scholarly journals Inter- and intraspecific differences in Drosophila cold tolerance are linked to hindgut reabsorption capacity

2019 ◽  
Author(s):  
Mads Kuhlmann Andersen ◽  
Johannes Overgaard

AbstractMaintaining extracellular osmotic and ionic homeostasis is crucial to maintain organismal function. In insects, hemolymph volume and ion content is regulated by the combined actions of the secretory Malpighian tubules and reabsorptive hindgut. When exposed to stressful cold, homeostasis is gradually disrupted, characterized by a debilitating increase in extracellular K+ concentration (hyperkalemia). In accordance with this paradigm, studies have found a strong link between the cold tolerance of insect species and their ability to maintain ion and water homeostasis at low temperature. This is also the case for drosophilids where studies have already established how inter- and intra-specific differences in cold tolerance are linked to the secretory capacity of Malpighian tubules. However, presently there is little information on the effects of temperature on the reabsorptive capacity of the hindgut in Drosophila. To address this question we developed a novel method that allows for continued measurements of hindgut ion and fluid reabsorption in Drosophila. Firstly we demonstrate that this assay is temporally stable (> 3 hours) and that the preparation is responsive to humoral stimulation and pharmacological intervention of active and passive transport in accordance with the current insect hindgut reabsorption model. Using this method at benign (24°C) and low temperature (3°C) we investigated how cold acclimation or cold adaptation affected the thermal sensitivity of osmoregulatory function. We found that cold tolerant Drosophila species and cold-acclimated D. melanogaster are innately better at maintaining rates of fluid and Na+ reabsorption at low temperature. Furthermore, cold adaptation and acclimation causes a relative reduction in K+ reabsorption at low temperature. These characteristic responses of cold adapted/acclimated Drosophila will act to promote maintenance of ion and water homeostasis at low temperature and therefore provide further links between adaptations in osmoregulatory capacity of insects and their ability to tolerate cold exposure.


2020 ◽  
Author(s):  
Changbing Huang ◽  
Chun Jiang ◽  
limin Jin ◽  
Huanchao Zhang

Abstract Background:Hemerocallis fulva is a perennial herb belonging to Hemerocallis of Hemerocallis. Because of the large and bright colors, it is often used as a garden ornamental plant. But most varieties of H. fulva on the market will wither in winter, which will affect their beauty. It is very important to study the effect of low temperature stress on the physiological indexes of H. fulva and understand the cold tolerance of different H. fulva. MiRNA is a kind of endogenous non coding small molecular RNA with length of 21-24nt. It mainly inhibits protein translation by cutting target genes, and plays an important role in the development of organisms, gene expression and biological stress. Low temperature is the main abiotic stress affecting the production of H. fulva in China, which hinders the growth and development of plants. A comprehensive understanding of the expression pattern of microRNA in H. fulva under low temperature stress can improve our understanding of microRNA mediated stress response. Although there are many studies on miRNAs of various plants under cold stress at home and abroad, there are few studies on miRNAs related to cold stress of H. fulva. It is of great significance to explore the cold stress resistant gene resources of H. fulva, especially the identification and functional research of miRNA closely related to cold stress, for the breeding of excellent H. fulva.Results A total of 5619 cold-responsive miRNAs, 315 putative novel and 5 304 conserved miRNAs, were identified from the leaves and roots of two different varieties ‘Jinyan’ (cold-tolerant) and ‘Lucretius ’ (cold-sensitive), which were stressed under -4 oC for 24 h. Twelve conserved and three novel miRNAs (novel-miR10, novel-miR19 and novel-miR48) were differentially expressed in leaves of ‘Jinyan’ under cold stress. Novel-miR19, novel-miR29 and novel-miR30 were up-regulated in roots of ‘Jinyan’ under cold stress. Thirteen and two conserved miRNAs were deferentially expressed in leaves and roots of ‘Lucretius’ after cold stress. The deferentially expressed miRNAs between two cultivars under cold stress include novel miRNAs and the members of the miR156, miR166 and miR319 families. A total of 6 598 target genes for 6 516 known miRNAs and 82 novel miRNAs were predicted by bioinformatic analysis, mainly involved in metabolic processes and stress responses. Ten differentially expressed miRNAs and predicted target genes were confirmed by quantitative reverse transcription PCR(q-PCR), and the expressional changes of target genes were negatively correlated to differentially expressed miRNAs. Our data indicated that some candidate miRNAs (e.g., miR156a-3-p, miR319a, and novel-miR19) may play important roles in plant response to cold stress.Conclusions Our study indicates that some putative target genes and miRNA mediated metabolic processes and stress responses are significant to cold tolerance in H. fulva.



2020 ◽  
Author(s):  
Yipei Li ◽  
Xiaozhen Liu ◽  
Zhou Wei ◽  
Zhimin Zhang ◽  
Wen Bian ◽  
...  

Abstract Yellow kiwifruit ( Actinidia chinensis ) is highly susceptible to severe weather, such as low temperature and frost, which may affect the production in the coming year. And the cold-resistant mechanism of kiwifruit associated with gene regulation is poorly investigated. To botain cold-resistant germplam, to provide insight into the causes of differences in low temperature tolerance due to ploidy and to better understand cold-adaptive mechanisms in tetraploid kiwifruit, the diploid yellow kiwifruit ‘SWFU03’ and its tetraploid plantlets were subjected to cold-tolerant screening with L-hydroxyproline (L-Hyp) and low temperature, the selected ones were then analyzed by transcriptome data and confirmed by RT-qPCR. The results showed that the survival rate of tetraploid plants was 62.22% when treated with 8 mmol/L L-Hyp for 30 days, while all the diploid ones died. After treated with 0°C for 12 h, then at room temperature for seven days, the survival rate of tetraploid plantlets was 42.22%, while all diploidy died. Hence, cold tolerance of the tetraploid plantlets was stronger than that of the diploid genotypes. Using these two screening systems, 126 cold-resistant tetraploid tissue culture plantlets were obtained. A total of 1630 differentially expressed genes (DEGs) were identified, of which 619 were up-regulated and 1011 were down-regulated in the low temperature treatment goup. The DEGs enriched in the cold-tolerance related pathways mainly included plant hormone signal transduction, and starch and sucrose metabolism pathway. RT-qPCR analysis confirmed the expression levels of eight up-regulated genes in these pathways in the cold-resistant mutants. In conclusion, this study has identified cold-resistant yellow kiwifruit plantlets and cold-tolerance related genes. Moreover, the dataset got in this study advances our knowledge of the cold-adaptive genes in the regulatory networks and leads to understand the cold tolerance mechanisms in the tetraploid yellow kiwifruit.



2019 ◽  
Vol 20 (20) ◽  
pp. 5089 ◽  
Author(s):  
Hui Guo ◽  
Tingkai Wu ◽  
Shuxing Li ◽  
Qiang He ◽  
Zhanlie Yang ◽  
...  

Chilling stress is considered the major abiotic stress affecting the growth, development, and yield of rice. To understand the transcriptomic responses and methylation regulation of rice in response to chilling stress, we analyzed a cold-tolerant variety of rice (Oryza sativa L. cv. P427). The physiological properties, transcriptome, and methylation of cold-tolerant P427 seedlings under low-temperature stress (2–3 °C) were investigated. We found that P427 exhibited enhanced tolerance to low temperature, likely via increasing antioxidant enzyme activity and promoting the accumulation of abscisic acid (ABA). The Methylated DNA Immunoprecipitation Sequencing (MeDIP-seq) data showed that the number of methylation-altered genes was highest in P427 (5496) and slightly lower in Nipponbare (Nip) and 9311 (4528 and 3341, respectively), and only 2.7% (292) of methylation genes were detected as common differentially methylated genes (DMGs) related to cold tolerance in the three varieties. Transcriptome analyses revealed that 1654 genes had specifically altered expression in P427 under cold stress. These genes mainly belonged to transcription factor families, such as Myeloblastosis (MYB), APETALA2/ethylene-responsive element binding proteins (AP2-EREBP), NAM-ATAF-CUC (NAC) and WRKY. Fifty-one genes showed simultaneous methylation and expression level changes. Quantitative RT-PCR (qRT-PCR) results showed that genes involved in the ICE (inducer of CBF expression)-CBF (C-repeat binding factor)—COR (cold-regulated) pathway were highly expressed under cold stress, including the WRKY genes. The homologous gene Os03g0610900 of the open stomatal 1 (OST1) in rice was obtained by evolutionary tree analysis. Methylation in Os03g0610900 gene promoter region decreased, and the expression level of Os03g0610900 increased, suggesting that cold stress may lead to demethylation and increased gene expression of Os03g0610900. The ICE-CBF-COR pathway plays a vital role in the cold tolerance of the rice cultivar P427. Overall, this study demonstrates the differences in methylation and gene expression levels of P427 in response to low-temperature stress, providing a foundation for further investigations of the relationship between environmental stress, DNA methylation, and gene expression in rice.



2020 ◽  
Author(s):  
Angie Geraldine Sierra Rativa ◽  
Artur Teixeira de Araújo Junior ◽  
Daniele da Silva Friedrich ◽  
Rodrigo Gastmann ◽  
Thainá Inês Lamb ◽  
...  

AbstractRice (Oryza sativa L.) ssp. indica is the most cultivated species in the South of Brazil. However, these plants face low temperature stress from September to November, which is the period of early sowing, affecting plant development during the initial stages of growth, and reducing rice productivity. This study aimed to characterize the root response to low temperature stress during the early vegetative stage of two rice genotypes contrasting in their cold tolerance (CT, cold-tolerant; and CS, cold-sensitive). Root dry weight and length, as well as number of root hairs, were higher in CT than CS when exposed to cold treatment. Histochemical analyses indicated that roots of CS genotype present higher levels of lipid peroxidation and H2O2 accumulation, along with lower levels of plasma membrane integrity than CT under low temperature stress. RNAseq analyses revealed that the contrasting genotypes present completely different molecular responses to cold stress. The number of over-represented functional categories was lower in CT than CS under cold condition, suggesting that CS genotype is more impacted by low temperature stress than CT. Several genes might contribute to rice cold tolerance, including the ones related with cell wall remodeling, cytoskeleton and growth, signaling, antioxidant system, lipid metabolism, and stress response. On the other hand, high expression of the genes SRC2 (defense), root architecture associated 1 (growth), ACC oxidase, ethylene-responsive transcription factor, and cytokinin-O-glucosyltransferase 2 (hormone-related) seems to be related with cold sensibility. Since these two genotypes have a similar genetic background (sister lines), the differentially expressed genes found here can be considered candidate genes for cold tolerance and could be used in future biotechnological approaches aiming to increase rice tolerance to low temperature.



Genome ◽  
1995 ◽  
Vol 38 (5) ◽  
pp. 1023-1031 ◽  
Author(s):  
A. E. Limin ◽  
D. B. Fowler ◽  
M. Houde ◽  
L. P. Chauvin ◽  
F. Sarhan

Low-temperature response was measured at the whole plant and at the molecular level in wheat–rye amphiploids and in other interspecific combinations. Cold tolerance of interspecifics whose parents diverged widely in hardiness levels resembled the less hardy higher ploidy level wheat parent. Expression of the low-temperature induced Wcs120 gene of wheat (Triticum aestivum L. em. Thell.) has been associated with freezing tolerance and was used here to study mRNA and protein accumulation in interspecific and parental lines during cold acclimation. Northern and Western analyses showed that homologous mRNAs and proteins were present in all the related species used in the experiments. Cold-tolerant rye (Secale cereale L.) produced a strong mRNA signal that was sustained throughout the entire 49-day cold-acclimation period. The wheats produced a mRNA signal that had diminished after 49 days of low-temperature exposure. The wheat–rye triticales did not exhibit the independent accumulation kinetics of the cold-tolerant rye parent but, rather, more closely resembled the wheat parent in that the mRNA signal was greatly diminished after 49 days of low-temperature exposure. The influence of the rye genome was manifest in slightly greater mRNA and protein accumulation in earlier stages of acclimation. Protein accumulations in the triticales were also maintained to a somewhat greater extent than found in the wheats at the end of the 49-day acclimation period. Protein accumulations in the wheat-crested wheatgrass (Agropyron cristatum L. Gaertner) interspecific resembled that of the wheat parent. The influence of the higher ploidy level wheats of the expression of homologous gene families from wheat-related hardy diploids in interspecific combinations may in part explain the poor cold tolerance observed.Key words: cold tolerance, transcription, protein accumulation, alien gene expression, Triticeae.



2020 ◽  
Author(s):  
yinghua Pan ◽  
Haifu Liang ◽  
Lijun Gao ◽  
Gaoxing Dai ◽  
Weiwei Chen ◽  
...  

Abstract Background: Wild rice ( Oryza rufipogon Griff.) is an important germplasm resource for rice improvement. It has superior tolerance for many abiotic stresses including cold stress, but little is known about the mechanism underlying its resistance to cold. Low temperature is one of the most prevalent factors that limit rice productivity and geographical distribution.Results: This study aimed to elucidate the molecular genetic mechanisms of wild rice in tolerating low temperature. Comprehensive transcriptome profiles of two rice genotypes (cold-sensitive ce 253 and cold-tolerant Y12-4) at the germinating stage under cold stress were comparatively analyzed. A total of 42.44–68.71 million readings were obtained, resulting in the alignment of 29128 and 30131 genes in genotypes 253 and Y12-4, respectively. Many common and differentially expressed genes (DEGs) were analyzed in cold-sensitive and cold-tolerant genotypes. Results showed more upregulated DEGs in cold-tolerant genotypes than in cold-sensitive genotypes at four stages under cold stress. Gene ontology enrichment analyses indicated more upregulated genes than downregulated ones in cold-tolerant genotypes based on cellular process, metabolic process, response stimulus, membrane part, and catalytic activity. To confirm the RNA Sequencing (RNA-seq) data, Quantitative real time polymerase chain reaction (qRT-PCR) was performed on seven randomly selected DEGs. These genes showed similar expression patterns corresponding with the RNA-Seq method. We also explored a gene for cold tolerance LTG5 , encoding a UDP-glucosyltransferase. The overexpression of LTG5 gene conferred cold tolerance to indica rice.Conclusion: Overall, our results suggested that gene resources related to cold stress from wild rice can be valuable for improving the cold tolerance of crop plants.



Agronomy ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 40 ◽  
Author(s):  
Zhenghai Sun ◽  
Juan Du ◽  
Xiaoying Pu ◽  
Muhammad Kazim Ali ◽  
Xiaomeng Yang ◽  
...  

Low temperature stress severely hampers rice productivity, and hence elaborating chilling-mediated physiochemical alterations and unravelling cold tolerance pathways will facilitate cold resilient rice breeding. Various cold tolerant Near-isogenic lines (NILs) selected at the booting stage through backcrossing of a japonica landrace Lijing2 (cold tolerant) with cold sensitive Towada (a japonica cultivar). The cold tolerance attributes of NILs was validated over two years by evaluating the spikelet fertility followed by correlation of nineteen morphological traits with the rate of seed setting (RSS). Results revealed BG, FG, 1-2IL, RSLL, and UIL were significantly correlated with RSS and had nearer marker interval distance with cold tolerance in QTL analysis. Two QTLs, qCTB-7-a and qCTB-7-b, were found for RSS based on a mixed linear model. Alleles of two QTLs were contributed by Lijing2 and genetic distances between the peaks were 0.00 and 0.06cM, which explained 5.70% and 8.36% variation, respectively, One QTL for 1-2IL, RSLL, and ILBS, while two QTLs for FG, BG, and UIL were also identified. These findings can be exploited to engineer low temperature stress tolerant rice in times of climate change.



2021 ◽  
Author(s):  
Peng Jiao ◽  
Shiyou Jin ◽  
Nannan Chen ◽  
Chunlai Wang ◽  
Siyan Liu ◽  
...  

Abstract Maize (Zea mays L.) is a food crop sensitive to low temperatures. Low temperature, as one of the abiotic stress hazards, seriously affects the yield of corn. However, the genetic basis of low-temperature adaptation in maize is still poorly understood. In this study, maize S-adenosylmethionine decarboxylase (SAMDC) was localized on the nucleus. We introduced the SAMDC gene into the excellent maize inbred line variety GSH9901 and used Agrobacterium-mediated transformation to produce cold-tolerant transgenic maize lines. After a 3-year single-location field trial, the contents of polyamine (PA), proline, malondialdehyde, an antioxidant enzyme, and APX in the leaves of transgenic maize plants overexpressing SAMDC were significantly increased, and the introduction of the SAMDC gene was significantly increased the expression of CBFs and cold-related genes.The agronomic traits of overexpression maize changed and the yield traits were significantly improved, but no significant changes were found in plant height, ear length, and shaft thickness.Thus, engineering the SAMDC enzyme is an effective strategy to improve the cold tolerance and value of maize.



2021 ◽  
Vol 12 ◽  
Author(s):  
Xin Wang ◽  
Yue Liu ◽  
Zhongkui Han ◽  
Yuning Chen ◽  
Dongxin Huai ◽  
...  

Low temperature (non-freezing) is one of the major limiting factors in peanut (Arachis hypogaea L.) growth, yield, and geographic distribution. Due to the complexity of cold-resistance trait in peanut, the molecular mechanism of cold tolerance and related gene networks were largely unknown. In this study, metabolomic analysis of two peanut cultivars subjected to chilling stress obtained a set of cold-responsive metabolites, including several carbohydrates and polyamines. These substances showed a higher accumulation pattern in cold-tolerant variety SLH than cold-susceptible variety ZH12 under cold stress, indicating their importance in protecting peanut from chilling injuries. In addition, 3,620 cold tolerance genes (CTGs) were identified by transcriptome sequencing, and the CTGs were most significantly enriched in the “phenylpropanoid biosynthesis” pathway. Two vital modules and several novel hub genes were obtained by weighted gene co-expression network analysis (WGCNA). Several key genes involved in soluble sugar, polyamine, and G-lignin biosynthetic pathways were substantially higher and/or responded more quickly in SLH (cold tolerant) than ZH12 (cold susceptible) under low temperature, suggesting they might be crucial contributors during the adaptation of peanut to low temperature. These findings will not only provide valuable resources for study of cold resistance in peanut but also lay a foundation for genetic modification of cold regulators to enhance stress tolerance in crops.



Agriculture ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 162 ◽  
Author(s):  
Doan Cong Dien ◽  
Takeo Yamakawa

Owing to its origin in tropical and subtropical areas, rice is susceptible to cold stress. Low temperatures at the germination and seedling stages can result in seed loss, a delayed transplanting period, and lower final yield. In this study, 181 rice varieties from around the world were investigated for cold tolerance at the germination and seedling stages. At the germination stage, the responses of different rice varieties were examined based on the germination index, coleoptile length, and radicle length at low (13 °C) and control temperatures (25 °C). Significant variations in the germination index, coleoptile length, and radicle length were observed among varieties. Low temperature significantly decreased germination ability, and coleoptile and radicle growth in the studied varieties. At the seedling stage, cold tolerance of the rice varieties was evaluated based on the leaf color score under natural low temperature. Similar to the germination stage, at the seedling stage, significant variation in root and shoot growth was observed in the response of rice varieties to low temperature conditions. Based on the results from both the germination and seedling stages, two varieties (Hei-Chiao-Chui-Li-Hsiang and Ta-Mao-Tao) were selected as the best cold-tolerant varieties. Our results also indicate the benefits of warming treatments to protect rice seedlings from low temperature conditions.



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