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 subgroups 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.

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In order to understand early molecular events associated with increase in fruit size and woolliness prevention induced by pre-harvest gibberellic acid (GA 3 ) spraying, differential transcript accumulation of genes encoding proteins putatively involved in protein folding and protection, cell wall metabolism, and endomembrane transport was studied during fruit development of 'Chiripá' peach. Woolliness occurrence reached 100% in untreated peach, was reduced by 15% with GA 3 spraying at the end of the pit hardening stage and was significantly reduced (by 78%) in peaches treated at the beginning of the pit hardening stage despite a significantly increased fruit size. Low incidence of woolliness after cold storage and fruit size increase in early GA 3 treated peach was correlated with high transcript accumulation of genes encoding proteins putatively involved in protein folding, and protection of the endoplasmic reticulum (heat shock proteins-HSP40 er) and chloroplast (HSP17.8 ch), endomembrane transport (GTPase), as well as genes involved in cell wall loosening (expansins-Exp1, Exp2, Exp3, Exp4).

Uma das principais alterações fenotípicas facilmente perceptíveis após a colheita de brócolis é o amarelecimento, decorrente da aceleração do metabolismo, induzida pelo etileno (KAWAMAKI;WATANABE, 1988). Além de prejudicar a aparência, reduzindo o valor comercial, tem-se observado que, quanto maior a velocidade e a intensidade com que o amarelecimento ocorre, maiores são as perdas nutricionais e das propriedades funcionais dessa hortaliça (JONES et al., 2006;MORENO et al., 2006). É conhecido que o metabolismo pós-colheita de brócolis é caracterizado pelo incremento da produção de etileno e da taxa respiratória, e que a adoção de práticas que controlem essas vias metabólicas podem estender a vida-de-prateleira (ABLE et al., 2003; WILLS, 1987). Assim, por exemplo, a redução da temperatura (SALVEIT, 1999), o controle das concentrações de O 2 e de CO 2 na atmosfera (KADER et al., 1989), e/ou a aplicação de 1-metilciclopropeno (1-MCP) (ABLE et al., 2003;WILLS, 1999;WILLS et al., 2002), podem melhorar a conservabilidade dos brócolis.Não obstante esses avanços, a preservação da coloração esverdeada em brócolis ainda é um desafio. As respostas à aplicação desses métodos de conservação (refrigeração, atmosfera modificada e controlada, e aplicação de 1-MCP) têm sido variadas entre cultivares e para a mesma cultivar produzida em condições edafoclimatológicas distintas, conforme previamente relatado por Wurr et al. (2002). Essa problemática tem sido citada sistematicamente pelos produtores da Região Sul do Brasil. AbstractEthylene increases the post-harvest metabolism of broccoli. The ethylene synthesis might be inducted by mechanical injury and temperature decrease. Therefore, 3 experiments were carried out to assess these hypotheses: 1) it was evaluated the mechanical injury effect on the ethylene production; 2) the effect of cold storage; and 3) effect of the 1-MCP on the broccoli metabolism and conservation. The results showed that the mechanical injury increased the ethylene production, from 0,25 to 501,83 mL.h -1 g -1, two hours after the injury occurrence. In contrast, in the control treatment the increments were lower, varying from 0,27 to 203,13 mL.h -1 g -1. During storage, the deterioration occurred more rapidly in the control treatment (20-22 °C) observing yellowing, chlorophyll degradation, and production of off-flavor. The broccolis stored in the temperature ranges of 0-2 and 5-7 °C maintained good quality for up to 12 days. The application of 1-MCP did not contribute to elongate the shelf life of Legacy broccoli at 20-22 °C, neither did it influence the preservation of the green color nor the avoidance of chlorophyll degradation. Keywords: color; chlorophyll; yellowing; chlorophyllases; ethylene. ResumoO etileno acelera o metabolismo pós-colheita de brócolis, e sua síntese é induzida por danos mecânicos e pelo aumento da temperatura. Para testar esta hipótese, foram realizados 03 experimentos. No primeiro, avaliou-se o efeito do dano mecânico na produção do etileno; no segundo, estudou-se o efeito do armazena...