Project description:The ability to rapidly respond to changes in temperature is critical for insects and other ectotherms living in variable environments. In a physiological process termed rapid cold-hardening (RCH), exposure to non-lethal low temperature allows many insects to significantly increase their cold tolerance in a matter of minutes to hours. Additionally, there are rapid changes in gene expression and cell physiology during recovery from cold injury, and we hypothesize that RCH may modulate some of these processes during recovery. In this study, we used a cDNA microarray to examine the molecular mechanisms of RCH and cold shock (CS) recovery in the flesh fly, Sarcophaga bullata. With our custom 2-color array, we measured expression of ~15,000 ESTs during RCH and during recovery from cold shock. Surprisingly, no transcripts were upregulated during RCH, and likewise, RCH had a minimal effect on the transcript signature during recovery from cold shock. However, during recovery from cold shock, we observed differential expression of ~1,400 ESTs, including a number of heat shock proteins, cytoskeletal components, and genes from several cell signaling pathways. Several gene pathways correlated well with metabolomics data, indicating that coordinated changes in gene expression and metabolism contribute to recovery from cold shock. Four treatment groups (C, RCH, CS+2R, RCH+CS+2R), four biological replicates of four pooled individuals for each treatment. Each phenotype was hybridized with the control, and the CS+2R and RCH+CS+2R groups were also hybridized together.
Project description:The ability to rapidly respond to changes in temperature is critical for insects and other ectotherms living in variable environments. In a physiological process termed rapid cold-hardening (RCH), exposure to non-lethal low temperature allows many insects to significantly increase their cold tolerance in a matter of minutes to hours. Additionally, there are rapid changes in gene expression and cell physiology during recovery from cold injury, and we hypothesize that RCH may modulate some of these processes during recovery. In this study, we used a cDNA microarray to examine the molecular mechanisms of RCH and cold shock (CS) recovery in the flesh fly, Sarcophaga bullata. With our custom 2-color array, we measured expression of ~15,000 ESTs during RCH and during recovery from cold shock. Surprisingly, no transcripts were upregulated during RCH, and likewise, RCH had a minimal effect on the transcript signature during recovery from cold shock. However, during recovery from cold shock, we observed differential expression of ~1,400 ESTs, including a number of heat shock proteins, cytoskeletal components, and genes from several cell signaling pathways. Several gene pathways correlated well with metabolomics data, indicating that coordinated changes in gene expression and metabolism contribute to recovery from cold shock.
Project description:Cold hardening treatment, a brief exposure to low temperatures (e.g. 0°C for 2 h), can protect certain insects against subsequent exposure to temperatures sufficiently low to cause damage or lethality. Microarray analysis to examine the changes in transcript abundance associated with cold hardening has been undertaken in Drosophila melanogaster in order to gain insight into this phenomenon. Transcripts associated with 36 genes were identified, a subset of which appeared to be also differentially expressed after heat shock treatment. Quantitative RT-PCR was used to independently determine transcript abundance of a subset of these sequences. Taken together, these assays suggest that stress proteins, including Hsp23, Hsp26, Hsp83 and Frost as well as membrane-associated proteins may contribute to the cold hardening response. Keywords: cold stress response
2005-12-01 | GSE2989 | GEO
Project description:RNA-seq unigene from Liriomyza sativae
Project description:Cold hardening treatment, a brief exposure to low temperatures (e.g. 0°C for 2 h), can protect certain insects against subsequent exposure to temperatures sufficiently low to cause damage or lethality. Microarray analysis to examine the changes in transcript abundance associated with cold hardening has been undertaken in Drosophila melanogaster in order to gain insight into this phenomenon. Transcripts associated with 36 genes were identified, a subset of which appeared to be also differentially expressed after heat shock treatment. Quantitative RT-PCR was used to independently determine transcript abundance of a subset of these sequences. Taken together, these assays suggest that stress proteins, including Hsp23, Hsp26, Hsp83 and Frost as well as membrane-associated proteins may contribute to the cold hardening response. Co-reared flies were separated into a control group and a treatment group at random. RNA was isolated from the cold-shocked flies and the respective controls and was used for direct comparisons on cDNA microarrays. Treatments were not varied as they had been optimized in previous studies. A pilot experiment was performed using the Drosophila 7k2 array (GPL311) and subsequently three pairs of independent biological samples were evaluated with the Drosophila 12k1 array (GPL1467).
Project description:Cold storage (CS) is widely used to extend fruit postharvest. In peach, chilling injuries may cause intense juice loss leading to a dry âwoollyâ texture of the fruit flesh. The disturbance, named woolliness, is associated to abnormal pectin metabolism and results in anatomical and physiological alterations. Application of gibberellic acid (GA) at the initial stages of pit hardening has been shown to impair woolliness incidence, however the mechanisms controlling the response remain unknown. We have employed genome wide transcription analyses to investigate the effects of GA application and CS of peaches. Approximately half (48.26%, 13846) of the investigated genes exhibited significant differential expression in response to the treatments. Gene ontology classes associated to cellular and developmental processes were overrepresented among the differentially regulated genes, whereas sequences classified in cell death and immune response categories were underrepresented. Gene set enrichment analyses demonstrated a predominant role of CS in repressing the transcription of genes associated to cell wall metabolism. In contrast, genes involved in hormone metabolism and signaling exhibited a more complex transcriptional response to the factors, indicating an extensive network of crosstalk between GA and low temperatures. Time course transcriptional profiling analyses also confirmed the involvement of cell wall metabolism genes in woolliness onset in peach. Overall, our results provide further insights on the mechanisms controlling the complex phenotypes associated to postharvest textural changes in peach. Four samples (CONT, CONTcs, GA3, GA3cs), each with three biological replicates (R1, R2 and R3), were analyzed. Control samples (CONT and CONTcs) consist of peach mesocarp not treated with GA3 at pit hardening, and either assayed at harvest (CONT) or after 15 days of cold storage (CONTcs). GA3 samples (GA3 and GA3cs) consist of peach mesocarp treated with GA3 at pit hardening, and either assayed at harvest (GA3) or after 15 days of cold storage (GA3cs).
Project description:Earlier findings indicated that light plays a critical role in the development of frost tolerance in winter cereals. However, the exact mechanism is still poorly understood. In the present work the effects of light during the cold acclimation period were studied in chilling-sensitive maize plants. The results show that although exposure to relatively high light intensities during cold acclimation at 15 °C causes various stress symptoms, it enhances the effectiveness of acclimation to chilling conditions (5 °C in the light). Interestingly, certain stress responses were light-dependent not only in the leaves, but also in the roots. A microarray study was also conducted to achieve a better understanding of the interaction of low temperature and light intensity during the cold hardening period. Numerous genes significantly differentially expressed were observed in almost all assimilation and metabolic pathways. Acclimation at moderately low temperature and low light intensity reduced the level of soluble sugars, while chilling increased it. Greater accumulation during hardening was detected at relatively high light intensity. It seems that the photoinhibition induced by low temperature is a necessary evil for cold acclimation processes in plants.