ABSTRACT Blackberries have a short post-harvest conservation period, making it necessary to optimize harvest and storage conditions. The objective of this study was to evaluate the impact of refrigerated storage and maturation stage on the physicochemical quality of ‘BRS Cainguá’ blackberries, produced in an organic system. Blackberries from an experimental orchard, were harvested at three ripeness stages (RS), with RS1 being fruits with 100% red skin; RS2 skin 50% red and 50% black; and EM3 100% black skin. The samples were stored in a cold chamber at 4±0.5ºC and 90-95% RH for 12 days. The evaluations were carried out after 0, 3, 6, 9 and 12 days of storage, for: weight loss (WL), soluble solids (SS), pH, titratable acidity (TA), ratio (SS/TA) and color parameters. Blackberries harvested in RS3 had the highest SS content, lowest TA and the highest SS/TA ratio and pH. During storage, TA and WL showed decreasing and increasing linear responses, respectively, regardless of the RS of the fruits. Harvesting based on the skin color of ‘BRS Cainguá’ blackberries influences the physicochemical quality and postharvest conservation. Fruits harvested with 100% black skin, have the best quality and are the most suitable for subsequent refrigerated storage.

Abstract The aim of this study was: (i) understand how upstream signaling modulated TOR-SnRK1 nexus; and (ii) establish an interplay between SnRK1-TOR nexus, sugar availability, sucrolytic enzyme activities, expression level of key genes related to signalling and sugar metabolism, including trehalose, in in vitro-grown of ‘Myrobalan 29C’plum rootstock (Prunus cerasifera). Explants were cultivated in Murashigue and Skoog medium (MS) with trehalose (0; 1,0 and 10 mM). In 3 days, the antagonistic role of PcSnRK1 and PcTOR was confirmed in plants treated with 10mM trehalose, possibly indicating that ‘Myrobalan 29C’ was not in a stress condition. Furthermore, a PcTREA up-regulation was observed, which can lead to glucose accumulation, that in turn is precursor of sorbitol synthesis. Regarding the growth parameters evaluated after 21 days of in vitro culture, the uppermust number of shoots and explant length was observed at 10mM trehalose. Such positive response may be due to an increase in Glucose and UDP-Glc content, direct products of sucrose synthase (SuSy) enzyme. Consistent with these results, the highest availability of these molecules may be the upstream signal for TOR-activation. Interestingly, in this same condition, a sucrose accumulation was observed, which may also have contributed to PcTOR up-regulation and ameliorate in growth parameters.

Resumo O objetivo deste estudo foi: (i) compreender como a sinalização upstream modula o nexo TOR-SnRK1; e (ii) estabelecer uma interação entre o nexo SnRK1-TOR, disponibilidade de açúcar, atividades de enzimas sucrolíticas, nível de expressão de genes-chave relacionados à sinalização e metabolismo de açúcar, incluindo trealose, em porta-enxertos de ameixeira ‘Myrobalan 29C’ (Prunus cerasifera) cultivados in vitro. Explantes foram cultivados em meio Murashigue e Skoog (MS) com trealose (0; 1,0 e 10 mM). Aos 3 dias, o papel antagônico de PcSnRK1 e PcTOR foi confirmado em plantas tratadas com trealose 10mM, possivelmente indicando que ‘Myrobalan 29C’ não estava em uma condição de estresse. Além disso, foi observada uma regulação positiva do gene PcTREA, que pode levar ao acúmulo de glicose, que por sua vez é um precursor da síntese de sorbitol. Em relação aos parâmetros de crescimento avaliados após 21 dias de cultivo in vitro, o maior número de brotações e de comprimento do explante foi observado em resposta a trealose 10mM. Tais respostas positivas podem ser devido ao aumento do teor de glicose e UDPGlc, produtos diretos da enzima sacarose sintase (SuSy). Consistente com este resultado, a maior disponibilidade dessas moléculas pode ser o sinal upstream para ativação de TOR. Interessantemente, nesta mesma condição, foi observado um acúmulo de sacarose, o que também pode ter contribuído para o aumento da expressão do gene PcTOR e para a melhora nos parâmetros de crescimento.

ABSTRACT In the last decades, several biochemical and molecular studies in pear (Pyrus spp.) have revealed processes associated with dormancy establishment and release, leading to the identification of several MADS-box family genes related to bud dormancy regulation. Thus, the aim of this study was to evaluate a preliminary expression pattern of the PpDAM13-1 and PpDAM13-2 MADS-box genes in pear leaf buds (Pyrus pyrifolia Nakai, cultivars Hosui and Nijisseiki; and Pyrus communis L., cultivars Rocha and Santa Maria), grown in the subtropical climate of Southern Brazil. Lateral leaf buds were collected from June to September, and RNA was extracted for evaluation of gene expression by reverse transcription polymerase chain reaction (RT-qPCR). It was found that these two genes decreased the expression as leaf buds are release from dormancy. The Hosui cultivar for both genes and the Nijisseiki cultivar for PpDAM13-2 gene showed peaks of expression in early June, indicating that leaf buds are in a transition dormancy phase. The two European cultivars showed this transition dormancy phase between the end-July and the mid-August. It was concluded that the expression analysis of PpDAM13-1 and PpDAM13-2 genes can be used as a marker to evaluate changes of dormancy phase in pear trees in subtropical climate conditions, and it can be suitable to assist management strategies for overcoming pears’ bud dormancy.