Oxidative stress is commonly induced when plants are grown under high temperature (HT) stress conditions. Selenium often acts as an antioxidant in plants; however, its role under HT-induced oxidative ...stress is not definite. We hypothesize that selenium application can partly alleviate HT-induced oxidative stress and negative impacts of HT on physiology, growth and yield of grain sorghum
Sorghum bicolor (L.) Moench. Objectives of this study were to investigate the effects of selenium on (a) leaf photosynthesis, membrane stability and antioxidant enzymes activity and (b) grain yield and yield components of grain sorghum plants grown under HT stress in controlled environments. Plants were grown under optimal temperature (OT; 32/22
°C daytime maximum/nighttime minimum) from sowing to 63 days after sowing (DAS). All plants were foliar sprayed with sodium selenate (75
mg
L
−1) at 63 DAS, and HT stress (40/30
°C) was imposed from 65 DAS through maturity. Data on physiological, biochemical and yield traits were measured. High temperature stress decreased chlorophyll content, chlorophyll
a fluorescence, photosynthetic rate and antioxidant enzyme activities and increased oxidant production and membrane damage. Decreased antioxidant defense under HT stress resulted in lower grain yield compared with OT. Application of selenium decreased membrane damage by enhancing antioxidant defense resulting in higher grain yield. The increase in antioxidant enzyme activities and decrease in reactive oxygen species (ROS) content by selenium was greater in HT than in OT. The present study suggests that selenium can play a protective role during HT stress by enhancing the antioxidant defense system.
► High temperature stress increases oxidative damage in leaves. ► High temperature stress decreased antioxidant enzyme activity. ► High temperature stress decreased photosynthetic rates and grain yield. ► Foliar application of Se enhanced antioxidant defense system. ► Selenium can play a protective role during high temperature stress conditions.
Key message
We describe here the recent developments about the involvement of diverse stress-related proteins in sensing, signaling, and defending the cells in plants in response to drought or/and ...heat stress.
In the current era of global climate drift, plant growth and productivity are often limited by various environmental stresses, especially drought and heat. Adaptation to abiotic stress is a multigenic process involving maintenance of homeostasis for proper survival under adverse environment. It has been widely observed that a series of proteins respond to heat and drought conditions at both transcriptional and translational levels. The proteins are involved in various signaling events, act as key transcriptional activators and saviors of plants under extreme environments. A detailed insight about the functional aspects of diverse stress-responsive proteins may assist in unraveling various stress resilience mechanisms in plants. Furthermore, by identifying the metabolic proteins associated with drought and heat tolerance, tolerant varieties can be produced through transgenic/recombinant technologies. A large number of regulatory and functional stress-associated proteins are reported to participate in response to heat and drought stresses, such as protein kinases, phosphatases, transcription factors, and late embryogenesis abundant proteins, dehydrins, osmotins, and heat shock proteins, which may be similar or unique to stress treatments. Few studies have revealed that cellular response to combined drought and heat stresses is distinctive, compared to their individual treatments. In this review, we would mainly focus on the new developments about various stress sensors and receptors, transcription factors, chaperones, and stress-associated proteins involved in drought or/and heat stresses, and their possible role in augmenting stress tolerance in crops.
Heat stress (HS) is one of the major abiotic stresses affecting the production and quality of wheat. Rising temperatures are particularly threatening to wheat production. A detailed overview of ...morpho-physio-biochemical responses of wheat to HS is critical to identify various tolerance mechanisms and their use in identifying strategies to safeguard wheat production under changing climates. The development of thermotolerant wheat cultivars using conventional or molecular breeding and transgenic approaches is promising. Over the last decade, different omics approaches have revolutionized the way plant breeders and biotechnologists investigate underlying stress tolerance mechanisms and cellular homeostasis. Therefore, developing genomics, transcriptomics, proteomics, and metabolomics data sets and a deeper understanding of HS tolerance mechanisms of different wheat cultivars are needed. The most reliable method to improve plant resilience to HS must include agronomic management strategies, such as the adoption of climate-smart cultivation practices and use of osmoprotectants and cultured soil microbes. However, looking at the complex nature of HS, the adoption of a holistic approach integrating outcomes of breeding, physiological, agronomical, and biotechnological options is required. Our review aims to provide insights concerning morpho-physiological and molecular impacts, tolerance mechanisms, and adaptation strategies of HS in wheat. This review will help scientific communities in the identification, development, and promotion of thermotolerant wheat cultivars and management strategies to minimize negative impacts of HS.
Prior studies have evaluated the percentage of cancer patients with advanced or metastatic cancer who are eligible for and respond to genome-targeted therapy, but since that publication, the number ...of Food and Drug Administration (FDA) approvals for drugs targeting genetic indications has grown rapidly. We sought to update the estimates of both eligibility for and response to genome-targeted and genome-informed therapies in US cancer patients for FDA-approved drugs to reflect estimates as of 2020.
We used mortality data from the American Cancer Society to estimate eligibility for these drugs, based on prevalence statistics from the published literature. We then multiplied eligibility by the response rate in the FDA label to generate an estimate for the percentage of US cancer patients who respond.
For genome-targeted therapy, we estimate that the eligibility increased from 5.13% in 2006 to 13.60% in 2020. For genome-targeted therapy, we estimate that the response increased from 2.73% in 2006 to 7.04% in 2020.
The percentage of US cancer patients who are eligible for and respond to genome-targeted therapy has increased over time. Most of the increase in eligibility for genome-targeted therapies was seen after 2018, whereas most of the increase in response was seen before 2018.
•We estimate that the response to genome-targeted therapy increased from 2.73% in 2006 to 7.04% in 2020.•The percentage of patients with cancer in the United States who responded to genome-targeted therapy was modest.•Most of the increase in response was seen before 2018, and most of the increase in eligibility after 2018.
Rapid increases in minimum night temperature than in maximum day temperature is predicted to continue, posing significant challenges to crop productivity. Rice and wheat are two major staples that ...are sensitive to high night‐temperature (HNT) stress. This review aims to (i) systematically compare the grain yield responses of rice and wheat exposed to HNT stress across scales, and (ii) understand the physiological and biochemical responses that affect grain yield and quality. To achieve this, we combined a synthesis of current literature on HNT effects on rice and wheat with information from a series of independent experiments we conducted across scales, using a common set of genetic materials to avoid confounding our findings with differences in genetic background. In addition, we explored HNT‐induced alterations in physiological mechanisms including carbon balance, source–sink metabolite changes and reactive oxygen species. Impacts of HNT on grain developmental dynamics focused on grain‐filling duration, post‐flowering senescence, changes in grain starch and protein composition, starch metabolism enzymes and chalk formation in rice grains are summarized. Finally, we highlight the need for high‐throughput field‐based phenotyping facilities for improved assessment of large‐diversity panels and mapping populations to aid breeding for increased resilience to HNT in crops.
Impact of high night temperature on grain yield and quality in field crops, captured across spatial scales, allows the identification of tolerant germplasm, traits and mechanisms from controlled environments that have relevance under field conditions.
Gene expression in endosperm-a seed tissue that mediates transfer of maternal resources to offspring-is under complex epigenetic control. We show here that plant-specific RNA polymerase IV (Pol IV) ...mediates parental control of endosperm gene expression. Pol IV is required for the production of small interfering RNAs that typically direct DNA methylation. We compared small RNAs (sRNAs), DNA methylation, and mRNAs in Arabidopsis thaliana endosperm from heterozygotes produced by reciprocally crossing wild-type (WT) plants to Pol IV mutants. We find that maternally and paternally acting Pol IV induce distinct effects on endosperm. Loss of maternal or paternal Pol IV impacts sRNAs and DNA methylation at different genomic sites. Strikingly, maternally and paternally acting Pol IV have antagonistic impacts on gene expression at some loci, divergently promoting or repressing endosperm gene expression. Antagonistic parent-of-origin effects have only rarely been described and are consistent with a gene regulatory system evolving under parental conflict.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the present study, the effect of Zr addition on the mechanical properties of arc melted hypoeutectic Nb−16 at. %Si alloy has been investigated. The alloys were characterized by scanning electron ...microscopy (SEM), electron back scattered diffraction (EBSD), hardness test, nanoindentation test, compression test and three point bend test. The desirable phase α−Nb5Si3 phase could be obtained in alloys containing 4 at. % or more Zr. Nanoindentation results showed that the elastic modulus of Nbss phase is not significantly influenced by Zr additions whereas elastic modulus of Nb3Si and α−Nb5Si3phases are considerably improved by Zr additions. The strength, plasticity and room temperature fracture toughness of the alloys are significantly increased with Zr addition. The maximum compressive strength of 2160 ± 80 MPa, plastic strain of 2.6 ± 0.2% and fracture toughness of 14.3 ± 0.3MPam1/2are achieved in alloy with 4 at.% Zr.
This paper highlights the quality and impact of the COSMIC-2 bending angle through an Observation System Experiment, using a hybrid Gridpoint Statistical Interpolation - 4 Dimensional Ensemble ...Variational analysis scheme. The data quality is assessed by comparing it with the model's background field. Analysis and background field that fit to temperature, humidity and wind components from radiosondes are verified, and the impact over model forecasts is evaluated using various metrics. There is an overall improvement, especially over the tropical region, where consistent and statistically significant positive impact is observed over the troposphere extending up through the lower to the middle stratosphere. A case study of the Super Cyclonic Storm AMPHAN showed minor improvement in central pressure and maximum 10 m wind speed. Reduction in the direct positional error of the cyclone track showed improvement in the analysis.
Terminal droughts, along with high temperatures, are becoming more frequent to strongly influence the seed development in cool‐season pulses like lentil. In the present study, the lentil plants ...growing outdoors under natural environment were subjected to following treatments at the time of seed filling till maturity: (a) 28/23 °C day/night temperature as controls; (b) drought stressed, plants maintained at 50% field capacity, under the same growth conditions as in a; (c) heat stressed, 33/28 °C day/night temperature, under the same growth conditions as in a; and (d) drought + heat stressed, plants at 50% field capacity, 33/28 °C day/night temperature, under the same growth conditions as in (a). Both heat and drought resulted in marked reduction in the rate and duration of seed filling to decrease the final seed size; drought resulted in more damage than heat stress; combined stresses accentuated the damage to seed starch, storage proteins and their fractions, minerals, and several amino acids. Comparison of a drought‐tolerant and a drought‐sensitive genotype indicated the former type showed significantly less damage to various components of seeds, under drought as well as heat stress suggesting a cross tolerance, which was linked to its (drought tolerant) better capacity to retain more water in leaves and hence more photo‐assimilation ability, compared with drought‐sensitive genotype.
Lentil is a cool‐season food legume, which is strongly influenced by terminal droughts associated with heat stress at the time of seed filling. The present study showed that these two stresses, especially in combination would diminish the seed yields severely and would also result in poor‐quality seeds, deficient in starch, proteins, and minerals. Drought tolerant lentil genotypes might prove to be promising under combined stress treatments.
PDF
