scholarly journals Contrasting avoidance - tolerance in heat stress response from thermally contrasting climates in Arabidopsis thaliana

2016 ◽  
Author(s):  
Nana Zhang ◽  
Philip Carlucci ◽  
Joshua Nguyen ◽  
Jai-W Hayes-Jackson ◽  
Stephen Tonsor
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
High Temperature ◽  
Elevation Gradient ◽  
Branch Length ◽  
High Elevation ◽  
Tissue Temperature ◽  
Adaptive Divergence ◽  
Leaf Angle ◽  
Heat Stress Response

Plants ameliorate heat stress by avoiding heat loading, reducing tissue temperature through evaporative cooling, and/or through tolerance, i.e. maintaining function at high temperature. Here Arabidopsis thaliana natural populations from two ends of an elevation gradient in NE Spain were used to ask: do plants from contrasting climates 1) show genetically based differences in heat stress damage and 2) adopt different avoidance-tolerance patterns? Four low- and four high-elevation populations were repeatedly exposed to high temperature (45oC) in a growth chamber at bolting stage. High temperature induced 23% more inflorescence branches, 25% longer total reproductive branch length, and 12% less root dry mass, compared with control. However summed fruit length, hence fitness, decreased by 15%, populations did not differ significantly in fitness reduction. High elevation populations showed more avoidance, i.e. lower rosette temperature at 45oC. Low elevation populations showed more tolerance, maintaining relatively higher photosynthetic rate at 45oC. Avoidance was associated with high transpiration rate and flat rosette leaf angle. Tolerance was negatively associated with heat shock protein 101 (Hsp101) and salicylic acid (SA) accumulation. The divergent avoidance tolerance patterns for populations from thermally contrasting climates may indicate both constraints on the evolution and contrasting adaptive divergence regulated by local climates.

scholarly journals Adaptive divergence in transcriptome response to heat and acclimation in Arabidopsis thaliana plants from contrasting climates.

2016 ◽  
Author(s):  
Nana Zhang ◽  
Elizabeth Vierling ◽  
Stephen Tonsor
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
High Temperature ◽  
Expression Patterns ◽  
High Elevation ◽  
Adaptive Divergence ◽  
Gene Expression Patterns ◽  
Direct Exposure ◽  
Small Hsps

Phenotypic variation in stress response has been widely observed within species. This variation is an adaptive response to local climates and is controlled by gene sequence variation and especially by variation in expression at the transcriptome level. Plants from contrasting climates are thus expected to have different patterns in gene expression. Acclimation, a pre-exposure to sub-lethal temperature before exposing to extreme high temperature, is an important adaptive mechanism of plant survival. We are interested to evaluate the gene expression difference to heat stress for plants from contrasting climates and the role of acclimation in altering their gene expression pattern. Natural Arabidopsis thaliana plants from low elevation mediterranean and high elevation montane climates were exposed to two heat treatments at the bolting stage: a) 45 oC: a direct exposure to 45oC heat; b) 38/45 oC: an exposure to 45oC heat after a 38oC acclimation treatment. Variation in overall gene expression patterns was investigated. We also explored gene expression patterns for Hsp/Hsf pathway and reactive oxygen species (ROS) pathway. In both heat treatments, high elevation plants had more differentially expressed (DE) genes than low elevation plants. In 45 oC, only Hsp/Hsf pathway was activated in low elevation plants; both Hsp/Hsf and ROS pathways were activated in high elevation plants. Small Hsps had the highest magnitude of change in low elevation plants while Hsp70 and Hsp90 showed the largest magnitude of fold in high elevation plants. In 38/45 oC, Hsp/Hsf and ROS pathways were activated in both low and high elevation plants. Low elevation plants showed up-regulation in all Hsps, especially small Hsps; high elevation plants showed down-regulation in all Hsps. Low elevation and high elevation also adopted different genes in the ROS pathway. We also observed genes that shifted expression in both low and high elevation plants but with opposite directions of change. This study indicates that low and high elevation plants have evolved adaptive divergence in heat stress response. The contrasting patterns of temperature variation in low and high elevation sites appears to have played a strong role in the evolution of divergent patterns to high temperature stress, both pre-acclimation and direct exposure gene expression responses.

scholarly journals Transcriptome and translatome changes in germinated pollen under heat stress uncover roles of transporter genes involved in pollen tube growth

2020 ◽  
Author(s):  
Laetitia Poidevin ◽  
Javier Forment ◽  
Dilek Unal ◽  
Alejandro Ferrando
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
High Temperature ◽  
Heat Shock ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Tube Growth ◽  
Heat Shock Genes ◽  
Germinated Pollen

ABSTRACTPlant reproduction is one key biological process very sensitive to heat stress and, as a consequence, enhanced global warming poses serious threats to food security worldwide. In this work we have used a high-resolution ribosome profiling technology to study how heat affects both the transcriptome and the translatome of Arabidopsis thaliana pollen germinated in vitro. Overall, a high correlation between transcriptional and translational responses to high temperature was found, but specific regulations at the translational level were also present. We show that bona fide heat shock genes are induced by high temperature indicating that in vitro germinated pollen is a suitable system to understand the molecular basis of heat responses. Concurrently heat induced significant down-regulation of key membrane transporters required for pollen tube growth, thus uncovering heat-sensitive targets. We also found that a large subset of the heat-repressed transporters is specifically up-regulated, in a coordinated manner, with canonical heat-shock genes in pollen tubes grown in vitro and semi in vivo, based on published transcriptomes from Arabidopsis thaliana. Ribosome footprints were also detected in gene sequences annotated as non-coding, highlighting the potential for novel translatable genes and translational dynamics.

scholarly journals Characterization of novel pollen-expressed transcripts reveals their potential roles in pollen heat stress response in Arabidopsis thaliana

2020 ◽  
Author(s):  
Nicholas Rutley ◽  
Laetitia Poidevin ◽  
Tirza Doniger ◽  
Richard Tillet ◽  
Abhishek Rath ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
Regulatory Networks ◽  
Male Gametophyte ◽  
Open Reading Frames ◽  
Heat Stress Response ◽  
Rna Fragments ◽  
Response To Stress ◽  
Small Open Reading Frames

ABSTRACTThe male gametophyte is the most heat-sensitive of all plant tissues. In recent years, long noncoding RNAs (lncRNAs) have emerged as important components of cellular regulatory networks involved in most biological processes, including response to stress. While examining RNAseq datasets of developing and germinating Arabidopsis thaliana pollen exposed to heat stress (HS), we identified 66 novel and 246 recently-annotated intergenic expressed loci (XLOCs) of unknown function, with the majority encoding lncRNAs. Comparison to HS in cauline leaves and other RNAseq experiments, indicated 74% of the 312 XLOCs are pollen-specific, and at least 42% are HS-responsive. Phylogenetic analysis revealed 96% of the genes evolved recently in Brassicaceae. We found that 50 genes are putative targets of microRNAs, and that 30% of the XLOCs contain small open reading frames (ORFs) with homology to protein sequences. Finally, RNAseq of ribosome-protected RNA fragments together with predictions of periodic footprint of the ribosome P-sites indicated that 23 of these ORFs are likely to be translated. Our findings indicate that many of the 312 unknown genes might be functional, and play significant role in pollen biology, including the HS response.

scholarly journals Identification of Quantitative Trait Loci Controlling High-Temperature Tolerance in Cucumber (Cucumis sativus L.) Seedlings

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1155
Author(s):  
Shaoyun Dong ◽  
Song Zhang ◽  
Shuang Wei ◽  
Yanyan Liu ◽  
Caixia Li ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Phenotypic Variability ◽  
Temperature Tolerance ◽  
Cucumis Sativus L ◽  
Heat Stress Response ◽  
Cucumber Seedlings ◽  
Trait Loci

High temperature is one of the major abiotic stresses that affect cucumber growth and development. Heat stress often leads to metabolic malfunction, dehydration, wilting and death, which has a great impact on the yield and fruit quality. In this study, genetic analysis and quantitative trait loci (QTL) mapping for thermotolerance in cucumber seedlings was investigated using a recombinant inbred line (RILs; HR) population and a doubled haploid (DH; HP) population derived from two parental lines ‘65G’ (heat-sensitive) and ‘02245′ (heat-tolerant). Inheritance analysis suggested that both short-term extreme and long-term mild thermotolerance in cucumber seedlings were determined by multiple genes. Six QTLs for heat tolerance including qHT3.1, qHT3.2, qHT3.3, qHT4.1, qHT4.2, and qHT6.1 were detected. Among them, the major QTL, qHT3.2, was repeatedly detected for three times in HR and HP at different environments, explained 28.3% of the phenotypic variability. The 481.2 kb region harbored 79 genes, nine of which might involve in heat stress response. This study provides a basis for further identifying thermotolerant genes and helps understanding the molecular mechanism underlying thermotolerance in cucumber seedlings.

scholarly journals Niche expansion leads to small-scale adaptive divergence along an elevation gradient in a medium-sized passerine bird

2008 ◽  
Vol 275 (1647) ◽  
pp. 2155-2164 ◽  
Author(s):  
John E McCormack ◽  
Thomas B Smith
Keyword(s):  
Gene Flow ◽  
Regional Scale ◽  
Elevation Gradient ◽  
Passerine Bird ◽  
High Elevation ◽  
Adaptive Divergence ◽  
Small Scale ◽  
Niche Expansion ◽  
Aphelocoma Ultramarina ◽  
Pine Cones

Niche expansion can lead to adaptive differentiation and speciation, but there are few examples from contemporary niche expansions about how this process is initiated. We assess the consequences of a niche expansion by Mexican jays ( Aphelocoma ultramarina ) along an elevation gradient. We predicted that jays at high elevation would have straighter bills adapted to feeding on pine cones, whereas jays at low elevation would have hooked bills adapted to feeding on acorns. We measured morphological and genetic variation of 95 adult jays and found significant differences in hook length between elevations in accordance with predictions, a pattern corroborated by analysis at the regional scale. Genetic results from microsatellite and mtDNA variation support phenotypic differentiation in the presence of gene flow coupled with weak, but detectable genetic differentiation between high- and low-elevation populations. These results demonstrate that niche expansion can lead to adaptive divergence despite gene flow between parapatric populations along an elevation gradient, providing information on a key precursor to ecological speciation.

scholarly journals Heat and cold stresses phenotypes of Arabidopsis thaliana calmodulin mutants: regulation of gamma-aminobutyric acid shunt pathway under temperature stress

2012 ◽  
Vol 3 (1) ◽  
pp. 2 ◽  
Author(s):  
Nisreen A. AL-Quraan ◽  
Robert D. Locy ◽  
Narendra K. Singh
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
High Temperature ◽  
Seed Germination ◽  
Oxidative Damage ◽  
Temperature Stress ◽  
Wild Type ◽  
Gaba Shunt ◽  
Heat And Cold Stress

Plants have evolved mechanisms to cope with changes in surrounding temperatures. T-DNA insertions in seven calmodulin genes of <em>Arabidopsis thaliana</em> were used to investigate the role of specific calmodulin isoforms in tolerance of plants to low and high temperature for seed germination, susceptibility to low and high temperature induced oxidative damage, and changes in the levels of gammaaminobutyric acid (GABA) shunt metabolites in response to temperature stress. Exposure of wild type (WT) and <em>cam</em> mutant seeds at 4°C showed reduction in germination of <em>cam5-4</em> and <em>cam6-1</em> seeds. Exposure of cam seedlings to 42°C for 2 hr showed reduction in seed germination and survival of seedlings in <em>cam5-4</em> and <em>cam6-1</em> mutants compared to WT and other <em>cam</em> mutants. Oxidative damage by heat and cold stress measured as the level of malonaldehyde (MDA) was detected increased in root and shoot tissues of cam5- 4 and cam6-1. Oxidative damage by heat measured as the level of MDA was detected in root and shoot of most cam mutants with highest levels in <em>cam5-4</em> and <em>cam6-1</em>. Level of GABA shunt metabolites in seedlings were gradually increased after 1 hr and 3 hr with maximum level after 6 hr and 12 hr treatments at 4ºC. GABA shunt metabolites in both root and shoot were generally elevated after 30 min and 1 hr treatment at 42°C, and increased substantially after 2 hr at 42°C comparing to the control (no treatment). GABA and glutamate levels were increased significantly more than alanine in root and shoot tissues of all cam mutants and wild type compared to the control. Alanine levels showed significant decreases in all cam mutants and in WT for 30 and 60 min of heat stress. Sensitivity of <em>cam5-4 </em>and <em>cam6-1</em> to low temperatures suggests a role of the <em>CAM5</em> and <em>CAM6</em> genes in seed germination and protection against cold induced oxidative damage. Increases in the level of GABA shunt metabolites in response to cold treatment after initial reduction in some cam mutants suggests a role for calmodulin protein (<em>cam</em>) in the activation of glutamate decarboxylase (GAD) after exposure to cold, while increased metabolite levels may indicate involvement of other factors like reduction in cytoplasmic pH in cold regulation. Initial general elevation in GABA shunt metabolites after 30 min heat treatment in cam mutants suggests regulation of GABA level by <em>cam</em>. These data suggest that regulation by factors other than cam is likely, and that this factor may relate to the regulation of GAD by intracellular pH and/or metabolite partitioning under heat stress.

scholarly journals Characterization of novel pollen-expressed transcripts reveals their potential roles in pollen heat stress response in Arabidopsis thaliana

2021 ◽  
Vol 34 (1) ◽  
pp. 61-78
Author(s):  
Nicholas Rutley ◽  
Laetitia Poidevin ◽  
Tirza Doniger ◽  
Richard L. Tillett ◽  
Abhishek Rath ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
Stress Response ◽  
Unknown Function ◽  
Regulatory Networks ◽  
Male Gametophyte ◽  
Open Reading Frames ◽  
Heat Stress Response ◽  
Rna Fragments ◽  
Response To Stress

Abstract Key message Arabidopsis pollen transcriptome analysis revealed new intergenic transcripts of unknown function, many of which are long non-coding RNAs, that may function in pollen-specific processes, including the heat stress response. Abstract The male gametophyte is the most heat sensitive of all plant tissues. In recent years, long noncoding RNAs (lncRNAs) have emerged as important components of cellular regulatory networks involved in most biological processes, including response to stress. While examining RNAseq datasets of developing and germinating Arabidopsis thaliana pollen exposed to heat stress (HS), we identified 66 novel and 246 recently annotated intergenic expressed loci (XLOCs) of unknown function, with the majority encoding lncRNAs. Comparison with HS in cauline leaves and other RNAseq experiments indicated that 74% of the 312 XLOCs are pollen-specific, and at least 42% are HS-responsive. Phylogenetic analysis revealed that 96% of the genes evolved recently in Brassicaceae. We found that 50 genes are putative targets of microRNAs and that 30% of the XLOCs contain small open reading frames (ORFs) with homology to protein sequences. Finally, RNAseq of ribosome-protected RNA fragments together with predictions of periodic footprint of the ribosome P-sites indicated that 23 of these ORFs are likely to be translated. Our findings indicate that many of the 312 unknown genes might be functional and play a significant role in pollen biology, including the HS response.

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