Characterisation of Goats’ Response to Heat Stress: Tools to Improve Heat Tolerance

Abstract Background The effect of heat stress on livestock production is a worldwide issue. Animal performance is influenced by exposure to harsh environmental conditions potentially causing genotype-by-environment interactions (G × E), especially in highproducing animals. In this context, the main objectives of this study were to (1) detect the time periods in which heifer fertility traits are more sensitive to the exposure to high environmental temperature and/or humidity, (2) investigate G × E due to heat stress in heifer fertility traits, and, (3) identify genomic regions associated with heifer fertility and heat tolerance in Holstein cattle. Results Phenotypic records for three heifer fertility traits (i.e., age at first calving, interval from first to last service, and conception rate at the first service) were collected, from 2005 to 2018, for 56,998 Holstein heifers raised in 15 herds in the Beijing area (China). By integrating environmental data, including hourly air temperature and relative humidity, the critical periods in which the heifers are more sensitive to heat stress were located in more than 30 days before the first service for age at first calving and interval from first to last service, or 10 days before and less than 60 days after the first service for conception rate. Using reaction norm models, significant G × E was detected for all three traits regarding both environmental gradients, proportion of days exceeding heat threshold, and minimum temperature-humidity index. Through single-step genome-wide association studies, PLAG1, AMHR2, SP1, KRT8, KRT18, MLH1, and EOMES were suggested as candidate genes for heifer fertility. The genes HCRTR1, AGRP, PC, and GUCY1B1 are strong candidates for association with heat tolerance. Conclusions The critical periods in which the reproductive performance of heifers is more sensitive to heat stress are trait-dependent. Thus, detailed analysis should be conducted to determine this particular period for other fertility traits. The considerable magnitude of G × E and sire re-ranking indicates the necessity to consider G × E in dairy cattle breeding schemes. This will enable selection of more heat-tolerant animals with high reproductive efficiency under harsh climatic conditions. Lastly, the candidate genes identified to be linked with response to heat stress provide a better understanding of the underlying biological mechanisms of heat tolerance in dairy cattle.

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An ER–Golgi Tethering Factor SLOH4/MIP3 Is Involved in Long-term Heat Tolerance of Arabidopsis

Plant and Cell Physiology ◽

10.1093/pcp/pcaa157 ◽

2020 ◽

Author(s):

Kazuho Isono ◽

Ryo Tsukimoto ◽

Satoshi Iuchi ◽

Akihisa Shinozawa ◽

Izumi Yotsui ◽

...

Keyword(s):

Heat Stress ◽

Heat Tolerance ◽

Secretory Proteins ◽

Wild Type ◽

Additional Function ◽

Transcript Levels ◽

Unfolded Protein ◽

In The Wild ◽

Protein Response

Abstract Plants are often exposed not only to short-term (S-) heat stress but also to diurnal long-term (L-) heat stress over several consecutive days. To reveal the mechanisms underlying L-heat stress tolerance, we here used a forward genetic screening for sensitive to long-term heat (sloh) mutants and isolated sloh4. The mutant was hypersensitive to L- but not S-heat stress. The causal gene of sloh4 was identical to MIP3 encoding a member of the MAIGO2 (MAG2) tethering complex, which is composed of the MAG2, MIP1, MIP2, and MIP3 subunits and is localized at the endoplasmic reticulum (ER) membrane. Although sloh4/mip3 was hypersensitive to L-heat stress, the sensitivity of the mag2-3 and mip1–1 mutants was similar to that of the wild type. Under L-heat stress, the ER stress and the following unfolded protein response (UPR) were more pronounced in sloh4 than in the wild type. Transcript levels of bZIP60-regulated UPR genes were strongly increased in sloh4 under L-heat stress. Two processes known to be mediated by INOSITOL REQUIRING ENZYME1 (IRE1)—accumulation of the spliced bZIP60 transcript and a decrease in the transcript levels of PR4 and PRX34, encoding secretory proteins—were observed in sloh4 in response to L-heat stress. These findings suggest that misfolded proteins generated in sloh4 under L-heat stress may be recognized by IRE1 but not bZIP28, resulting in initiation of the UPR via activated bZIP60. Therefore, it would be possible that only MIP3 in MAG2 complex has an additional function in L-heat tolerance, which is not related to the ER–Golgi vesicle tethering.

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Heat-tolerant hot pepper exhibits constant photosynthesis via increased transpiration rate, high proline content and fast recovery in heat stress condition

Scientific Reports ◽

10.1038/s41598-021-93697-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sherzod Nigmatullayevich Rajametov ◽

Eun Young Yang ◽

Myeong Cheoul Cho ◽

Soo Young Chae ◽

Hyo Bong Jeong ◽

...

Keyword(s):

Heat Treatment ◽

Heat Stress ◽

Heat Tolerance ◽

Transpiration Rate ◽

Stress Condition ◽

Proline Content ◽

Hot Pepper ◽

Fast Recovery ◽

Heat Stress Condition ◽

Heat Tolerant

AbstractUnderstanding the mechanism for heat tolerance is important for the hot pepper breeding program to develop heat-tolerant cultivars in changing climate. This study was conducted to investigate physiological and biochemical parameters related to heat tolerance and to determine leaf heat damage levels critical for selecting heat-tolerant genotypes. Seedlings of two commercial cultivars, heat-tolerant ‘NW Bigarim’ (NB) and susceptible ‘Chyung Yang’ (CY), were grown in 42 °C for ten days. Photosynthesis, electrolyte conductivity, proline content were measured among seedlings during heat treatment. Photosynthetic rate was significantly reduced in ‘CY’ but not in ‘NB’ seedlings in 42 °C. Stomatal conductivity and transpiration rate was significantly higher in ‘NB’ than ‘CY’. Proline content was also significantly higher in ‘NB’. After heat treatment, leaf heat damages were determined as 0, 25, 50 and 75% and plants with different leaf heat damages were moved to a glasshouse (30–32/22–24 °C in day/night). The growth and developmental parameters were investigated until 70 days. ‘NB’ was significantly affected by leaf heat damages only in fruit yield while ‘CY’ was in fruit set, number and yield. ‘NB’ showed fast recovery after heat stress compared to ‘CY’. These results suggest that constant photosynthetic rate via increased transpiration rate as well as high proline content in heat stress condition confer faster recovery from heat damage of heat-tolerant cultivars in seedlings stages.

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Changes in genetic parameters for milk yield and heat tolerance in the Thai Holstein crossbred dairy population under different heat stress levels and over time

Journal of Dairy Science ◽

10.3168/jds.2021-20151 ◽

2021 ◽

Author(s):

P. Sungkhapreecha ◽

I. Misztal ◽

J. Hidalgo ◽

Y. Steyn ◽

S. Buaban ◽

...

Keyword(s):

Heat Stress ◽

Milk Yield ◽

Heat Tolerance ◽

Genetic Parameters ◽

Stress Levels ◽

Over Time

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Differential response to heat stress among evolutionary lineages of an aquatic invertebrate species complex

Biology Letters ◽

10.1098/rsbl.2018.0498 ◽

2018 ◽

Vol 14 (11) ◽

pp. 20180498 ◽

Cited By ~ 12

Author(s):

Sofia Paraskevopoulou ◽

Ralph Tiedemann ◽

Guntram Weithoff

Keyword(s):

Heat Stress ◽

Cryptic Species ◽

Heat Tolerance ◽

Species Complex ◽

Environmental Changes ◽

Integrative Taxonomy ◽

Sensu Stricto ◽

Apparent Temperature ◽

Phenotypic Trait ◽

Evolutionary Lineages

Under global warming scenarios, rising temperatures can constitute heat stress to which species may respond differentially. Within a described species, knowledge on cryptic diversity is of further relevance, as different lineages/cryptic species may respond differentially to environmental change. The Brachionus calyciflorus species complex (Rotifera), which was recently described using integrative taxonomy, is an essential component of aquatic ecosystems. Here, we tested the hypothesis that these (formerly cryptic) species differ in their heat tolerance. We assigned 47 clones with nuclear ITS1 (nuITS1) and mitochondrial COI (mtCOI) markers to evolutionary lineages, now named B. calyciflorus sensu stricto (s.s.) and B. fernandoi . We selected 15 representative clones and assessed their heat tolerance as a bi-dimensional phenotypic trait affected by both the intensity and duration of heat stress. We found two distinct groups, with B. calyciflorus s.s. clones having higher heat tolerance than the novel species B. fernandoi . This apparent temperature specialization among former cryptic species underscores the necessity of a sound species delimitation and assignment, when organismal responses to environmental changes are investigated.

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Effect of Timing of Heat Stress During Grain Filling on Two Wheat Varieties Differing in Heat Tolerance. II. Fractional Protein Accumulation

Functional Plant Biology ◽

10.1071/pp9960739 ◽

1996 ◽

Vol 23 (6) ◽

pp. 739 ◽

Cited By ~ 29

Author(s):

PJ Stone ◽

ME Nicolas

Keyword(s):

Heat Stress ◽

High Temperature ◽

Grain Growth ◽

Heat Tolerance ◽

Grain Filling ◽

Size Exclusion ◽

Protein Accumulation ◽

Wheat Varieties ◽

Grain Filling Period ◽

Very High

Short periods of very high temperature (> 35�C) are common during the grain filling period of wheat, and can significantly alter mature protein composition and consequently grain quality. This study was designed to determine the stage of grain growth at which fractional protein accumulation is most sensitive to a short heat stress, and to examine whether varietal differences in heat tolerance are expressed consistently throughout the grain filling period. Two varieties of wheat differing in heat tolerance (cvv. Egret and Oxley, tolerant and sensitive, respectively) were exposed to a short (5 day) period of very high temperature (40�C max, for 6 h each day) at 5-day intervals throughout grain filling, from 15 to 50 days after anthesis. Grain samples were taken throughout grain growth and analysed for protein content and composition (albumin/globulin, monomer, SDS-soluble polymer and SDS-insoluble polymer) using size-exclusion high-performance liquid chromatography. The timing of heat stress exerted a significant influence on the accumulation of total wheat protein and its fractions, and protein fractions differed in their responses to the timing of heat stress. Furthermore, wheat genotype influenced both the sensitivity of fractional protein accumulation to heat stress and the stage during grain filling at which maximum sensitivity to heat stress occurred.

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Cloning and function analysis of BAG family genes in wheat

Functional Plant Biology ◽

10.1071/fp15317 ◽

2016 ◽

Vol 43 (5) ◽

pp. 393

Author(s):

Shiming Ge ◽

Zhen Kang ◽

Ying Li ◽

Fuzhen Zhang ◽

Yinzhu Shen ◽

...

Keyword(s):

Heat Stress ◽

Salinity Stress ◽

Heat Tolerance ◽

Expressed Sequence Tag ◽

Function Analysis ◽

Pcr Analysis ◽

Subcellular Localisation ◽

Hybrid Technique ◽

Rt Pcr ◽

Conserved Domain

By analysing the cDNA microarray of the salt tolerant mutant of wheat RH8706–49 under salinity stress, our results showed an expressed sequence tag fragment and acquired an unknown gene (designated as TaBAG) with a BAG conserved domain through electronic cloning and RT–PCR technology. The gene was registered into GenBank (No. FJ599765). After homologous alignment analysis, electronic cloning, and amplifying with RT–PCR, the other gene with a BAG conserved domain, TaBAG2, was obtained and registered into GenBank (No. GU471210). Quantitative PCR analysis demonstrated that TaBAG2 expression was induced by saline and heat stress. TaBAG gene expression under salinity stress increased remarkably but showed an insignificant response to heat stress. The adversity stress detection results showed that Arabidopsis overexpressing TaBAG and TaBAG2 exhibited an obvious salt tolerance increase. Under heat stress, Arabidopsis overexpressing TaBAG2 showed increased heat tolerance; however, the heat tolerance of Arabidopsis overexpressing TaBAG did not vary significantly under heat stress. Subcellular localisation results demonstrated that TaBAGs were mainly located in the cytoplasm and the cell nucleus. We applied fluorescence complementation and yeast two-hybrid technique to prove that TaBAG2 can obviously bond with TaHsp70 and TaCaMs. After the respective mutation of aspartic acid (D) and arginine (R) at high conservation in BAG domain of TaBAG2, the bonding interaction between TaBAG2 and TaHsp70 disappeared, indicating that the two amino acids were the key loci for the interaction between TaBAG2 and TaHsp70. Heat tolerance detection results demonstrated that the heat tolerance of Arabidopsis overexpressing and cotransfected with TaBAG2 and TaHsp70 was much higher than that of Arabidopsis overexpressing TaBAG2 and Arabidopsis overexpressing TaHSP70. This finding implies that the synergistic use of TaBAG2 and TaHSP70 can improve heat tolerance of plants.

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Heat-tolerant Hot Pepper Exhibits Constant Photosynthesis Via Increased 4 Transpiration Rate, High Proline Content and Fast Recovery in Heat Stress 5 Condition

10.20944/preprints202107.0348.v1 ◽

2021 ◽

Author(s):

Sherzod Rajametov ◽

Eun Young Yang ◽

Myeong Cheoul Cho ◽

Soo Young Chae ◽

Hyo Bong Jeong ◽

...

Keyword(s):

Heat Treatment ◽

Heat Stress ◽

Photosynthetic Rate ◽

Heat Tolerance ◽

Transpiration Rate ◽

Proline Content ◽

Hot Pepper ◽

Fast Recovery ◽

Heat Damage ◽

Heat Tolerant

Understanding the mechanism for heat tolerance is important for the hot pepper breeding program to develop heat-tolerant cultivars in changing climate. This study was conducted to investigate physiological and biochemical parameters related to heat tolerance and to determine leaf heat damage levels critical for selecting heat-tolerant genotypes. Seedlings of two commercial cultivars, heat-tolerant ‘NW Bigarim’ (NB) and susceptible ‘Chyung Yang’ (CY), were grown in 42 °C for ten days. Photosynthesis, electrolyte conductivity, proline content were measured among seedlings during heat treatment. Photosynthetic rate was significantly reduced in ‘CY’ but not in ‘NB’ seedlings in 42 °C. Stomatal conductivity and transpiration rate was significantly higher in ‘NB’ than ‘CY’. Proline content was also significantly higher in ‘NB’. After heat treatment, leaf heat damages were determined as 0, 25, 50 and 75% and plants with different leaf heat damages were moved to a glasshouse (30–32/22–24 °C in day/night). The growth and developmental parameters were investigated until 70 days. ‘NB’ was significantly affected by leaf heat damages only in fruit yield while ‘CY’ was in fruit set, number and yield. ‘NB’ showed fast recovery after heat stress compared to ‘CY’. These results suggest that constant photosynthetic rate via increased transpiration rate as well as high proline content in heat stress condition confer faster recovery from heat damage of heat-tolerant cultivars in seedlings stages.

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Effect of Heat Treatment on Physiological and Recovery Growth Status of Two Tomato Cultivars With Different Heat Susceptibility

10.20944/preprints202102.0122.v1 ◽

2021 ◽

Author(s):

Sherzod Nigmatullayevich Rajametov ◽

Eun Young Yang ◽

Hyo Bong Jeong ◽

Myeong Cheoul Cho ◽

Soo-Young Chae ◽

...

Keyword(s):

Heat Stress ◽

High Temperature ◽

Stress Tolerance ◽

Heat Tolerance ◽

Fruit Set ◽

Fruit Size ◽

Seedling Stage ◽

Screening Methods ◽

Tomato Cultivars ◽

Heat Tolerant

High temperature seriously effects on plant vegetative and reproductive development and reduces productivity of plants, while to increase crop yield is the main target in most crop heat stress tolerance improvement breeding programs, not just survival, under high temperature. Our aim was to compare temperature stress tolerance in two commercial tomato cultivars “Dafnis” (big fruit size) and “Minichal” (cherry fruit size) to develop early screening methods and find out survival rate and physiological responses of tomato cultivars on high temperature (40°C and within 70% RH, day/night) in 4-5 true leaf seedling stage- (4LS) and identifies the linkage of heat tolerance with fruit set and leaf heat damage rates (LHD) in seedling stage with subsequent vegetative traits at recovery. Results showed that heat stress significantly affected on physiological-chemical and vegetative parameters of seedlings regardless of tomato cultivars. Survival and the threshold level of high temperature tolerance in the seedlings of cv. “Dafnis” and “Minichal” were identified on days 7 and 9, respectively. Our findings revealed that photosynthesis (PN, Gs, Ci, Tr) parameters were increased and CHL content persisted steady value in cv. “Minichal” during heat stress period, however EC and RPL rates were lower than cv. “Dafnis”. Heat stress reduced the SFW in both cultivars in seedling stage, but PH and RFW were significantly decreased in the heat tolerant cv. “Minichal”, whereas this parameters were not significantly ranged in the heat susceptible cv. “Dafnis”. Additionally, there no found linkage between vegetative parameters with decreasing of PN and CHL rates during HT of seedlings. In plants of cv. “Minichal” with LHD-25, 50 and 75% were no found significant differences in PH, whereas in cv. “Dafnis” significant differences were determined in plants with LHD-75%, and the significant differences in rates of SFW and RFW were observed in plants of cv. “Dafnis” having LHD-75% for 28 days of recovery at NT condition. Taken together, we concluded that heat stress affected on physiological parameters regardless of tolerance level, and to identify heat tolerant genotype in tomato breeding program, screening and selection genotypes have to be evaluated at the vegetative and reproductive stages with consideration fruit size types. Since we could not find linkage between heat tolerances in seedling stage with fruit set at the reproductive stage and fruit set cannot be used as a general predictor of heat tolerance.

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Chitosan (CTS) Alleviates Heat-Induced Leaf Senescence in Creeping Bentgrass by Regulating Chlorophyll Metabolism, Antioxidant Defense, and the Heat Shock Pathway

Molecules ◽

10.3390/molecules26175337 ◽

2021 ◽

Vol 26 (17) ◽

pp. 5337

Author(s):

Cheng Huang ◽

Yulong Tian ◽

Bingbing Zhang ◽

Muhammad Jawad Hassan ◽

Zhou Li ◽

...

Keyword(s):

Heat Stress ◽

Heat Shock ◽

Leaf Senescence ◽

Heat Tolerance ◽

Antioxidant Defense ◽

Creeping Bentgrass ◽

Grass Species ◽

Antioxidant Enzyme Activities ◽

Ros Scavenging ◽

Chlorophyll Metabolism

Chitosan (CTS) is a deacetylated derivative of chitin that is involved in adaptive response to abiotic stresses. However, the regulatory role of CTS in heat tolerance is still not fully understood in plants, especially in grass species. The aim of this study was to investigate whether the CTS could reduce heat-induced senescence and damage to creeping bentgrass associated with alterations in antioxidant defense, chlorophyll (Chl) metabolism, and the heat shock pathway. Plants were pretreated exogenously with or without CTS (0.1 g L−1) before being exposed to normal (23/18 °C) or high-temperature (38/33 °C) conditions for 15 days. Heat stress induced detrimental effects, including declines in leaf relative water content and photochemical efficiency, but significantly increased reactive oxygen species (ROS) accumulation, membrane lipid peroxidation, and Chl loss in leaves. The exogenous application of CTS significantly alleviated heat-induced damage in creeping bentgrass leaves by ameliorating water balance, ROS scavenging, the maintenance of Chl metabolism, and photosynthesis. Compared to untreated plants under heat stress, CTS-treated creeping bentgrass exhibited a significantly higher transcription level of genes involved in Chl biosynthesis (AsPBGD and AsCHLH), as well as a lower expression level of Chl degradation-related gene (AsPPH) and senescence-associated genes (AsSAG12, AsSAG39, Asl20, and Ash36), thus reducing leaf senescence and enhancing photosynthetic performance under heat stress. In addition, the foliar application of CTS significantly improved antioxidant enzyme activities (SOD, CAT, POD, and APX), thereby effectively reducing heat-induced oxidative damage. Furthermore, heat tolerance regulated by the CTS in creeping bentgrass was also associated with the heat shock pathway, since AsHSFA-6a and AsHSP82 were significantly up-regulated by the CTS during heat stress. The potential mechanisms of CTS-regulated thermotolerance associated with other metabolic pathways still need to be further studied in grass species.

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