High Temperature Stress Response Research Articles

Proteomic changes in rice leaves grown under open field high temperature stress conditions.

The interactive effect of temperature with other climatic and soil factors has profound influences on the growth and development of rice. The responses of rice to high temperatures under field conditions are more important than those under the controlled conditions. To understand the genes associated with high temperature stress response in general and tolerance in particular, the expression of all those genes associated with adaptation and tolerance in rice requires proteomic analysis. High temperature stress-tolerant cv. N22 was subjected to 28/18 °C (control) and 42/32 °C (high temperature stress) at flowering stage. The plants were grown in the field under the free air temperature increment condition. The proteomic changes in rice leaves due to high temperature stress were discussed. The proteomes of leaves had about 3000 protein spots, reproducibly detected on 2-dimensional electrophoretic gels with 573 proteins differentially expressed between the control and the high temperature treatments. Putative physiological functions suggested five categories such as growth (15.4%), heat shock proteins (7.7%), regulatory proteins (26.9%), redox homeostasis proteins (11.5%) and energy and metabolism (38.5%) related proteins. The results of the present study suggest that cv. N22, an agronomically recognized temperature tolerant rice cultivar copes with high temperature stress in a complex manner. Several functional proteins play important roles in its responses. The predicted climate change events necessitate more studies using this cultivar under different simulated ecological conditions to identify proteomic changes and the associated genes to be used as biomarkers and to gain a better understanding on the biochemical pathways involved in tolerance.

Identification of differentially expressed genes in Chrysanthemum nankingense (Asteraceae) under heat stress by RNA Seq

The RNA-Seq platform was used to characterize the high-temperature stress response of Chrysanthemum nankingense. A set of 54,668 differentially expressed unigenes was identified. After a threshold of ratio change ≥2 and a q-value of <0.05 were applied, the number of differentially transcribed genes was reduced to 3955, of which 765 were up-regulated and 3190 were down-regulated in response to heat stress. The differentially transcribed genes were predicted to participate in 26 biological processes, 4 cellular components, and 13 molecular functions. Among the most differentially expressed genes between the two libraries were well-recognized high-temperature responsive protein families, such as heat shock factors and heat shock proteins, various transcription factor families, and a number of RNA metabolism-related genes. Overall, the RNA-Seq analyses revealed a high degree of transcriptional complexity in early heat stress response. Some of these high-temperature responsive C. nankingense genes may prove useful in efforts to improve thermotolerance of commercial chrysanthemum.

Deep sequencing exposes small RNA transcriptome differences between low- and high-temperature stress responses in Arabidopsis

Plant small RNAs (sRNAs) include two major groups distinguished by their different modes of biogenesis - microRNAs (miRNAs) and small-interfering RNAs (siRNAs). Despite of numerous studies on the involvement of particular sRNA in plant stress response, there are only few reports on the genome-wide sRNA profiles generated under different stress treatments. To understand the involvement of the various sRNA groups in plant response to different stress factors, we characterized sRNA datasets produced by high-throughput sequencing (HTS) from Arabidopsis plants suffering from low-temperature (LT) and high-temperature (HT) stress for 24 hour. Our study for the first time presents the genome-wide sRNA profiles of LT and HT treated plants and reveals that they greatly differed in the first 24 hours of stress onset. Under the NT and LT conditions, the sRNA populations were dominated by 21-nt sRNAs. Another important finding is that there are many protein-coding genes that give rise to differentially expressed sRNAs following temperature shifts. The LT treatment caused increased production of sRNAs of sense polarity from numbers of cold-responsive genes such as COR15A, COR47, COR413, KIN2, KIN1. The HT treatment induced production of sRNAs of sense and antisense polarity from many genes encoding functionally diverse proteins. Amongst the temperature induced sRNA-producing loci, several can be selected whose sRNA profiles can be used to distinguish HTS libraries generated under low-temperature stress from those generated under high-temperature treatment.

Proteomics of rice grain under high temperature stress.

Recent proteomic analyses revealed dynamic changes of metabolisms during rice grain development. Interestingly, proteins involved in glycolysis, citric acid cycle, lipid metabolism, and proteolysis were accumulated at higher levels in mature grain than those of developing stages. High temperature (HT) stress in rice ripening period causes damaged (chalky) grains which have loosely packed round shape starch granules. The HT stress response on protein expression is complicated, and the molecular mechanism of the chalking of grain is obscure yet. Here, the current state on the proteomics research of rice grain grown under HT stress is briefly overviewed.

The C2 Domain Protein Cts1 Functions in the Calcineurin Signaling Circuit during High-Temperature Stress Responses in Cryptococcus neoformans

Calcineurin is a conserved calcium/calmodulin-dependent serine/threonine-specific protein phosphatase that acts in cell stress responses. Calcineurin is essential for growth at 37°C and for virulence of the human fungal pathogen Cryptococcus neoformans, but its substrates remain unknown. The C2 domain-containing, phospholipid-binding protein Cts1 was previously identified as a multicopy suppressor of a calcineurin mutation in C. neoformans. Here we further characterize the function of Cts1 and the links between Cts1 and calcineurin. GFP-Cts1 localizes to cytoplasmic puncta and colocalizes with the endosomal marker FM4-64. The cts1Δ mutant shows a distinct FM4-64 staining pattern, suggesting involvement of Cts1 in endocytic trafficking. In large budded cells, GFP-Cts1 localizes transiently at the mother bud neck, as a single ring that undergoes contraction. mCherry-Cts1 colocalizes with the GFP-tagged calcineurin catalytic subunit Cna1 at sites of mRNA processing at 37°C, suggesting that Cts1 and calcineurin function coordinately during thermal stress. GFP-Cts1 exhibits slower electrophoretic mobility for cells grown at 37°C than for cells grown at 24°C, and the shift to a higher molecular weight is more pronounced in the presence of the calcineurin inhibitor FK506. In vitro treatment with calf intestinal alkaline phosphatase (CIP) restores faster electrophoretic mobility to GFP-Cts1, suggesting that Cts1 is phosphorylated at 37°C and may be dephosphorylated in a calcineurin-dependent manner. mCherry-Cts1 also coimmunoprecipitates with GFP-Cna1, with greater complex formation at 37°C than at 24°C. Taken together, these findings support potential roles for Cts1 in endocytic trafficking, mRNA processing, and cytokinesis and suggest that Cts1 is a substrate of calcineurin during high-temperature stress responses.

Comparative analysis of the Spirulina platensis subcellular proteome in response to low- and high-temperature stresses: uncovering cross-talk of signaling components

The present study focused on comparative proteome analyses of low- and high-temperature stresses and potential protein-protein interaction networks, constructed by using a bioinformatics approach, in response to both stress conditions.The data revealed two important points: first, the results indicate that low-temperature stress is tightly linked with oxidative stress as well as photosynthesis; however, no specific mechanism is revealed in the case of the high-temperature stress response. Second, temperature stress was revealed to be linked with nitrogen and ammonia assimilation. Moreover, the data also highlighted the cross-talk of signaling pathways. Some of the detected signaling proteins, e.g., Hik14, Hik26 and Hik28, have potential interactions with differentially expressed proteins identified in both temperature stress conditions. Some differentially expressed proteins found in the Spirulina protein-protein interaction network were also examined for their physical interactions by a yeast two hybrid system (Y2H). The Y2H results obtained in this study suggests that the potential PPI network gives quite reliable potential interactions for Spirulina. Therefore, the bioinformatics approach employed in this study helps in the analysis of phenomena where proteome analyses of knockout mutants have not been carried out to directly examine for specificity or cross-talk of signaling components.

Proteomics를 이용한 고랭지 배추의 고온장해 해석

무더운 날씨가 지속됨으로서 고랭지배추의 생장 및 결구가 지연되고 있는 강원도 정선군 질운산(새빗재)의 600 m와 900 m의 배추를 사용하여 무기성분 및 단백질 발현패턴을 분석하였다. 식물체 무기성분에서는 생장에 관련된 질소 및 인산의 부족현상과 결구에 관련된 칼슘이 부족하였다. 단백체 분석은 2차원 전기영동에 의해 전체 126개의 단백질이 분리되었고 그중 48개의 단백질이 고도에 따라 변화하는 양상을 보여주었다. 이 중에서 30개의 단백질 서열이 결정되었는데, 해발 900 m에서 단백질 발현이 증가한 14개 중에서 oxygen- evolving proteins, rubisco activase and ATPase 등이, 해발 600 m에서는 glutathione S-transferase (1, 28 kD cold induced- and 24kD auxin-binding proteins) and salt-stress induced protein 등 16개의 단백질 발현이 증가하였다. 이러한 단백질은 식물체 손상에 대한 보호기작을 가진 스트레스관련 단백질로 가뭄, 온도상승, 밤낮의 온도차 등의 반복으로 복합적이며 동시 다발적으로 나타나는 고온장해 현상으로 사료된다. High temperature stresses have caused growth inhibition and delayed heading in highland cultivation Chinese cabbage during summer in Korea. We have studied high temperature stress responses in the terms of changes of inorganic components and proteins by proteomic analyses. Insufficiencies of nitrogen and phosphorus have affected growth rate and calcium deficiency has caused blunted heading. Proteins extracted from Brassica seedling grown at the altitude of 600m and 900m in the Mount Jilun were extracted and analysed by 2-dimentional polyacrylamide gel electrophoresis. Profiles of protein expression was then analyzed by 2-dimentional gel analyses. Protein spots showing different expression level were picked using the spot handling workstation and subjected to MALDI-TOF MS. Total 48 protein spots were analyzed by MALDI-TOF MS and 30 proteins spots out of 48 were identified by peptide mass fingerprinting analyses. Fourteen proteins were up-regulated in extracts from the altitude of 900m and they were identified as oxygen-evolving proteins, rubisco activase and ATPase etc. Sixteen proteins were up-regulated in extracts from the altitude of 600m and they were identified as glutathione S-transferase(1, 28kD cold induced- and 24 kD auxin-binding proteins) and salt-stress induced protein etc. These stress-induced proteins were related to the mediated protective mechanism against oxidative damage during various stresses. The results indicated that physiological phenomenon in response to high temperature stresses might be resulted by complex and multiple array of responses with drought, heat, oxidative, salt, and cold by high temperature.

Molecular characterization of a novel isoform of rice ( Oryza sativa L.) glycine rich-RNA binding protein and evidence for its involvement in high temperature stress response

A novel full-length cDNA encoding for glycine rich (GR)-RNA binding protein (RBP) ( Osgr-rbp4) is isolated from rice heat shock cDNA library. Amino acid sequence of the deduced protein reveals existence of RNA recognition motif (RRM) comprising of highly conserved RNA binding RNPI and RNPII domains at the N-terminus. C-terminus of this protein is rich in arginine and glycine residues. Blast search analysis on rice genome sequence database shows that GR-RBP protein family is constituted of multiple members with high level of amino acid conservation in RNA recognition motif and glycine domain regions. Similar analysis across wider biological systems from NCBI database indicated that rice GR-RBP4 has homologs in different living genera. Osgr-rbp4 transcript in rice seedlings is constitutively expressed as well as regulated by different abiotic stresses including high temperature stress. Ectopic over-expression of Osgr-rbp4 cDNA imparts high temperature stress tolerance to wild type yeast cells. It is shown that OsGR-RBP4 in rice leaf cells and its immunologically homologous protein in tobacco BY2 protoplasts are nuclear proteins. Upon heat shock, bulk of these proteins appears to be localized in the cytoplasm. We suggest that OsGR-RBP4 probably bind and stabilize the stress-inducible transcripts under HS conditions.

Metabolic Rate of Barley Root as a Continuous Function of Temperature

As part of an effort to define the nature of the physical changes in plant cells that trigger temperature stress responses, metabolic rates of root tissues of three barley ( Hordeum vulgare L.) cultivars were determined by differential temperature scanning calorimetry. Metabolic rate data were determined as a continuous function of temperature from near freezing to high temperatures that thermally inactivated metabolism. Two abrupt changes in metabolism were found, a largely reversible change resulting in a greatly increased temperature dependence at about 30 °C and an irreversible high temperature inactivation about four degrees higher. The temperatures at which these abrupt deviations from linear Arrhenius kinetics occurred were affected by degree of saturation of the lipids in root tissues, salt concentration in the medium, and the time-temperature program used in raising the samples to elevated temperatures. No physicochemical events were observed calorimetrically in temperature ranges where abrupt changes in metabolic rate were noted. Thus, if such a physicochemical change is the triggering event in high temperature stress responses in this species, it must involve less than about 5% of the total lipids or proteins in a first order event or be a thermodynamically higher order event.

EPR of a〈001〉Si interstitial complex in irradiated silicon

This paper deals with an electron-paramagnetic-resonance study of the $\mathrm{Si}\ensuremath{-}B3$ center, which was first reported by Daly. The $\mathrm{Si}\ensuremath{-}B3$ center is a secondary defect which forms upon annealing between 50 and 175\ifmmode^\circ\else\textdegree\fi{}C in irradiated boron-doped silicon and is stable up to $\ensuremath{\approx}500$\ifmmode^\circ\else\textdegree\fi{}C. Our studies indicate that the $\mathrm{Si}\ensuremath{-}B3$ center exhibits only a high-temperature stress response which is indicative of a thermally activated atomic reorientation at $T\ensuremath{\gtrsim}400$\ifmmode^\circ\else\textdegree\fi{}C. This defect does not exhibit a low-temperature stress response indicative of Jahn-Teller effects; consequently, the $\mathrm{Si}\ensuremath{-}B3$ center has inherent ${D}_{2d}$ symmetry by virtue of its molecular structure. The kinetics of this defect, the nature of the $^{29}\mathrm{Si}$ hyperfine interactions, and the symmetry of the defect suggest that the $\mathrm{Si}\ensuremath{-}B3$ corresponds to either a $〈001〉$ Si di-interstitial or a $〈001〉$ Si split interstitial. The $\mathrm{Si}\ensuremath{-}B3$ center appears to be similar but not identical to the $\mathrm{Si}P6$ center, which Lee and Corbett have recently suggested corresponds to a $〈001〉$ Si di-interstitial.