scholarly journals Physiological adaptations of leaf litter microbial communities to long-term drought

2019 ◽  
Author(s):  
Ashish A. Malik ◽  
Tami Swenson ◽  
Claudia Weihe ◽  
Eric Morrison ◽  
Jennifer B. H. Martiny ◽  
...  
Keyword(s):  
Drought Stress ◽  
Microbial Communities ◽  
Stress Tolerance ◽  
Functional Response ◽  
Leaf Litter ◽  
Compatible Solutes ◽  
Resource Acquisition ◽  
Physiological Adaptations ◽  
Grass Litter

AbstractDrought represents a significant stress to soil microorganisms and is known to reduce microbial activity and organic matter decomposition in Mediterranean ecosystems. However, we still lack a detailed understanding of the drought stress adaptations of microbial decomposers. We hypothesised that drought causes greater microbial allocation to stress tolerance relative to growth pathways. Here we present metatranscriptomic and metabolomic data on the physiological response ofin situmicrobial communities on plant leaf litter to long-term drought and pulse wetting in Californian grass and shrub ecosystems. Wetting litter after a long dry summer caused only subtle shifts in gene expression. On grass litter, communities from the decade-long ambient and reduced precipitation treatments had distinct functional profiles. The most discernable physiological adaptations to drought were production or uptake of compatible solutes to maintain cellular osmotic balance, and synthesis of capsular and extracellular polymeric substances as a mechanism to retain water. The results show a clear functional response to drought in grass litter communities with greater allocation to survival relative to growth that could affect decomposition under drought. In contrast, communities on chemically more diverse and complex shrub litter had smaller physiological differences in response to long-term drought but higher investment in resource acquisition traits across treatments, suggesting that the functional response to drought is constrained by substrate quality. Our findings suggest, for the first time in a field setting, a trade-off between microbial drought stress tolerance, resource acquisition and growth traits in leaf litter microbial communities.

Linking microbial communities to soil carbon cycling under anthropogenic change using a trait-based framework

2020 ◽  
Author(s):  
Ashish Malik ◽  
Robert Griffiths ◽  
Steven Allison
Keyword(s):  
Drought Stress ◽  
Microbial Communities ◽  
Soil Carbon ◽  
Stress Tolerance ◽  
Carbon Storage ◽  
Resource Availability ◽  
Growth Yield ◽  
Resource Acquisition ◽  
Anthropogenic Change ◽  
Trade Offs

<p>Microbial physiology may be critical for projecting future changes in soil carbon. Still, predicting the ecosystem implications of microbial processes remains a challenge. We argue that this challenge can be met by identifying microbial life history strategies based on their phenotypic characteristics, or traits, and representing these strategies in models simulating different environmental conditions. By adapting several theories from macroecology, we define microbial high yield (Y), resource acquisition (A), and stress tolerance (S) strategies. Using multi-omics and carbon stable isotope probing tools, we empirically validated our Y-A-S framework by studying variations in community traits along gradients of resource availability and abiotic conditions arising from anthropogenic change. Across a Britain-wide land use intensity gradient, we used isotope tracing and metaproteomics to show that microbial resource acquisition and stress tolerance traits trade off with growth yield measured as carbon use efficiency. Reduced community growth yield with intensification was linked to decreased microbial biomass and increased biomass-specific respiration which subsequently translated into lower organic carbon storage in such soil systems. We concluded that less-intensive management practices have more potential for carbon storage through increased microbial growth yield by greater channelling of substrates into biomass synthesis. In Californian grass and shrub ecosystems, we used metatranscriptomics and metabolomics to infer traits of in situ microbial communities on plant leaf litter in response to long-term drought. This experimental set-up provided gradients of resource availability and water stress. We observed that drought causes greater microbial allocation to stress tolerance. The most discernable physiological adaptations to drought in litter communities were production or uptake of compatible solutes like trehalose and ectoine as well as inorganic ions to maintain cellular osmotic balance. Grass communities also increased expression of genes for synthesis of capsular and extracellular polymeric substances possibly as a mechanism to retain water. These results showed a clear functional response to drought in grass litter communities with greater allocation to survival relative to growth that reduced decomposition under drought. In contrast, communities on chemically complex shrub litter had smaller differences in gene expression and metabolite profiles in response to drought, suggesting that the drought stress response is constrained by litter chemistry which also reduces decomposition rates. Overall, our findings suggest trade-offs between drought stress tolerance, resource acquisition and growth yield in communities across different ecosystems. These empirical studies demonstrate how trade-offs in key microbial traits can have consequences on soil carbon decomposition and storage. We recommend the use of our Y-A-S framework in experimental and modelling studies to mechanistically link microbial communities to system-level processes.</p>

scholarly journals Drought Stress Impacts on Plants and Different Approaches to Alleviate Its Adverse Effects

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 259
Author(s):  
Mahmoud F. Seleiman ◽  
Nasser Al-Suhaibani ◽  
Nawab Ali ◽  
Mohammad Akmal ◽  
Majed Alotaibi ◽  
...  
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Adverse Effects ◽  
Stress Tolerance ◽  
Hormonal Regulation ◽  
Plant Biomass ◽  
Compatible Solutes ◽  
Plant Tolerance ◽  
Water Stress Tolerance ◽  
Adaptation Mechanisms

Drought stress, being the inevitable factor that exists in various environments without recognizing borders and no clear warning thereby hampering plant biomass production, quality, and energy. It is the key important environmental stress that occurs due to temperature dynamics, light intensity, and low rainfall. Despite this, its cumulative, not obvious impact and multidimensional nature severely affects the plant morphological, physiological, biochemical and molecular attributes with adverse impact on photosynthetic capacity. Coping with water scarcity, plants evolve various complex resistance and adaptation mechanisms including physiological and biochemical responses, which differ with species level. The sophisticated adaptation mechanisms and regularity network that improves the water stress tolerance and adaptation in plants are briefly discussed. Growth pattern and structural dynamics, reduction in transpiration loss through altering stomatal conductance and distribution, leaf rolling, root to shoot ratio dynamics, root length increment, accumulation of compatible solutes, enhancement in transpiration efficiency, osmotic and hormonal regulation, and delayed senescence are the strategies that are adopted by plants under water deficit. Approaches for drought stress alleviations are breeding strategies, molecular and genomics perspectives with special emphasis on the omics technology alteration i.e., metabolomics, proteomics, genomics, transcriptomics, glyomics and phenomics that improve the stress tolerance in plants. For drought stress induction, seed priming, growth hormones, osmoprotectants, silicon (Si), selenium (Se) and potassium application are worth using under drought stress conditions in plants. In addition, drought adaptation through microbes, hydrogel, nanoparticles applications and metabolic engineering techniques that regulate the antioxidant enzymes activity for adaptation to drought stress in plants, enhancing plant tolerance through maintenance in cell homeostasis and ameliorates the adverse effects of water stress are of great potential in agriculture.

Contrapuntal role of ABA: Does it mediate stress tolerance or plant growth retardation under long-term drought stress?

Gene ◽  
2012 ◽  
Vol 506 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Nese Sreenivasulu ◽  
Vokkaliga T. Harshavardhan ◽  
Geetha Govind ◽  
Christiane Seiler ◽  
Ajay Kohli
Keyword(s):  
Drought Stress ◽  
Plant Growth ◽  
Stress Tolerance ◽  
Growth Retardation

scholarly journals Exploring Trait Trade-Offs for Fungal Decomposers in a Southern California Grassland

2021 ◽  
Vol 12 ◽  
Author(s):  
Charlotte J. Alster ◽  
Steven D. Allison ◽  
Sydney I. Glassman ◽  
Adam C. Martiny ◽  
Kathleen K. Treseder
Keyword(s):  
Drought Stress ◽  
Stress Tolerance ◽  
Southern California ◽  
Extracellular Enzymes ◽  
Growth Yield ◽  
Resource Acquisition ◽  
Supporting Evidence ◽  
Drought Stress Tolerance ◽  
Trade Offs ◽  
California Grassland

Fungi are important decomposers in terrestrial ecosystems, so their responses to climate change might influence carbon (C) and nitrogen (N) dynamics. We investigated whether growth and activity of fungi under drought conditions were structured by trade-offs among traits in 15 fungal isolates from a Mediterranean Southern California grassland. We inoculated fungi onto sterilized litter that was incubated at three moisture levels (4, 27, and 50% water holding capacity, WHC). For each isolate, we characterized traits that described three potential lifestyles within the newly proposed “YAS” framework: growth yield, resource acquisition, and stress tolerance. Specifically, we measured fungal hyphal length per unit litter decomposition for growth yield; the potential activities of the extracellular enzymes cellobiohydrolase (CBH), β-glucosidase (BG), β-xylosidase (BX), and N-acetyl-β-D-glucosaminidase (NAG) for resource acquisition; and ability to grow in drought vs. higher moisture levels for drought stress tolerance. Although, we had hypothesized that evolutionary and physiological trade-offs would elicit negative relationships among traits, we found no supporting evidence for this hypothesis. Across isolates, growth yield, drought stress tolerance, and extracellular enzyme activities were not significantly related to each other. Thus, it is possible that drought-induced shifts in fungal community composition may not necessarily lead to changes in fungal biomass or decomposer ability in this arid grassland.

Assessment of rice (Oryza sativa L.) genotypes for drought stress tolerance using morpho-physiological indices as a screening technique

2020 ◽  
Vol 53 (1) ◽  
Author(s):  
Asma Asma ◽  
Iqbal Hussain ◽  
Muhammad Yasin Ashraf ◽  
Muhammad Arslan Ashraf ◽  
Rizwan Rasheed ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Drought Stress ◽  
Stress Tolerance ◽  
Oryza Sativa L ◽  
Screening Technique ◽  
Drought Stress Tolerance ◽  
Physiological Indices

Use Of Tai Chi Elements To Increase Respiratory Amplitude

2019 ◽  
pp. 11-20
Author(s):  
Mihai-Alexandru Citea ◽  
Marius Neculaes
Keyword(s):  
High Performance ◽  
Tai Chi ◽  
Sports Club ◽  
Optimal Functioning ◽  
Physiological Adaptations ◽  
Competitive Activity ◽  
Abdominal Breathing ◽  
Study Participants ◽  
Different Levels

High performance sport has a major impact on the physiological adaptations of the respiratory system. The importance of the optimal functioning of this system is essential to achieve top results in high performance sport but also in maintaining a long term health status. Science journals present numerous studies that highlight the benefits of practicing Tai Chi on the general population, with effects ranging from improving cardiac function, to influencing the immune system. The purpose of this study is to identify whether by practicing Tai Chi forms a athlete can change their breathing pattern and develop their respiratory amplitude. The subjects of the study were 22 fencing practitioners, accredited at the Iași Municipal Sports Club (C.S.M. Iași), aged between 14 and 18 years, with over 3 years of competitive activity. Materials and method: The study participants were evaluated initially and at the end of 7 months of practice. The frequency was 3 sessions per week, and the duration of each session was 20-30 minutes. The evaluation consisted in measuring the circumference of the thorax at 3 different levels: subaxillary, medial thorax (T6-T7) and lower rib (diaphragmatic) in maximal inspiration and expiration. Conclusions: A constant evolution is observed in most of the exposed cases. In cases where this evolution is not visible, a change in the breathing mode can be noticed, transforming from an upper rib breathing into a thoracic or abdominal breathing. With the exception of one case, all subjects had an improvement of the value in the lower rib level.

Precursor processing by SBT3.8 and phytosulfokine signaling contribute to drought stress tolerance in Arabidopsis

2021 ◽  
Author(s):  
Nils Stührwohldt ◽  
Eric Bühler ◽  
Margret Sauter ◽  
Andreas Schaller
Keyword(s):  
Drought Stress ◽  
Osmotic Stress ◽  
Stress Tolerance ◽  
Serine Proteases ◽  
Loss Of Function ◽  
Lateral Root Development ◽  
Osmotic Stress Tolerance ◽  
Stress Symptoms ◽  
C Terminus ◽  
Peptide Precursor

Abstract Increasing drought stress poses a severe threat to agricultural productivity. Plants, however, evolved numerous mechanisms to cope with such environmental stress. Here we report that the stress-induced production of a peptide signal contributes to stress tolerance. The expression of phytosulfokine (PSK) peptide precursor genes, and transcripts of three subtilisin-like serine proteases, SBT1.4, SBT3.7 and SBT3.8 were found to be up-regulated in response to osmotic stress. Stress symptoms were enhanced in sbt3.8 loss-of-function mutants and could be alleviated by PSK treatment. Osmotic stress tolerance was improved in plants overexpressing the precursor of PSK1 (proPSK1) or SBT3.8 resulting in higher fresh weight and improved lateral root development in the transgenic compared to wild-type plants. We further showed that SBT3.8 is involved in the biogenesis of the bioactive PSK peptide. ProPSK1 was cleaved by SBT3.8 at the C-terminus of the PSK pentapeptide. Processing by SBT3.8 depended on the aspartic acid residue directly following the cleavage site. ProPSK1 processing was impaired in the sbt3.8 mutant. The data suggest that increased expression in response to osmotic stress followed by the post-translational processing of proPSK1 by SBT3.8 leads to the production of PSK as a peptide signal for stress mitigation.

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