Current challenges in postharvest biology of fruit ripening

This paper reviews the recent advances in the understanding of the fruit ripening process and describes future challenges. Fruit ripening is a complex developmental process which is orchestrated by the expression of ripening-related genes under the control of a network of signaling pathways. In climacteric fruit components responsible for the production of climacteric ethylene have been identified. Less progress has been made on non-climacteric fruit. Great advances have been made in the characterization of transcription factors (ERFs, RIN, etc...) that induce gene expression through the binding to their promoters. Genetic resources, genome sequencing and “omics” tools have been developed bringing a huge amount of data that will help to draw together an integrative network of regulatory and signaling pathways responsible for triggering and coordinating the ripening process. The discovery that some ripening events are controlled at the epigenetic level and, not in relation with the DNA sequences, opens novel perspectives

Identification of biomarkers associated to ‘Gala’ apples ripening and postharvest quality

Apple is, sociocultural and economically, on of the most important species in the world, and stands out for its high storage potential. However, the monitoring of factors that could result in fruit quality modifications during postharvest is essential to ensure the acceptability and for the development of new storage technologies in order to increase fruit shelf life. Approaches focused on molecular biology, such as RT-qPCR have been used to better understand the mechanisms involved in fruit development and maturation. In this study the use of RT-qPCR to monitoring apple quality during ripening and development in different postharvest conditions such as room temperature, cold storage with or without control of atmosphere and the 1-methylcyclopropene usage were proposed. The potential of genes involved in ethylene biosynthesis and response, cell wall modification and degradation, sugar and aroma metabolisms for employment as biomarkers of fruit development and quality were evaluated. Thus MdEXP4 is highlighted as biomarker for development and MdACO1, MdPG1, MdAF1, MdAF3 and MdAAT2 as potential biomarkers for ripening. MdACO1 and MdPG1 appear as suitable markers for quality, conservation technologies and storage time in apples. This work suggests that the study of gene expression by RT-qPCR may be an alternative for a better fruit characterization during the development and postharvest period.Apple is, sociocultural and economically, on of the most important species in the world, and stands out for its high storage potential. However, the monitoring of factors that could result in fruit quality modifications during postharvest is essential to ensure the acceptability and for the development of new storage technologies in order to increase fruit shelf life. Approaches focused on molecular biology, such as RT-qPCR have been used to better understand the mechanisms involved in fruit development and maturation. In this study the use of RT-qPCR to monitoring apple quality during ripening and development in different postharvest conditions such as room temperature, cold storage with or without control of atmosphere and the 1-methylcyclopropene usage were proposed. The potential of genes involved in ethylene biosynthesis and response, cell wall modification and degradation, sugar and aroma metabolisms for employment as biomarkers of fruit development and quality were evaluated. Thus MdEXP4 is highlighted as biomarker for development and MdACO1, MdPG1, MdAF1, MdAF3 and MdAAT2 as potential biomarkers for ripening. MdACO1 and MdPG1 appear as suitable markers for quality, conservation technologies and storage time in apples. This work suggests that the study of gene expression by RT-qPCR may be an alternative for a better fruit characterization during the development and postharvest period

Transcriptional regulatory networks controlling woolliness in peach in response to preharvest gibberellin application and cold storage

BACKGROUND: Postharvest fruit conservation relies on low temperatures and manipulations of hormone metabolism to maintain sensory properties. Peaches are susceptible to chilling injuries, such as ‘woolliness’ that is caused by juice loss leading to a ‘wooly’ fruit texture. Application of gibberellic acid at the initial stages of pit hardening impairs woolliness incidence, however the mechanisms controlling the response remain unknown. We have employed genome wide transcriptional profiling to investigate the effects of gibberellic acid application and cold storage on harvested peaches. RESULTS: Approximately half of the investigated genes exhibited significant differential expression in response to the treatments. Cellular and developmental process gene ontologies were overrepresented among the differentially regulated genes, whereas sequences in cell death and immune response categories were underrepresented. Gene set enrichment demonstrated a predominant role of cold storage in repressing the transcription of genes associated to cell wall metabolism. In contrast, genes involved in hormone responses exhibited a more complex transcriptional response, indicating an extensive network of crosstalk between hormone signaling and low temperatures. Time course transcriptional analyses demonstrate the large contribution of gene expression regulation on the biochemical changes leading to woolliness in peach. CONCLUSION: Overall, our results provide insights on the mechanisms controlling the complex phenotypes associated to postharvest textural changes in peach and suggest that hormone mediated reprogramming previous to pit hardening affects the onset of chilling injuries. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12870-015-0659-2) contains supplementary material, which is available to authorized users

Genome-wide analysis of the AP2/ERF superfamily in apple and transcriptional evidence of ERF involvement in scab pathogenesis

The APETALA2 (AP2)/ETHYLENE RESPONSE FACTOR (ERF) superfamily of transcriptional regulators is involved in several growth, development and stress responses processes in higher plants. Currently, the available information on the biological roles of AP2/ERF genes is derived from Arabidopsis thaliana. In the present work, we have investigated genomic and transcriptional aspects of AP2/ERF genes in the economically important perennial species, Malus ×domestica. We have identified 259 sequences containing at least one ERF domain in apple genome. The vast majority of the putative proteins display predicted nuclear localization, compatible with a biological role in transcription regulation. The AP2 and ERF families are greatly expanded in apple. Whole-genome analyses in other plant species have identified a single genomic sequence with divergent ERF, whereas in apple seven soloists are present. In the apple genome, the most noteworthy expansion occurred in sub-groups V, VIII and IX of the ERF family. Expression profiling analyses have revealed the association of ripening-involved ERF genes to scab (Venturia inequalis) pathogenesis in the susceptible Gala cultivar, indicating that gene expansion processes were accompanied by functional divergence. The presented analyses of AP2/ERF genes in apple provide evidences of shared ethylene-mediated signaling pathways in ripening and disease responses

Rastreabilidade de pêssegos produzidos no sistema de produção integrada no Sul do Brasil

Traceability is becoming the most effective method to provide a safer food chain and connection producers to consumers. This paper report the application and validation of a traceability system on the production chain of peaches, according the rules for Integrated Production of Peach (IP) and a Hazard Analysis and Critical Control Point (HACCP) systems. The harvesting plots were discriminated using a Global Positioning System (GPS) device. The horticultural practices were registered in a field book according to the Brazilian IP rules. Boxes to transport the fruit, from the orchard on, were barcode labelled to identify the fruits in terms of origin (orchard and harvesting plot), cultivar, quality, picking date and time. Arriving in the factory, by an optical barcode reading device, the fruits in the boxes were assigned to homogeneous batches. Peach cans were labelled according to their corresponding batch number and monitored based on physical and chemical analysis as preconized by the IP rules and HACCP system. An electronic data base was set up and placed over the Internet. Using the batch number, the history of each peaches can could be traceable back to their harvesting plot. Therefore, manufacturers can monitor the product at any time and take any necessary action, such as product recall and/or product reprocessing.A rastreabilidade está se tornando o método mais efetivo para assegurar uma cadeia alimentar mais segura e conectar produtores e consumidores. Nesse trabalho relatamos a aplicação e validação de um sistema de rastreabilidade na cadeia produtiva do pêssego, de acordo com as Normas Brasileiras para Produção Integrada de Pêssego (PIP) e Análises de Perigos e Pontos Críticos de Controle (APPCC). As parcelas de colheita foram discriminadas utilizando-se um aparelho de GPS (Global Positioning System). As práticas horticulturais foram registradas no caderno de campo, de acordo com as normas da PIP. As caixas para transportar as frutas, desde a lavoura, foram etiquetadas com código de barra para identificar as frutas em termos de origem (pomar e parcela de colheita), cultivar, qualidade, data e hora de colheita. Na indústria, utilizando-se um leitor ótico de código de barras, as frutas de cada caixa foram alocadas para um determinado lote homogêneo para fins de processamento. As latas de pêssego foram etiquetadas com o número do lote homogêneo correspondente, foi monitorado com base em análise físicas e químicas, de acordo com as regras da PIP e da APPCC. Uma base d e dados eletrônica foi construída e disponibilizada através da Internet. Utilizando-se o número do lote, foi possível obter todas as informações desde a(s) parcela(s) de colheita correspondente(s) a uma determinada lata de pêssego

QUALIDADE SENSORIAL DE MAÇÃS PRODUZIDAS EM DIFERENTES SISTEMAS DE PRODUÇÃO

The objective was to evaluate the quality sensory of post-harvest apples grown under conventional production systems in transition from conventional-organic, organic and integrated. Cvs apples were harvested. Imperial Gala, Fuji Suprema and Catarina, in commercial orchards in the municipality of São Joaquim / SC in the 2002/03 seasons in four production systems. The fruit were stored in the atmosphere conventional 0 ± 1 ºC and 93 ± 5% RH for 3 months for the ‘Imperial Gala’ and 5 months for the ‘Fuji Suprema’ and ‘Catarina’, followed by 7 days to 15-20 °C. The sensory evaluations were performed at harvest and after of storage. In the joint evaluation of the apples in production systems may arise in a superior visual characteristics of fruit grown in orchards conducted in integrated production systems and organic. In characteristic taste it is superior in fruit grown in organic and integrated system, emphasizing the attributes of acidity, flavor, juiciness and tenderness. The fruits produced in organic and integrated system exhibit superior sensory quality those produced in other production systems.O objetivo deste trabalho foi determinar os efeitos dos sistemas de produção nos atributos de qualidade sensorial, na colheita e após a conservação pós-colheita, de maçãs produzidas em pomares conduzidos em sistemas de produção convencional, em transição convencional-orgânico, integrado e orgânico. Foram colhidas maçãs cvs. Imperial Gala, Fuji Suprema e Catarina, em pomares comerciais no município de São Joaquim/SC na safra de 2002/03, nestes quatro sistemas de produção. As frutas foram armazenadas em atmosfera convencional à 0±1 ºC e 93±5% de UR, por 3 meses para a ‘Imperial Gala’, e 5 meses para a ‘Fuji Suprema’ e ‘Catarina’, seguidos de 7 dias à 15-20 °C.  As avaliações sensoriais foram realizadas na colheita e após armazenamento. Na avaliação conjunta das maçãs nos sistemas de produção pode-se verificar, de modo geral, uma superioridade nas características visuais das frutas produzidas em pomares conduzidos nos sistemas de produção integrado e orgânico. Na característica degustativa, de modo geral, verificou-se superioridade nas frutas produzidas em sistema integrado e orgânico, ressaltados pelos atributos de acidez, sabor, suculência e maciez.  As frutas produzidas no sistema integrado e orgânico apresentam qualidade sensorial superior às frutas produzidas nos demais sistemas de produção

Overexpression of the mitochondrial MT-sHSP23.6 gene during antioxidant activity in tomato cv. Micro-Tom subjected to flooding

Plants grown under flooding stress conditions form reactive oxygen species, both during oxygen deficiency and after reoxygenation. The tolerance of plants under these conditions depends on an efficient antioxidant system, which may be influenced by the higher expression of heat shock proteins, such as mitochondrial MT-sHSP23.6. The objective of the present study was to determine whether the overexpression of this gene increases the antioxidant activity in tomato cv. Micro-Tom plants subjected to flooding during the vegetative stage of four fully expanded leaves. The experiment was performed with three genotypes of tomato plants (Solanum lycopersicum Mill. cv. Micro-Tom), one non-transformed denominated “WT” and two modified for high and low expression of the MT-sHSP23.6 gene, subjected to normal irrigation conditions, 72 hours of flooding, and 24 and 192 hours of recovery after the removal of flooding, consisting a 3x4 split-plot factorial design with four replications. Plants were collected at the vegetative stage of 4 fully expanded leaves to determine superoxide dismutase, ascorbate peroxidase and catalase activities, hydrogen peroxide accumulation and lipid peroxidation. Overexpression of the mitochondrial MT-sHSP23.6 gene in the evaluated plants resulted in higher antioxidant system activity. However, it did not necessarily lead to less damage caused by oxidative stress. Low expression of this gene resulted in lower antioxidant system activity and greater damage caused by reactive oxygen species

Produção e qualidade de frutos de minimelancia com diferentes números de hastes, em sistema de cultivo em calhas e reutilização de substrato

Substrate-filled pots are growing systems commonly used for vegetable farming. However, few are the studies available relating them to mini-watermelon cultivation. Our study presents a growing system using substrate-filled troughs and leachate recirculation as a low-cost and less environmentally harmful soilless cultivation system for mini-watermelons. For a growing system to be viable and provide high fruit yield and quality, several aspects must be studied, including substrate physical properties and reuse potential in successive crops, besides plant management-related aspects. Therefore, our goal was to evaluate the effects of a trough system and substrate reuse on changes in the properties of raw rice husk and on fruit yield and quality for mini-watermelons at different stem training. To this purpose, two trials were conducted using nutrient solution recirculation systems. In the first, we evaluated the effects of pot and trough systems. In the second, first- and second-use substrates were compared in the trough system. In both trials, one and two-stem training systems were analyzed. The results of the first trial show that the trough system had a greater positive impact on substrate water holding capacity (WHC), which increased from 7.9 to 15.6%, while the pots increased substrate WHC only to 11.2%. However, both systems neither affected fruit yield (8 kg/m2 on average) nor fruit quality. The two-stem training promoted higher fruit yields (4.2 kg/plant) and contents of total soluble solids - TSS (11.4 oBrix) but did not affect average fruit weight. Moreover, the one-stem training provided higher fruit number (7.3 fruits/m2) and fruit yield (9.7 kg/m2). In the second trial, the reused substrate showed a higher WHC (12.4%) than the one used for the first time (9.9%). The reused substrate also provided better results in terms of fruit yield and quality (5.9 fruits/m2, 5.3 kg/m2, and 10.5 oBrix). In the second trial, two-stem training also increased average fruit weight, and hence yields per plant. Nevertheless, the stem number did not affect fruit number per plant, fruit yield per square meter, and fruit quality.O cultivo em vasos com substrato é uma técnica em expansão na produção de hortaliças, porém, para minimelancias, poucos estudos estão disponíveis. Este trabalho introduz o sistema de calhas preenchidas com substrato e com recirculação do lixiviado para esta cultura, como uma alternativa de baixo custo e menor impacto ambiental. Para que o sistema seja viável e possibilite boa produtividade e qualidade dos frutos, vários aspectos devem ser estudados, entre estes, as características físicas do substrato, a possibilidade de reutilizá-lo em cultivos sucessivos e o manejo adequado das plantas. O objetivo do trabalho foi estudar o efeito do sistema de cultivo e da reutilização sobre as alterações das propriedades do substrato de casca de arroz in natura, a produção e a qualidade de frutos de plantas de minimelancia cultivadas com diferentes números de hastes. Dois experimentos, empregando sistemas com recirculação da solução nutritiva, foram realizados. No primeiro, as plantas foram cultivadas em vasos e calhas. No segundo, foram comparados substratos de primeiro e segundo uso no cultivo em calhas. Em ambos os experimentos, foi estudada a condução das plantas em uma e duas hastes. Em relação aos resultados obtidos, no primeiro experimento, o sistema de calhas teve maior impacto positivo sobre as características físicas do substrato, cuja capacidade de retenção de água (CRA) passou do valor inicial de 7,9% para 15,6% ao final, enquanto que nos vasos se elevou a 11,2%. Porém, os sistemas não afetaram a produtividade, com média de 8 kg/ m2, e a qualidade dos frutos. As plantas de duas hastes apresentaram maior produção de frutos (4,2 kg/ planta), com maior conteúdo de sólidos solúveis totais - SST (11,4 oBrix), ainda que sem efeito sobre o peso médio. Porém, as plantas de uma haste apresentaram maior número (7,3 frutos/m2) e produção de frutos (9,7 kg/m2). No segundo experimento, o substrato de 2o uso apresentou maior CRA (12,4%) que o substrato novo (9,9%) e proporcionou melhores resultados de produtividade e qualidade para a maioria das variáveis estudadas, obtendo-se 5,9 frutos e 5,3 kg/m2, com SST de 10,5 oBrix. As plantas de duas hastes tiveram resultados melhores de peso médio de frutos e, consequentemente, de produção por planta do que as plantas de uma haste, sem efeitos sobre o número de frutos/planta, o rendimento por m2 e a qualidade

Produtividade e qualidade de caqui na colheita e após armazenamento refrigerado com aplicação de diferentes doses de nitrogênio no solo

Com o objetivo de avaliar as respostas de caquizeiros “Fuyu” submetidos a diferentes doses de nitrogênio (N), relacionados a aspectos produtivos e de qualidade pós-colheita, durante as safras 2007, 2008 e 2009 em um pomar comercial adulto, localizado no município de Rio das Antas, SC, foi aplicado 0 – 30 – 60 – 120 – 180 kg.ha-1 de N. Na pré-colheita determinou-se o número de frutos por planta, o índice de queda prematura de frutos, a produtividade e a porcentagem de frutos moles por ocasião da colheita. Os frutos foram colhidos quando se encontravam no ponto de maturação comercial e as amostras a serem armazenadas foram expostas ao 1-MCP, embaladas em bolsa de polietileno e armazenadas 45 dias a 0±0,8 ºC e umidade relativa de 77±7%. As análises foram feitas logo após a colheita e sete dias depois do período de armazenagem refrigerada, em que se mensurou a coloração da casca, a firmeza de polpa, o teor de sólidos solúveis totais, a firmeza subjetiva, a incidência de estrias, translucidez, podridões, pintas pretas grandes  e pintas pretas pequenas. Adicionalmente foi realizada a análise mineral da polpa e da folha. A aplicação de N proporcionou aumento do número de frutos recém-formados e da produtividade e também influenciou na qualidade destes.Palavras-chave: Escurecimento. Distúrbios fisiológicos. Nitrogênio. Firmeza. Adubação.