under copper stress, C. cupreum presented a higher production rate of siderophores and indole acetic acid (4.5 mm day−1, 15.042 μg mL−1). SEM images and EDX analysis reflected cellular changes in fungus and proved biosorption of copper. Inoculation of P. orientalis and C. cupreum on Eucalyptus globulus plants significantly increased plant growth and mitigated the toxic effects of copper. According to these results, both microorganisms contribute positively to stimulated plant growth and to decreasing stress caused by high concentrations of copper in soil, especially C. cupreum.

Chile is the third largest exporter of kiwifruit in the world. Its varietal production has traditionally been focused on green-fleshed kiwifruit varieties, with ‘Hayward’ being the most exported variety. ‘Soreli’ is a new Italian kiwifruit variety, which is characterized by its early ripening, big size, sweet taste, as well as its yellow flesh. This gives ‘Soreli’ a good opportunity to promote the consumption of yellow-fleshed varieties, and a wider assortment of kiwifruit in the market. The aim of this work is to evaluate postharvest traits and consumer acceptance in kiwifruit var. ‘Soreli’, with a combination of storage temperatures of 0 °C and 20 °C and 1-methylcyclopropene (1-MCP) applications. Cold storage and 1-MCP treatments caused a positive response in kiwifruit var. 'Soreli'. In the case of fruits stored at 20 °C, 1-MCP treatment extended the postharvest life of the fruits at least 3 weeks while the fruits stored in cold at 0 °C treated with 1-MCP reached 8 weeks. In general, the respiration rate was higher in the control treatments with respect to the 1-MCP treatments, as well as the ethylene emission occurred earlier in the control. In addition, the kiwifruit sensory quality attributes were adequate in all cases, reaching a medium or high acceptability in the evaluation panel.

Firm berries are highly appreciated by table grape consumers. Cell wall composition is one of the main factors influencing the firmness of table grape berries. Nevertheless, the biological factors driving changes in berry firmness remain unclear. In the present work, we evaluated the firmness of berries of Vitis vinifera cv. Thompson Seedless. We selected two orchards displaying contrasting berry firmness and evaluated polar metabolites and cell wall composition. Our results suggest that berries from the soft orchard exhibited a higher accumulation of sugars at veraison whereas berries from the hard orchard accumulated the same sugars at harvest plus a higher amount of glucose monosaccharide at the cell wall. Thus, this study opens new insights about a connection between metabolic and cell wall changes with fruit firmness in a table grape variety, suggesting that it is possible to use metabolomic tools to identify metabolic biomarkers associated with table grape berry firmness.

Chilling injury represents a major constrain for crops productivity. Prunus persica, one of the most relevant rosacea crops, have early season varieties that are resistant to chilling injury, in contrast to late season varieties, which display chilling symptoms such as mealiness (dry, sandy fruit mesocarp) after prolonged storage at chilling temperatures. To uncover the molecular processes related to the ability of early varieties to withstand mealiness, postharvest and genome-wide RNA-seq assessments were performed in two early and two late varieties. Differences in juice content and ethylene biosynthesis were detected among early and late season fruits that became mealy after exposed to prolonged chilling. Principal component and data distribution analysis revealed that cold-stored late variety fruit displayed an exacerbated and unique transcriptome profile when compared to any other postharvest condition. A differential expression analysis performed using an empirical Bayes mixture modeling approach followed by co-expression and functional enrichment analysis uncover processes related to ethylene, lipids, cell wall, carotenoids and DNA metabolism, light response, and plastid homeostasis associated to the susceptibility or resistance of P. persica varieties to chilling stress. Several of the genes related to these processes are in quantitative trait loci (QTL) associated to mealiness in P. persica. Together, these analyses exemplify how P. persica can be used as a model for studying chilling stress in plants.

Kiwifruit bleeding sap samples, collected in Italian and Chilean orchards from symptomatic and asymptomatic plants, were evaluated for the presence of Pseudomonas syringae pv. actinidiae, the causal agent of bacterial canker. The saps were sampled during the spring in both hemispheres, before the bud sprouting, during the optimal time window for the collection of an adequate volume of sample for the early detection of the pathogen, preliminarily by molecular assays, and then through its direct isolation and identification. The results of molecular analyses showed more effectiveness in the P. syringae pv. actinidiae detection when compared with those of microbiological analyses through the pathogen isolation on the nutritive and semiselective media selected. The bleeding sap analyses allowed the isolation and identification of two hypersensitive response (HR) negative and hypovirulent P. syringae pv. actinidiae strains from different regions in Italy. Moreover, multilocus sequence analysis (MLSA) and whole genome sequence (WGS) were carried out on selected Italian and Chilean P. syringae pv. actinidiae virulent strains to verify the presence of genetic variability compared with the HR negative strains and to compare the variability of selected gene clusters between strains isolated in both countries. All the strains showed the lack of argK and coronatine gene clusters as reported for the biovar 3 P. syringae pv. actinidiae strains. Despite the biologic differences obtained in the tobacco bioassays and in pathogenicity assays, the MLSA and WGS analyses did not show significant differences between the WGS of the HR negative and HR positive strains; the difference, on the other hand, between PAC_ICE sequences of Italian and Chilean P. syringae pv. actinidiae strains was confirmed. The inability of the hypovirulent strains IPV-BO 8893 and IPV-BO 9286 to provoke HR in tobacco and the low virulence shown in this host could not be associated with mutations or recombinations in T3SS island.

Hass avocado ripening heterogeneity generates logistics problems to importers and ripeners due to higher labour costs, inconsistent quality delivery and postharvest losses. The main aims of this research were: (i) to evaluate two postharvest pre-treatments (nitrogen shock N 2 and heat shock) prior controlled atmosphere (CA) on reduction of ripening heterogeneity of Hass avocado without being detrimental to fatty acid profile and (ii) to study the potential metabolic processes implicated in such ripening synchronization with focus on cell wall remodelling and ethylene biosynthetic pathways. Results showed that heat shock prior to CA storage significantly reduced ripening heterogeneity in early and middle season fruit while N 2 + CA did not. Pectin methyl esterase (PME) and polygalacturonase (PG) activity did not display significant differences among treatments. Additionally, none of the treatments altered the fatty acid profile. ACS transcript for early and middle season fruit kept constant during storage for heat + CA, CA and N 2 + CA. ACO instead displayed less abundance after 21 d storage for all treatments of early season fruit. These results point to ripening synchronization in Hass avocado subjected to heat to be related to induction of metabolic processes related to ethylene (biosynthesis), possibly at the action level (receptors) but the efficiency of the heat treatment was related to the maturity stage of the batch.

Peach is the third most important temperate fruit crop considering fruit production and harvested area in the world. Exporting peaches represents a challenge due to the long-distance export markets. This requires fruit to be placed in cold storage for a long time, which can induce a physiological disorder known as chilling injury (CI). The main symptom of CI is mealiness which is perceived as non-juicy fruit by consumers. The purpose of this work was to identify and compare the metabolic and lipid profile between two siblings from a contrasting population for juice content, at harvest and after 30 days at 0°C. A total of 119 metabolites and 189 lipids were identified, which showed significant differences of abundance including mainly in amino acids, sugars and lipids. Our results indicate that some of the top metabolites and lipids could be used as biomarkers associated with mealiness at harvest and after cold storage.

The cherimoya (Annona cherimola Mill.) is an exotic climacteric fruit with interesting organoleptic traits, such as intense aroma and flavor, but it is highly perishable and susceptible to cut surface browning. The use of cherimoya is mainly for fresh consumption, although some studies aimed at producing fresh-cut products have been carried out. The postharvest life of the cherimoya mainly depends on appropriate handling during storage, avoiding chilling conditions, preventing mechanical damage, and maintaining a short transportation period to reduce loss of quality. Controlled and modified atmospheres, and ethylene action inhibitors have been used to slow ripening, reduce senescence, and maintain fruit quality, but the results, although promising, are mainly experimental.

Surface pitting is a serious postharvest physiological disorder in sweet cherries that is observed as skin depressions developed days after bruising. This work aims to compare two cultivars displaying different pitting susceptibilities ('Kordia': relatively resistant; 'Sweetheart': relatively susceptible) using metabolomics profiling and cell wall sugar characterization at different developmental stages and during postharvest storage. Kordia was significantly firmer than Sweetheart, with 1.4-fold more alcohol-insoluble residues (AIRs). A significant correlation was observed between AIRs and deformation, indicating that the highest yields of cell wall material are positively correlated with the resistance to rupture. Additionally, free d-galacturonic acid was higher in pitted Sweetheart samples, likely indicating greater pectin degradation in this susceptible cultivar. Higher contents of the p-coumaric acid derivatives L-5-oxoproline and d-galactose in Sweetheart cherries were found. The metabolic changes during storage and cell wall composition could influence the susceptibility to surface pitting.

One important physiological disorder in sweet cherry (Prunus avium L.) is surface pitting. This disorder involves irregular depressions on the fruit surface and occurs during harvest, but it develops during cold storage. The aim of this research was to understand the phenotypic characteristics and biochemical responses, referring to the metabolomic profile and the composition and disassembly of the cell wall, that underlie the susceptibility to pitting. The study was carried out using cultivars with contrasting pitting behaviors, such as Bing (resistant) and Sweetheart (sensitive), during ripening and postharvest storage. Induced pitting did not have a negative impact on quality parameters except visual quality in sweet cherries during cold storage, and firmness was not a key parameter that explained the susceptibility to pitting. The mechanical stress to induce pitting triggered a significant decline in pectin methylesterase (PME) activity on day 14 of storage for the Sweetheart cultivar. Intensified labeling for methylated homogalacturonan immunostaining of pitted mesocarp cells in Bing was observed. Xyloglucan showed more abundant labeling in pitted samples, which was more pronounced in Sweetheart fruit than Bing cherries. The metabolomic screening showed a higher content of organic acids and amino acids in the Sweetheart cultivar, while the Bing cultivar had higher contents of sorbitol and arabinitol. Proline and 2-oxoglutaric acid emerged as metabolites altered in response to mechanical stress in both cultivars. Furthermore, pitted Bing fruit elicits anthocyanin overexpression. The metabolomic analysis suggests that susceptibility to pitting could depend on the metabolic differences of each cultivar because the induced pitting did not greatly disrupt the studied metabolic responses.

The aim of this study was to model Chilean “Hass” avocado softening behaviour, destined to local and distant markets, taking into account the biological variation given by growing location and harvest stages. A total of 24 batches were obtained during the season 2018–2019 from different agro-climatic zones (coast, intermediate and interior) and two harvest stages (based on dry matter content). Fruit softening during either regular air (RA) or controlled atmosphere (CA) storage at 5 °C followed by shelf-life at 20 °C was modelled using a simplified mechanistic model. Most of the model parameters were treated as being generic for all fruit except for two fruit specific parameters, F0 (firmness at harvest) and E0 (amount of enzyme complex at harvest) that characterized the fruit at harvest and thus postharvest ripening behaviour. The model was able to describe 87.6 % of the observed variation of all 24 fruit batches studied from different agro-climatic zones at the batch averaged level, but 93.5 % of the observed variation at the fruit individual level. Since measured at harvest when most fruit are highly firm, initial fruit firmness by itself was not able to discriminate among the various batches as they all showed similar normal distributions among the different agro-climatic zones, in addition, the estimated E0 values for each individual fruit were correlated to key metabolites to identify potential metabolite biomarkers discriminating among the different regions and batches. The developed model can be utilized to predict the batch specific ripening behaviour of “Hass” avocado under different postharvest logistic chains given the distribution of E0 is known.

Rachis browning corresponds to a postharvest disorder that drastically reduces overall table grape quality. This problem has been associated mainly to water loss, but the possibility of having other factors involved like green pigment degradation and brownish compound synthesis that mask the green tissue is also feasible. Modified Atmosphere Packaging (MAP) is a technology used to extend table grape postharvest life, including rachis appearance. The objective of this study was to analyze the effects caused by MAP on rachis browning during cold storage of ‘Red Globe’ table grape variety. MAP helped to reduce the green color loss on rachises stored for 90 days of storage at 0 °C compared with a conventional storage (CS) even after a shelf life period, without to affect negatively the quality of the berries. Interestingly, MAP storage decreased the content of chlorophyll- a and increased the amount of pheophytin- a, a chlorophyll degradation product, compared to CS both after cold storage period and shelf life. Additionally, the expression of genes involved in the chlorophyll breakdown pathway was analyzed by qPCR. We found that MAP induced an increase in the transcript abundance of metal-chelating substance ( MCS ) and Red Chlorophyll Catabolite Reductase ( RCCR ) genes. However, Pheophytinase ( PPH ) and Pheophorbide-a Oxigenase ( PaO ) transcript accumulation revealed no changes compared with CS. Apparently, MAP generated a modification in the chlorophyll breakdown process allowing an accumulation of green like compounds responsible for the greener color of rachises in the MAP stored bunches. On the other hand, histological analysis reveals that after cold storage and shelf life, morphological changes and brown compounds accumulation take place at the periderm and cortex tissues, and these symptoms are less severe in MAP stored bunches helping to keep longer the green coloration of the rachises. In this study we observed that MAP storage increases rachis postharvest quality by reducing green color loss probably due to a combination of processes involving a delay of green pigments degradation and a less accumulation of brown compounds at the periderm and cortex tissues, thus preventing green pigments masking.

Indexación: Web of Science Introduction. 'Hass' is the main avocado cultivar commercialized worldwide. The extended flowering period, very low percentage of fruit set and inability to ripen on the tree renders the fruit heterogeneous and unpredictable during postharvest management. The "triggered" and "ready-to-eat" growing markets for 'Hass' avocados are affected by the variable postharvest ripening or ripening heterogeneity which creates severe logistical problems for marketers and inconsistent quality delivery to consumers. Synthesis. The dry matter content, the current avocado harvest index that correlates very well with oil content, has been extensively used to harvest 'Hass' avocados to comply with the minimum standards to guarantee consumer satisfaction. However, previous work and empirical experience demonstrate that dry matter does not correlate on a fruit-to-fruit basis with time to reach edible ripeness. Thus, avocados of very different ages are harvested from individual trees, resulting in heterogeneous postharvest ripening of fruit within a specific batch. Several preharvest factors related to environmental and growing conditions and crop management as well as postharvest technology strategies influence the observed variability of postharvest ripening. Conclusion. Modern approaches based on studying the composition of individual fruits displaying contrasting postharvest ripening behavior, combined with non-destructive phenotyping techniques, seem to offer practical solutions for the fresh supply chain of avocados to sort fruit based on their ripening capacity. http://www.pubhort.org/fruits/2016/5/fruits160045.htm

The aroma in avocados (Persea americana Mill. cv. ‘Hass’) is mainly defined by fatty acids-derived volatile compounds that change according to the fruit maturity stage which is modulated by ethylene. In order to understand the changes in fatty acid substrates and gene expression involved in the synthesis of the key aroma-volatile compounds in avocado after harvest, we performed two trials using avocados harvested with 11% oil content. In the first trial avocados were ripened immediately after harvest at 20 °C until reaching the ready-to-eat stage, and in the second trial, fruit were stored at 5 °C for 30 days and then ripened at 20 °C. In addition, to assess the ethylene effect in the volatile compounds and transcript levels measured, a 100 μl L−1 ethylene application was carried out, at harvest or after storage for trial 1 and 2, respectively. The concentration of the key volatile compounds and fatty acids were performed by gas chromatography, and the changes in the expression of genes related to lipoxygenase derived compounds were measured by q-PCR. The results obtained indicated that ethylene modulated the production of linolenic acid and hexanal, whereas at the gene expression level, only PamLOX transcript changes responded to ethylene application, although its changes were maturity/ripening dependent. The cold storage did not generate significant changes in fatty acids and gene expression levels, but a decreased in the concentration of hexanal during the ripening was observed.

Avocado (Persea americana Mill) is rich in a variety of essential nutrients and phytochemicals; thus, consumption has drastically increased in the last 10 years. Avocado unlike other fruit is characterized by oil accumulation during growth and development and presents a unique carbohydrate pattern. There are few previous and current studies related to primary metabolism. The fruit is also quite unique since it contains large amounts of C7 sugars (mannoheptulose and perseitol) acting as transportable and storage sugars and as potential regulators of fruit ripening. These C7 sugars play a central role during fruit growth and development, but still confirmation is needed regarding the biosynthetic routes and the physiological function during growth and development of avocado fruit. Relatively recent transcriptome studies on avocado mesocarp during development and ripening have revealed that most of the oil is synthesized during early stages of development and that oil synthesis is halted when the fruit is harvested (pre-climacteric stage). Most of the oil is accumulated in the form of triacylglycerol (TAG) representing 60-70% in dry basis of the mesocarp tissue. During early stages of fruit development, high expression of transcripts related to fatty acid and TAG biosynthesis has been reported and downregulation of same genes in more advanced stages but without cessation of the process until harvest. The increased expression of fatty acid key genes and regulators such as PaWRI1, PaACP4-2, and PapPK-β-1 has also been reported to be consistent with the total fatty acid increase and fatty acid composition during avocado fruit development. During postharvest, there is minimal change in the fatty acid composition of the fruit. Almost inexistent information regarding the role of organic acid and amino acid metabolism during growth, development, and ripening of avocado is available. Cell wall metabolism understanding in avocado, even though crucial in terms of fruit quality, still presents severe gaps regarding the interactions between cell wall remodeling, fruit development, and postharvest modifications.

Background Avocado (Persea americana Mill.) is a basal angiosperm from the Lauraceae family. This species has a diploid genome with an approximated size of ~ 920 Mbp and produces a climacteric, fleshy and oily fruit. The flowering and fruit set are particularly prolonged processes, lasting between one to three months, generating important differences in physiological ages of the fruit within the same tree. So far there is no detailed genomic information regarding this species, being the cultivar ‘Hass’ especially important for avocado growers worldwide. With the aim to explore the fruit avocado transcriptome and to identify candidate biomarkers to monitore fruit development, we carried out an RNA-Seq approach during 4 stages of ‘Hass’ fruit development: 150 days after fruit set (DAFS), 240 DAFS, 300 DAFS (harvest) and 390 DAFS (late-harvest). Results The ‘Hass’ de novo transcriptome contains 62,203 contigs (x̅=988 bp, N50 = 1050 bp). We found approximately an 85 and 99% of complete ultra-conserved genes in eukaryote and plantae database using BUSCO (Benchmarking Universal Single-Copy Orthologs) and CEGMA (Core Eukaryotic Gene Mapping Approach), respectively. Annotation was performed with BLASTx, resulting in a 58% of annotated contigs (90% of differentially expressed genes were annotated). Differentially expressed genes analysis (DEG; with False Discovery Rate ≤ 0.01) found 8672 genes considering all developmental stages. From this analysis, genes were clustered according to their expression pattern and 1209 genes show correlation with the four developmental stages. Conclusions Candidate genes are proposed as possible biomarkers for monitoring the development of the ‘Hass’ avocado fruit associated with lipid metabolism, ethylene signaling pathway, auxin signaling pathway, and components of the cell wall. Electronic supplementary material The online version of this article (10.1186/s12864-019-5486-7) contains supplementary material, which is available to authorized users.

Peach (Prunus persica) is one of the most important temperate fruit trees in the world, based on its production and cultivated area. Consumer acceptance is the principal objective of multiple breeding programs and it is dependent on many factors. Among these factors, an important role is played by the soluble solids content (SSC) and the postharvest performance represented by mealiness (M) susceptibility as a chilling injury disorder. Additionally, a major maturity date (MD) QTL has been reported to have a pleiotropic effect on both M and SSC. The aim of this work was QTL identification of SSC, MD, and M and to identify adequate candidate genes that are linked to regulation of these traits. The analysis was performed by evaluation of fruit quality traits during three consecutive seasons in an F1 progeny of 194 siblings, which were obtained from the intraspecific cross between the yellow-flesh peach “O’Henry” and the white-flesh nectarine NR-053. The main result was the construction of a genetic linkage map with 499 markers (486 SNPs, 11 SSRs, and two morphological markers) spanning 717.6 cM, with an average distance between markers of 1.5 cM/cluster. The analysis allowed the identification of consistent QTLs for SSC and M in the linkage group LG5 and for MD in LG1, LG2, LG5, and LG6. A large number of genes were annotated in QTL intervals, which was reduced by selecting the genes with at least one SNP, which caused an amino acid variation. For SSC, the data identified four transcription factors, one gene involved directly with the sugar accumulation process, and one cell wall remodeling-related gene. For MD, 23 cell wall-related genes, three jasmonic acid-linked genes, eight transcription factors, and one ripening-related gene were identified. Finally, only one cell wall gene was identified that was associated with M. In conclusion, these results improve our understanding of the genetic control of fruit quality traits with commercial relevance in P. persica and specifically in the O × N mapping population., This work was supported by Fondo Nacional de Desarrollo Científico y Tecnológico FONDECYT-CHILE1160584, Fondo de Fomento al Desarrollo Científico y Tecnológico FONDEF-CHILED13i10005 and Corporación de Fomento de la Producción CORFO-CHILE Biofrutales13CTI21520-SP04.

Animals raised in backyard productive systems (BPS) have been frequently associated with Salmonella outbreaks. Several serovars have caused these events, showing that different BPSs can be contaminated by distinct Salmonella serovars. The aim of this study was to characterize the genomic diversity of Salmonella isolates obtained from BPSs in Central Chile to understand their genomic relatedness. A whole-genome SNP-based phylogenetic analysis of 22 Salmonella isolates from 12 locations revealed that S. Typhimurium isolates clustered based on the BPS that they were originally isolated from, and the same was established for S. Enteritidis isolates. Furthermore, our genomic analysis shows that animals from different species (i.e., a chicken, a duck and a pig) carried genetically related S. Typhimurium strains within the same BPS. Moreover, some of these genetically related isolates were obtained in different years (2013 and 2014), indicating that farm-specific Salmonella can persist in BPSs for multiple years and that interspecies transmission is plausible in this environment. Understanding the dynamics of interspecies transmission of Salmonella serovars within a contaminated BPS is fundamental to the design of mitigation strategies to reduce outbreaks of human Salmonella associated with backyard production systems.

Berry firmness is one of the most important quality traits in table grape production and, consequently, a key aspect for table grape breeding programs. To identify the genes determining the berry firmness in grapes, a progeny of Ruby Seedless × Sultanina (n = 137) was evaluated during three consecutive seasons. Results showed that even though the heritability was ~90%, season had an important effect on this trait. Quantitative trait loci (QTL) analysis and genetic mapping showed that the determinants for this trait are distributed in linkage groups 8 and 18. This is the first time that a stable QTL for berry firmness across seasons has been identified on linkage group 8. This QTL is mainly given by a male allelic and additive effect. Together, these two QTLs explained ~27.6% of the phenotypic variance, with confidence intervals of up to 10 cM. Among the tens of genes found in these two QTLs, we highlight a cation/calcium exchanger, a xylosyltransferase, a probable cellulose synthase, and a putative invertase. This study shows that berry firmness has a clear genetic basis. These results could also be used for the development of markers to assist table grape breeding.

Peaches are stored at low temperatures to delay ripening and increase postharvest life. However some varieties are susceptible to chilling injury,which leads to fruit mealiness, browning and flesh bleeding. In order to identify potentialmarkers associated with chilling injury,we performed proteomic analyses on a segregating population with contrasting susceptibility to chilling-induced mealiness. Chilling-induced mealiness was assessed by measuring juiciness in fruits that have been stored in cold and then allowed to ripen. Fruitmesocarp and leaf proteome from contrasting segregants were analyzed using 2-DE gels. Comparison of protein abundance between segregants revealed 133 spots from fruit mesocarp and 36 from leaf. Thirty four fruit mesocarp proteins were identified from these spots. Most of these proteins were related to ethylene synthesis, ABA response and stress response. Leaf protein analyses identified 22 proteins, most of which related to energy metabolism. Some of the genes that code for these proteins have been previously correlated with chilling injury through transcript analyses and co-segregation with mealiness QTLs. The results from this study, further deciphers the molecular mechanisms associated with chilling response in peach fruit, and identifies candidate proteins linked to mealiness in peach which may be used as putative markers for this trait.