Uso de microarrays para a análise do perfil transcricional em polpa de maçã cv. Gala frente ao armazenamento refrigerado e ao uso do 1-metilciclopropeno.

O presente trabalho utilizou a técnica de microarrays para o estudo da influência do 1-metilciclopropeno (1-MCP) e do AR sobre o perfil transcricional de polpa de maçã 'Gala' armazenada por 60 dias

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

Effects of pre-harvest gibberellic acid spraying on gene transcript accumulation during peach fruit development.

In order to understand early molecular events associated with increase in fruit size and woolliness prevention induced by pre-harvest gibberellic acid (GA3) 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 ?Chiripa´? peach. Woolliness occurrence reached 100% in untreated peach, was reduced by 15% with GA3 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 GA3 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)

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. Keywords: Cold storage, gene expression, Malus x domestica, molecular analysi

Expression profile of rice Hsp genes under anoxic stress.

ABSTRACT: Although flooding is one of the most important environmental stresses worldwide, not all plant species are intolerant to its effects. Species from semi-aquatic environments, such as rice, have the capacity to cope with flooding stress. Heat-shock proteins (Hsps) are thought to contribute to cellular homeostasis under both optimal and adverse growth conditions. Studies of gene expression in plants exposed to low levels of oxygen revealed the up-regulation of Hsp genes. However, it is not clear whether Hsp genes are transcribed as a function of tolerance or whether they represent a response to anoxic stress. Therefore, the accumulation of Hsp gene transcripts was investigated in two different cultivars, 'Nipponbare' (flooding tolerant) and 'IPSL 2070' (flooding sensitive), subjected to anoxic stress. Fifteen-day-old rice root seedlings from both cultivars were used. Four different treatments were performed: no anoxia (control); 24-h anoxia; 48-h; and 72 anoxia; and 72-h anoxia. Anoxic stress was confirmed by the increased gene expression of alcohol dehydrogenase. The data obtained showed that both rice cultivars ('Nipponbare' and 'IPSL 2070') accumulated Hsp gene transcripts under anoxic stress; however, the majority of the Hsp genes evaluated were responsive to anoxic stress in 'IPSL 2070' (flooding sensitive), whereas in 'Nipponbare' (flooding tolerant), only six genes were highly up-regulated. This suggests that although Hsps have an important role in the response to anoxia, they are not the major cause of tolerance