scholarly journals Characterization of Heat Responsive microRNAs and Phased Small Interfering RNAs in Reproductive Development of Flax

2021 ◽  
Author(s):  
Suresh Pokhrel ◽  
Blake C. Meyers

Plants will face increased heat stress due to rising global temperatures. Heat stress affects plant reproductive development and decreases productivity; however, the underlying molecular mechanisms of these processes are poorly characterized. Plant small RNAs (sRNAs) have important regulatory roles in plant reproductive development following abiotic stress responses. We generated sRNA transcriptomes of three reproductive bud stages at three different time points to identify sRNA-mediated pathways responsive to heat stress in flax. With added sRNA transcriptomes of vegetative tissues, we comprehensively annotated miRNA and phasiRNA-encoding genes (PHAS) in flax. We identified 173 miRNA genes, of which 42 are novel. Our analysis revealed that 141 miRNA genes were differentially expressed between tissue types while 18 miRNA genes were differentially expressed in reproductive tissues following heat stress, including members of miR2118/482 and miR2275 families, known triggers of reproductive phasiRNAs. Furthermore, we identified 68 21-PHAS flax loci from protein coding and non-coding regions, four 24-PHAS loci triggered by miR2275, and 658 24-PHAS-like loci with unknown triggers, derived mostly from non-coding regions. The reproductive phasiRNAs are mostly downregulated in response to heat stress. Overall, we found that several previously unreported miRNAs and phasiRNAs are responsive to heat stress in flax reproductive tissues.

Animals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 387 ◽  
Author(s):  
Zengkui Lu ◽  
Mingxing Chu ◽  
Qing Li ◽  
Meilin Jin ◽  
Xiaojuan Fei ◽  
...  

With the intensified and large-scale development of sheep husbandry and global warming, sheep heat stress has become an increasingly important issue. However, little is known about the molecular mechanisms related to sheep responses to heat stress. In this study, transcriptomic analysis of liver tissues of sheep in the presence and absence of heat stress was conducted, with the goal of identifying genes and pathways related to regulation when under such stress. After a comparison with the sheep reference genome, 440,226,436 clean reads were obtained from eight libraries. A p-value ≤ 0.05 and fold change ≥ 2 were taken as thresholds for categorizing differentially expressed genes, of which 1137 were identified. The accuracy and reliability of the RNA-Seq results were confirmed by qRT-PCR. The identified differentially expressed genes were significantly associated with 419 GO terms and 51 KEGG pathways, which suggested their participation in biological processes such as response to stress, immunoreaction, and fat metabolism. This study’s results provide a comprehensive overview of sheep heat stress-induced transcriptional expression patterns, laying a foundation for further analysis of the molecular mechanisms of sheep heat stress.


2021 ◽  
Vol 22 (5) ◽  
pp. 2481
Author(s):  
Jodi Callwood ◽  
Kalpalatha Melmaiee ◽  
Krishnanand P. Kulkarni ◽  
Amaranatha R. Vennapusa ◽  
Diarra Aicha ◽  
...  

Blueberries (Vaccinium spp.) are highly vulnerable to changing climatic conditions, especially increasing temperatures. To gain insight into mechanisms underpinning the response to heat stress, two blueberry species were subjected to heat stress for 6 and 9 h at 45 °C, and leaf samples were used to study the morpho-physiological and transcriptomic changes. As compared with Vaccinium corymbosum, Vaccinium darrowii exhibited thermal stress adaptation features such as small leaf size, parallel leaf orientation, waxy leaf coating, increased stomatal surface area, and stomatal closure. RNAseq analysis yielded ~135 million reads and identified 8305 differentially expressed genes (DEGs) during heat stress against the control samples. In V. corymbosum, 2861 and 4565 genes were differentially expressed at 6 and 9 h of heat stress, whereas in V. darrowii, 2516 and 3072 DEGs were differentially expressed at 6 and 9 h, respectively. Among the pathways, the protein processing in the endoplasmic reticulum (ER) was the highly enriched pathway in both the species: however, certain metabolic, fatty acid, photosynthesis-related, peroxisomal, and circadian rhythm pathways were enriched differently among the species. KEGG enrichment analysis of the DEGs revealed important biosynthesis and metabolic pathways crucial in response to heat stress. The GO terms enriched in both the species under heat stress were similar, but more DEGs were enriched for GO terms in V. darrowii than the V. corymbosum. Together, these results elucidate the differential response of morpho-physiological and molecular mechanisms used by both the blueberry species under heat stress, and help in understanding the complex mechanisms involved in heat stress tolerance.


2019 ◽  
Author(s):  
Zengkui Lu ◽  
Huihua Wang ◽  
Youji Ma ◽  
Mingxing Chu ◽  
Kai Quan ◽  
...  

Abstract Background: Intensive and large-scale development of the sheep industry and increases in global temperature are increasingly exposing sheep to heat stress. N6-methyladenosine (m6A) mRNA methylation varies in response to stress, and can link external stress with complex transcriptional and post-transcriptional processes. However, no m6A mRNA methylation map has been obtained for sheep, nor is it known what effect this has on regulating heat stress in sheep. Results: A total of 8,306 and 12,958 m6A peaks were detected in heat stress and control groups, respectively, with 2,697 and 5,494 genes associated with each. Peaks were mainly enriched in coding regions and near stop codons with classical RRACH motifs. Methylation levels of heat stress and control sheep were higher near stop codons, although methylation was significantly lower in heat stress sheep. GO revealed that differential m6A-containing genes were mainly enriched in the nucleus and were involved in several stress responses and substance metabolism processes. KEGG pathway analysis found that differential m6A-containing genes were significantly enriched in Rap1, FoxO, MAPK, and other signaling pathways of the stress response, and TGF-beta, AMPK, Wnt, and other signaling pathways involved in fat metabolism. These m6A-modified genes were moderately expressed in both heat stress and control sheep, and the enrichment of m6A modification was significantly negatively correlated with gene expression. Conclusions: Our results showed that m6A mRNA methylation modifications regulate heat stress in sheep, and it also provided a new way for the study of animal response to heat stress.


Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1015 ◽  
Author(s):  
Shuangming Yue ◽  
Zhisheng Wang ◽  
Lizhi Wang ◽  
Quanhui Peng ◽  
Bai Xue

Heat stress (HS) exerts significant effects on the production of dairy animals through impairing health and biological functions. However, the molecular mechanisms related to the effect of HS on dairy cow milk production are still largely unknown. The present study employed an RNA-sequencing approach to explore the molecular mechanisms associated with a decline in milk production by the functional analysis of differentially expressed genes (DEGs) in mammary glands of cows exposed to HS and non-heat-stressed cows. The results of the current study reveal that HS increases the rectal temperature and respiratory rate. Cows under HS result in decreased bodyweight, dry matter intake (DMI), and milk yield. In the current study, a total of 213 genes in experimental cow mammary glands was identified as being differentially expressed by DEGs analysis. Among identified genes, 89 were upregulated, and 124 were downregulated. Gene Ontology functional analysis found that biological processes, such as immune response, chaperone-dependent refolding of protein, and heat shock protein binding activity, were notably affected by HS. The Kyoto Encyclopedia of Genes and Genomes enrichment analysis found that almost all of the top-affected pathways were related to immune response. Under HS, the expression of heat shock protein 90 kDa beta I (HSP90B1) and heat shock 70 kDa protein 1A was upregulated, while the expression of bovine lymphocyte antigen (BoLA) and histocompatibility complex, class II, DRB3 (BoLA-DRB3) was downregulated. We further explored the effects of HS on lactation-related genes and pathways and found that HS significantly downregulated the casein genes. Furthermore, HS increased the expression of phosphorylation of mammalian target of rapamycin, cytosolic arginine sensor for mTORC1 subunit 2 (CASTOR2), and cytosolic arginine sensor for mTORC1 subunit 1 (CASTOR1), but decreased the phosphorylation of Janus kinase-2, a signal transducer and activator of transcription factor-5. Based on the findings of DMI, milk yield, casein gene expression, and the genes and pathways identified by functional annotation analysis, it is concluded that HS adversely affects the immune function of dairy cows. These results will be beneficial to understand the underlying mechanism of reduced milk yield in HS cows.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ying Liang ◽  
Kunhua Wei ◽  
Fan Wei ◽  
Shuangshuang Qin ◽  
Chuanhua Deng ◽  
...  

Abstract Background Sophora tonkinensis Gagnep is a traditional Chinese medical plant that is mainly cultivated in southern China. Drought stress is one of the major abiotic stresses that negatively impacts S. tonkinensis growth. However, the molecular mechanisms governing the responses to drought stress in S. tonkinensis at the transcriptional and posttranscriptional levels are not well understood. Results To identify genes and miRNAs involved in drought stress responses in S. tonkinensis, both mRNA and small RNA sequencing was performed in root samples under control, mild drought, and severe drought conditions. mRNA sequencing revealed 66,476 unigenes, and the differentially expressed unigenes (DEGs) were associated with several key pathways, including phenylpropanoid biosynthesis, sugar metabolism, and quinolizidine alkaloid biosynthesis pathways. A total of 10 and 30 transcription factors (TFs) were identified among the DEGs under mild and severe drought stress, respectively. Moreover, small RNA sequencing revealed a total of 368 miRNAs, including 255 known miRNAs and 113 novel miRNAs. The differentially expressed miRNAs and their target genes were involved in the regulation of plant hormone signal transduction, the spliceosome, and ribosomes. Analysis of the regulatory network involved in the response to drought stress revealed 37 differentially expressed miRNA-mRNA pairs. Conclusion This is the first study to simultaneously profile the expression patterns of mRNAs and miRNAs on a genome-wide scale to elucidate the molecular mechanisms of the drought stress responses of S. tonkinensis. Our results suggest that S. tonkinensis implements diverse mechanisms to modulate its responses to drought stress.


2019 ◽  
Vol 71 (2) ◽  
pp. 555-568 ◽  
Author(s):  
Neeta Lohani ◽  
Mohan B Singh ◽  
Prem L Bhalla

Abstract Climate change-induced increases in the frequency of extreme weather events, particularly heatwaves, are a serious threat to crop productivity. The productivity of grain crops is dependent on the success of sexual reproduction, which is very sensitive to heat stress. Male gametophyte development has been identified as the most heat-vulnerable stage. This review outlines the susceptibility of the various stages of sexual reproduction in flowering plants from the time of floral transition to double fertilization. We summarize current knowledge concerning the molecular mechanisms underpinning the heat stress-induced aberrations and abnormalities at flowering, male reproductive development, female reproductive development, and fertilization. We highlight the stage-specific bottlenecks in sexual reproduction, which regulate seed set and final yields under high-temperature conditions, together with the outstanding research questions concerning genotypic and species-specific differences in thermotolerance observed in crops. This knowledge is essential for trait selection and genetic modification strategies for the development of heat-tolerant genotypes and high-temperature-resilient crops.


Author(s):  
Kazuma Katano ◽  
Takao Oi ◽  
Nobuhiro Suzuki

ABSTRUCTHeat stress can seriously impact on yield production and quality of crops. Many studies uncovered the molecular mechanisms that regulate heat stress responses in plants. Nevertheless, effects of heat stress on the morphology of plants were still not extensively studied. In this study, we observed the detailed morphological changes of reproductive organs in Arabidopsis thaliana caused by heat stress. Larger area of stigma, and shorter length of anthers, filaments and petals were observed in plants subjected to heat stress compared to those under controlled conditions. Scanning electron microscopy (SEM) observation showed that length of stigmatic papillae without pollens seemed to be longer than that with pollens. In addition, classification of stigmas based on pollen attachment patterns together with artificial pollination assay revealed that pollen attachment onto stigma was clearly decreased by heat stress, and indicated that heat induced elongation of stigmatic papillae might be associated with disturbance of pollen attachment onto stigma. Furthermore, histochemical staining experiments revealed that crosstalk between Ca2+ and NO derived from pollens and O2− derived from stigma might be associated with morphological alteration of stigma.


Rice ◽  
2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Fan Zhang ◽  
Dan Zeng ◽  
Liyu Huang ◽  
Yingyao Shi ◽  
Tengjun Chen ◽  
...  

Abstract Background Salt stress and bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) are key limiting factors of rice (Oryza sativa L.) yields. Members of sucrose non-fermenting 1 (SNF1)-related protein kinase 2 (SnRK2), which is a family of plant-specific Ser/Thr kinases, are important components of signaling pathways involved in plant developmental processes and responses to stresses. There are 10 members of the SnRK2 family in rice; however, their functions are poorly understood, as are the underlying molecular mechanisms. Results In this study, we found that OsSAPK9, which belongs to the SnRK2 family, positively regulated salt-stress tolerance and strain-specific resistance to bacterial blight in rice. RNA sequencing revealed that there were 404 and 1324 genes differentially expressed in OsSAPK9-RNAi in comparison with wild-type plants under salt-stress conditions and after Xoo inoculation, respectively, which participate in basic metabolic processes. In total, 65 common differentially expressed genes involved mainly in defense responses were detected both under salt-stress conditions and after Xoo inoculation. Moreover, in vivo and in vitro experiments demonstrated that OsSAPK9 forms a protein complex with the molecular chaperones OsSGT1 and OsHsp90, and transgenic plants overexpressing OsSGT1 exhibited decreased tolerances to salt stress and significantly increased resistance levels to bacterial blight. Thus, OsSAPK9 may function as a center node regulator of salt-stress responses and disease-resistance pathways through its interaction with OsSGT1 in rice. Conclusion This study confirms that OsSAPK9 functions as a positive regulator of salt-stress responses and disease resistance through its interaction with OsSGT1 in rice.


2018 ◽  
Vol 70 (3) ◽  
pp. 551-557
Author(s):  
Marina Savicka ◽  
Aleksandrs Petjukevics ◽  
Anna Batjuka ◽  
Nataļja Skute

Global warming can negatively affect freshwater macrophytes. However, the degree to which freshwater plants can survive after long-term or short-term warming and the underlying molecular mechanisms are not fully understood. The aim of our study was to analyze the responses of an invasive plant to moderate heat stress (HS). Biochemical and physiological stress responses to experimental warming (30?}1.0?C/25?}1.0?C, day/night) were assessed in the invasive waterweed Elodea canadensis. The effect of the moderate HS on the macrophyte was evaluated through changes in the total protein content, catalase activity, lipid peroxidation, cellular membrane permeability by electrolyte leakage and the concentrations of carotenoids and photosynthetic pigments. Catalase activity and carotenoid concentrations increased significantly (p<0.01) in comparison to the control. A significant increase (p<0.05) in malondialdehyde concentration was observed. However, at the same time there was a persistent low level of electrolyte leakage in heat-treated plants as compared to the control. The results demonstrated that moderate HS improved membrane stability and increased the concentration of photosynthetic pigments and antioxidant activity in E. canadensis shoots. Moderate alterations in temperature may favorably affect the physiology and growth of the invasive macrophyte E. canadensis. It is reasonable to expect that warming could lead to a gradual change in E. canadensis distribution and to changes in composition of freshwater ecosystems.


2021 ◽  
Author(s):  
YaFan Chan ◽  
Chia-Yu Chen ◽  
Chih-Ying Lu ◽  
Yung-Chi Tu ◽  
Kshitij Tandon ◽  
...  

Endozoicomonas, a core bacterial group in corals, may also be a coral symbiont. Endozoicomonas communities often decrease rapidly in corals under heat stress. However, how the bacteria respond to changes in temperature and coral host during heat stress is unknown. Here, we employed the cultivable, dominant species E. montiporae as a working organism to explore how Endozoicomonas responds to heat stress. We designed two experiments to clarify the extent to which E. montiporae is influenced by temperature and coral host. We detected differentially expressed protein (DEP) profiles in this bacterium at 31°C and 33°C compared to 25°C by tandem mass tags-based quantitative proteome analysis. Fifty DEPs, including many heat shock proteins, were detected when the temperature changed. The expression of antioxidant defense proteins and key pyruvate synthase proteins decreased, suggesting that E. montiporae were in a physiology of stress at 33°C. Furthermore, some proteins were differentially expressed because of the heat-stress-treated coral lysate specifically, suggesting that not only heat but also heat-induced host factors can affect the protein expression of the bacterium. This study provides an in-depth analysis of how the molecular mechanisms of Endozoicomonas are affected by heat stress and coral host.


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