scholarly journals The Use of High-Throughput Phenotyping for Assessment of Heat Stress-Induced Changes in Arabidopsis

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Ge Gao ◽  
Mark A. Tester ◽  
Magdalena M. Julkowska

The worldwide rise in heatwave frequency poses a threat to plant survival and productivity. Determining the new marker phenotypes that show reproducible response to heat stress and contribute to heat stress tolerance is becoming a priority. In this study, we describe a protocol focusing on the daily changes in plant morphology and photosynthetic performance after exposure to heat stress using an automated noninvasive phenotyping system. Heat stress exposure resulted in an acute reduction of the quantum yield of photosystem II and increased leaf angle. In longer term, the exposure to heat also affected plant growth and morphology. By tracking the recovery period of the WT and mutants impaired in thermotolerance (hsp101), we observed that the difference in maximum quantum yield, quenching, rosette size, and morphology. By examining the correlation across the traits throughout time, we observed that early changes in photochemical quenching corresponded with the rosette size at later stages, which suggests the contribution of quenching to overall heat tolerance. We also determined that 6 h of heat stress provides the most informative insight in plant’s responses to heat, as it shows a clear separation between treated and nontreated plants as well as the WT and hsp101. Our work streamlines future discoveries by providing an experimental protocol, data analysis pipeline, and new phenotypes that could be used as targets in thermotolerance screenings.

2019 ◽  
Author(s):  
Ge Gao ◽  
Mark A. Tester ◽  
Magdalena M. Julkowska

AbstractThe worldwide rise in heatwave frequency poses a threat to plant survival and productivity. Determining the new marker phenotypes that show reproducible response to heat stress and contribute to heat stress tolerance is becoming a priority. In this study, we describe a protocol focusing on the daily changes in plant morphology and photosynthetic performance after exposure to heat stress using an automated non-invasive phenotyping system. Heat stress exposure resulted in an acute reduction of quantum yield of photosystem II and increased leaf angle. In the longer term, exposure to heat also affected plant growth and morphology. By tracking the recovery period of WT and mutants impaired in thermotolerance (hsp101), we observed that the difference in maximum quantum yield, quenching, rosette size, and morphology. By examining the correlation across the traits throughout time, we observed that early changes in photochemical quenching corresponded with the rosette size at later stages, which suggests the contribution of quenching to overall heat tolerance. We also determined that 6h of heat stress provides the most informative insight in plant responses to heat, as it shows a clear separation between treated and non-treated plants as well as WT and hsp101. Our work streamlines future discoveries by providing an experimental protocol, data analysis pipeline and new phenotypes that could be used as targets in thermotolerance screenings.


1996 ◽  
Vol 270 (6) ◽  
pp. F1057-F1065 ◽  
Author(s):  
Y. H. Wang ◽  
S. C. Borkan

The 72-kDa heat stress protein (HSP-72) is an inducible cytoprotectant protein. Although transient renal ischemia in vivo induces HSP-72, it is not known whether prior heat stress protects renal epithelial cells from injury mediated by ATP depletion. To evaluate this hypothesis, opossum kidney (OK) cells were exposed to sodium cyanide and 2-deoxy-D-glucose in the absence of medium glucose, a maneuver that reduced cell ATP content to < 10% of the control value within 10 min and decreased cell survival. One day after 2 h of ATP depletion, OK cells previously exposed to heat stress (to induce accumulation of HSP-72) exhibited marked improvement in survival (a > 4-fold increase in total DNA), less uptake of vital dye, and less release of lactate dehydrogenase (LDH) than cells subjected to ATP depletion alone (23.0 +/- 1.6 vs. 34.1 +/- 1.2% of total LDH, respectively). Enhanced clonogenicity post-heat stress was completely prevented by cycloheximide and positively correlated with the steady-state content of HSP-72. In the recovery period after ATP depletion, cell ATP content, maximum mitochondrial ATP production rate, and total LDH activity were all significantly higher in cells with abundant HSP-72. Although the protective effects associated with heat stress are likely to be multifactoral, preserved cell metabolism and higher ATP content could enhance cellular repair processes after ATP depletion.


2018 ◽  
Vol 56 ◽  
pp. 136-140
Author(s):  
G. S. Sharapa ◽  
O. V. Boyko

Scientific and production experiments were carried out on cows of Ukrainian Black-and-White diary breed (UBAWD) of SE "Seagull" (branch "Lisne") during 2016–2017. The anatomical and physiological state of genital organs of cows was determined by the method of clinical and gynecological research of animals before conducting experiments and during them every 40–50 days. In total 486 cows were kept under control, which were kept in typical rooms with running platforms, but the active motivation of animals was clearly insufficient. Feeding cows according to the recommended standards. The milk yield from the cow in 2017 was 7813 kg. The experiments studied the effect of feeding cows during the dry period, the conditions of retention and some other paratypic factors on the course of the genera and the postnatal period, the duration of the service period and the fertility of cows. In analyzing the research results, personal records and veterinary documentation were used. In conducting experiments, it was found that normal calving was in 89% of cows, and severe and pathological – in 11% of cases. The main diseases in the afterlife period were: detention of the litter – 9.5%, postpartum endometritis – 21.5%, hypofunction of the ovaries – 23.0%, persistent yellow ovarian bodies – 25.6% and others. Normal intervals between stages of excitation of the sexual cycle (18–22 days) were in 63% of cows, and violations of the rhythm of sexual cycle, associated with dysfunction of the ovaries and missed the hunt – 30% of animals. Subunvulation of the genital organs of the cows contributed to the diseases of the limbs, udder and digestive disorders. During 2016–2017, the effect of feeding cows (173 g.) in the dry period on the course of calving, post-autumn period and their fertility was studied. Under the same conditions, keeping cows in the maternity ward and feeding rough and succulent feeds concentrated feeds fed cows of the control group (98 heads) to 1–2 kg daily during the dry period, and experimental (75 heads) – for 18–20 days to calving 2–3 kg. A positive difference was found in favor of cows of the experimental group: there was a more active stage of expulsion of the fetus, less delay of the placenta (by 7%) and endometritis (by 12%), the duration of the postoperative regenerative period decreased by 8.6 days; service period – 19.0 days; fertility from two inseminans was higher by 5.7%. Study of the reproductive capacity of cows at the hotel in different seasons showed that the recovery period was shorter by 11 days in the presence of cows in 3–4 quarters, and the service period – by 23.2 days at hotel in I and IV sq. The average duration of the recovery period was 79.5 days, while the service period was 123.4 days. The longest duration of the joint ventricle was in cows at hotel during the hot summer days of the year. The average fertilization rate from the first insemination of 339 cows was 44.9% with fluctuations in individual groups of milkers from 26.8% to 55.0%. The following indicators were in the number 1 and number 3 (respectively 26.8% and 31.4%). The best fertility rates were in groups № 4, 6 and 7, where there were more cows of the second and third lactation, and the responsible attitude of the milkers to work in organizing cows walks and sexually explicit hunting. When comparing the assessment of the duration of the IP and SP in full-age cows and cows, the first-born, taking into account 225 goals. It was found that these indicators were longer in primitive cows – 20.7 days respectively and 21.9 days in relation to full-age cows. The obtained results are completely consistent with the results obtained by a number of both domestic and foreign researchers. More attention is needed to grow heifers and to prepare newborns for delivery. In 15–17% of cows at and after the hotel, gynecological diseases that occurred in the presence of gastrointestinal diseases, lameness, mastitis and others were diagnosed. This has negatively affected the overall performance of the herd. In studying the duration of HP and SP in healthy and sick cows after calving, it was found that if the SP in healthy cows lasts 73.4 days, then in patients – 116.3 days (the difference was 42.9 days), and the difference in the duration of the joint venture reached 98.7 days. On the basis of the results of the research, it can be concluded that the reproductive function of the cows is influenced by such paratypic factors as feeding animals in the dry period, the temperature factor (time of year), the human factor (the effect of milking on a group of cows), age and physiological state of cows in the hotel and in the afterlife period. When feeding 2–3 kg of bovine feed for cows, together with rough and juicy fodder for 18–20 days prior to calving, the recovery period decreased by 8.6 days and service period – by 19 days, and fertility from two inseminals increased by 5.7%, reaching 85.3%. The smallest duration of the service-period was in the presence of cows in the I and IV quarters year (107.7–117.1 days). In primary cows, the recovery period was longer than that of full-age cows by 20.7 days, and the service period was 21.9 days. In the physiologically healthy cows after calving, the recovery period lasted an average of 73.4 days and service period – 98.7 days, and in patients, after the prescribed treatment – respectively 116.3 days and 197.4 days.


2021 ◽  
Vol 12 ◽  
Author(s):  
Gábor Bernát ◽  
Tomáš Zavřel ◽  
Eva Kotabová ◽  
László Kovács ◽  
Gábor Steinbach ◽  
...  

Photomorphogenesis is a process by which photosynthetic organisms perceive external light parameters, including light quality (color), and adjust cellular metabolism, growth rates and other parameters, in order to survive in a changing light environment. In this study we comprehensively explored the light color acclimation of Cyanobium gracile, a common cyanobacterium in turbid freshwater shallow lakes, using nine different monochromatic growth lights covering the whole visible spectrum from 435 to 687 nm. According to incident light wavelength, C. gracile cells performed great plasticity in terms of pigment composition, antenna size, and photosystem stoichiometry, to optimize their photosynthetic performance and to redox poise their intersystem electron transport chain. In spite of such compensatory strategies, C. gracile, like other cyanobacteria, uses blue and near far-red light less efficiently than orange or red light, which involves moderate growth rates, reduced cell volumes and lower electron transport rates. Unfavorable light conditions, where neither chlorophyll nor phycobilisomes absorb light sufficiently, are compensated by an enhanced antenna size. Increasing the wavelength of the growth light is accompanied by increasing photosystem II to photosystem I ratios, which involve better light utilization in the red spectral region. This is surprisingly accompanied by a partial excitonic antenna decoupling, which was the highest in the cells grown under 687 nm light. So far, a similar phenomenon is known to be induced only by strong light; here we demonstrate that under certain physiological conditions such decoupling is also possible to be induced by weak light. This suggests that suboptimal photosynthetic performance of the near far-red light grown C. gracile cells is due to a solid redox- and/or signal-imbalance, which leads to the activation of this short-term light acclimation process. Using a variety of photo-biophysical methods, we also demonstrate that under blue wavelengths, excessive light is quenched through orange carotenoid protein mediated non-photochemical quenching, whereas under orange/red wavelengths state transitions are involved in photoprotection.


Author(s):  
V. Jaldhani ◽  
D. Sanjeeva Rao ◽  
P. Beulah ◽  
B. Srikanth ◽  
P. R. Rao ◽  
...  

Aims: To assess heat-induced PSII damage and efficiency in eight promising backcross introgression lines (BC2F6) of KMR-3R/N22 possessing qHTSF1.1 and qHTSF4.1. Study Design:  Randomized Complete Block Design (RCBD) with three replications. Place and Duration of Study: ICAR-Indian Institute of Rice Research, Hyderabad India during wet/rainy (Kharif) season 2018. Methodology: Eight ILs (BC2F6) and parents were evaluated for heat tolerance. The high- temperature stress was imposed by enclosing the crop with a poly cover tent (Polyhouse) just before the anthesis stage. The fluorescence parameters viz., maximum efficiency of PSII photochemistry (Fv/Fm), Electron transport rate (ETR), effective PSII quantum yield (ΦPSII), coefficient of photochemical quenching (qP) and coefficient of non-photochemical quenching (qN) were measured under ambient and high-temperature stress. Results: The heat-tolerance potential of ILs was assessed in terms of PSII activity. The results indicated that significant differences were observed between treatments (T), genotypes (G) and the interaction between T × G.  The physiological basis of introgressed QTLs controls the spikelet fertility by maintaining the productive and adaptive strategies in heat-tolerant QTL introgressed lines with stable photosynthetic apparatus (PSII) under high-temperature stress. Conclusion: The Fv/Fm ratio denotes the maximum quantum yield of PSII. The heat-tolerant QTL introgressed lines exhibited stable photosynthetic apparatus (PSII) and noted better performance under high-temperature stress. They may be used as donors for fluorescence traits in breeding rice for high-temperature tolerance.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 156-157
Author(s):  
Shelby M Ramirez ◽  
Janaka Wickramasinghe ◽  
Nadiia Stepanchenko ◽  
Maria Oconitrillo ◽  
Jayamuni Silva ◽  
...  

Abstract Phytogenic feed additives that contain anti-inflammatory and antioxidant properties may have potential to reduce inflammation and oxidation observed during bouts of heat stress. The trial objective was to determine the effects of a phytogenic feed additive on markers of stress in heifers subjected to diurnal heat stress (dHS). Eighteen Holstein and four Jersey heifers (5–6 months of age; d1 BW=205±9 kg) were assigned to two dietary treatments (n = 11) based on breed and age; 1) a basal TMR diet (CTL), 2) CTL supplemented with 0.25 g/head/d of a proprietary blend of phytogenics (PFA; BIOMIN America, Inc., Overland Park, KS). Heifers were housed individually and fed their respective treatments for 14d prior to dHS (d-14-1), subjected dHS (d1-7), and followed through a recovery period (d8-11). Weights were collected at d1 (baseline), d7 (end of dHS), and d11 (end of recovery). The temperature set point was assigned at 33°C from 0900 to 2100 h and allowed to equilibrate with outside temperature during night (24°C) for a total of 7d dHS. Total DMI (tDMI) and DMI from 0900 to 2100 h (hsDMI) were recorded daily. Serum was collected at d1, 2, 7 and 11 to determine effect of treatment on markers of oxidation, inflammation, and stress. Treatment effects were analyzed using PROC MIXED in SAS with treatment and time as fixed effects and heifer as a random effect. Temperature humidity index during dHS was greater during the day (84.5) versus night (73.3). There were no treatment differences (P&gt;0.05) in d 0–11 on ADG, ADFI, or GF between treatments. However, PFA numerically increased hsDMI, reduced (P&lt; 0.05) haptoglobin and tended to reduce (P&lt; 0.10) lipopolysaccharide binding protein compared with CTL. Overall, dietary PFA may be a potential strategy to mitigate the stresses that heifers experience during dHS.


1988 ◽  
Vol 16 (3) ◽  
pp. 292-298 ◽  
Author(s):  
D. W. Blake ◽  
G. Donnan ◽  
J. Novella ◽  
C. Hackman

The cardiovascular effects of intravenous sedation were studied in fifty patients after spinal anaesthesia for lower limb or pelvic surgery. Twenty patients received propofol (mean dosage 74 (SD 4) μg/kg/min for 0–20 minutes and 51 (SD 7) μg/kg/min for 20–40 minutes), twenty received midazolam (35 μg/kg + 2.54 (SD 0.2) μg/kg/min for 0–20 minutes and 1.35 (SD 0.2) μg/kg/min for 20–40 minutes) and ten patients received saline infusion only. The forearm vasoconstriction in response to the spinal anaesthesia was measured by strain gauge plethysmography. Spinal anaesthesia lowered systolic and diastolic blood pressure by 18 (SED 4) mmHg and 9 (SED 2) mmHg respectively. (SED = standard error of the difference.) This was associated with a 32% decrease in mean forearm blood flow. Propofol and midazolam caused similar additional reductions in systolic and diastolic blood pressure (10 (SED 4) mmHg and 4 (SED 2) mmHg) and a decrease in heart rate (P< 0.005), but forearm vasoconstriction was not altered. In the control group, however, forearm vasoconstriction increased during 40 minutes in theatre (P<0.05). Recovery from propofol was far more rapid than after midazolam and was virtually complete in ten minutes. This was reflected by an increase in blood pressure and in forearm vasoconstriction in the recovery period.


2019 ◽  
Vol 46 (6) ◽  
pp. 555 ◽  
Author(s):  
Milena T. Gerganova ◽  
Aygyun K. Faik ◽  
Maya Y. Velitchkova

The kinetics of photoinhibition in detached leaves from tomato plants (Solanium lycopersicum L. cv. M82) grown for 6 days under different combinations of optimal and moderately high temperature and optimal and high light intensity were studied. The inhibition of PSII was evaluated by changes in maximal quantum yield, the coefficient of photochemical quenching and the quantum yield of PSII. The changes of PSI activity was estimated by the redox state of P700. The involvement of different possible protective processes was checked by determination of nonphotochemical quenching and cyclic electron flow around PSI. To evaluate to what extent the photosynthetic apparatus and its response to high light treatment was affected by growth conditions, the kinetics of photoinhibition in isolated thylakoid membranes were also studied. The photochemical activities of both photosystems and changes in the energy distribution and interactions between them were evaluated by means of a Clark electrode and 77 K fluorescence analysis. The data showed an increased tolerance to photoinhibition in plants grown under a combination of moderately high temperature and light intensity, which was related to the stimulation of cyclic electron flow, PSI activity and rearrangements of pigment–protein complexes, leading to a decrease in the excitation energy delivered to PSII.


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