scholarly journals Plant Hosts Modify Belowground Microbial Community Response to Extreme Drought

mSystems ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Allison M. Veach ◽  
Huaihai Chen ◽  
Zamin K. Yang ◽  
Audrey D. Labbe ◽  
Nancy L. Engle ◽  
...  
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Microbial Activity ◽  
Stress Responses ◽  
Bacterial Community Composition ◽  
Recovery Period ◽  
Community Response ◽  
Extreme Drought ◽  
Soil Microbiome ◽  
Belowground Interactions

ABSTRACT Drought stress negatively impacts microbial activity, but the magnitude of stress responses is likely dependent on a diversity of belowground interactions. Populus trichocarpa individuals and no-plant bulk soils were exposed to extended drought (∼0.03% gravimetric water content [GWC] after 12 days), rewet, and a 12-day “recovery” period to determine the effects of plant presence in mediating soil microbiome stability to water stress. Plant metabolomic analyses indicated that drought exposure increased host investment in C and N metabolic pathways (amino acids, fatty acids, phenolic glycosides) regardless of recovery. Several metabolites positively correlated with root-associated microbial alpha-diversity, but not those of soil communities. Soil bacterial community composition shifted with P. trichocarpa presence and with drought relative to irrigated controls, whereas soil fungal composition shifted only with plant presence. However, root fungal communities strongly shifted with drought, whereas root bacterial communities changed to a lesser degree. The proportion of bacterial water-stress opportunistic operational taxonomic units (OTUs) (enriched counts in drought) was high (∼11%) at the end of drying phases and maintained after rewet and recovery phases in bulk soils, but it declined over time in soils with plants present. For root fungi, opportunistic OTUs were high at the end of recovery in drought treatments (∼17% abundance), although relatively not responsive in soils, particularly planted soils (<0.5% abundance for sensitive or opportunistic). These data indicate that plants modulate soil and root-associated microbial drought responses via tight plant-microbe linkages during extreme drought scenarios, but trajectories after extreme drought vary with plant habitat and microbial functional groups. IMPORTANCE Climate change causes significant alterations in precipitation and temperature regimes that are predicted to become more extreme throughout the next century. Microorganisms are important members within ecosystems, and how they respond to these changing abiotic stressors has large implications for the functioning of ecosystems, the recycling of nutrients, and the health of the aboveground plant community. Drought stress negatively impacts microbial activity, but the magnitude of this stress response may be dependent on above- and belowground interactions. This study demonstrates that beneficial associations between plants and microbes can enhance tolerance to abiotic stress.

scholarly journals Analysis of Non-Structural Carbohydrates and Xylem Anatomy of Leaf Petioles Offers New Insights in the Drought Response of Two Grapevine Cultivars

2020 ◽  
Vol 21 (4) ◽  
pp. 1457 ◽  
Author(s):  
Rachele Falchi ◽  
Elisa Petrussa ◽  
Enrico Braidot ◽  
Paolo Sivilotti ◽  
Francesco Boscutti ◽  
...  
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Stress Response ◽  
Stress Responses ◽  
Cabernet Sauvignon ◽  
Drought Response ◽  
Xylem Anatomy ◽  
Anatomical Analysis ◽  
Starch Mobilization ◽  
Xylem Conduits

In grapevine, the anatomy of xylem conduits and the non-structural carbohydrates (NSCs) content of the associated living parenchyma are expected to influence water transport under water limitation. In fact, both NSC and xylem features play a role in plant recovery from drought stress. We evaluated these traits in petioles of Cabernet Sauvignon (CS) and Syrah (SY) cultivars during water stress (WS) and recovery. In CS, the stress response was associated to NSC consumption, supporting the hypothesis that starch mobilization is related to an increased supply of maltose and sucrose, putatively involved in drought stress responses at the xylem level. In contrast, in SY, the WS-induced increase in the latter soluble NSCs was maintained even 2 days after re-watering, suggesting a different pattern of utilization of NSC resources. Interestingly, the anatomical analysis revealed that conduits are constitutively wider in SY in well-watered (WW) plants, and that water stress led to the production of narrower conduits only in this cultivar.

scholarly journals Studies on the Accumulation of Drought-Induced Boiling Soluble Proteins (Hydrophilins) at Vegetative and Reproductive Phases of Drought Tolerant and Susceptible Cultivars of Triticum aestivum

2014 ◽  
Vol 6 (2) ◽  
pp. 225-236
Author(s):  
Gurmeen RAKHRA ◽  
Arun Dev SHARMA ◽  
Jatinder SINGH
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Stress Responses ◽  
Blot Analysis ◽  
Soluble Proteins ◽  
Dependent Manner ◽  
Water Stress Tolerance ◽  
Drought Tolerant ◽  
Boiling Soluble Proteins

Drought is one of the major environmental constraints affecting the crops worldwide. Expression of boiling soluble proteins (BSPs) is of paramount importance, because they play important roles in the water stress responses and also in plant metabolism. In this study, the effect of drought on BSPs at vegetative (shoots) and reproductive (seeds) phases of drought tolerant (cv. ‘PBW 527’) and drought susceptible (cv. ‘PBW 343’) cultivars of Triticumaestivum were carried at three different developmental stages. The boiling soluble protein profiles of shoots and seeds were outlined via SDS-PAGE followed by immune-blot analysis using anti-HSP, anti-APase, anti-LEA, anti-SOD, anti-AQUA and anti-CAT antibodies. Western blot analysis revealed that expression of BSPs was modulated differentially in a stress, tissue, developmental stage and cultivar dependent manner. For instance, enhanced expression of seeds BSPs (APase, LEA, CAT, AQUA) was observed in the tolerant cv. ‘PBW 527’ after drought stress. However, no such enhancement was observed in the susceptible cultivar. Similarly, in shoots of cv. ‘PBW 527’, a substantial increase of BSP (SOD) expression was established after drought stress treatment, indicating their role in drought stress adaptation. Further, to gain an insight into the role of BSPs, a time course pre- and post-stress kinetic studies were also conducted in the seeds of tolerant and susceptible wheat cultivars. Based upon the observations, the possible role of boiling soluble proteins (hydrophilins) in water stress tolerance is discussed.

scholarly journals Mitigating Effect of Glycinebetaine Pretreatment on Drought Stress Responses of Creeping Bentgrass

HortScience ◽  
2018 ◽  
Vol 53 (12) ◽  
pp. 1842-1848 ◽  
Author(s):  
Lu Gan ◽  
Xunzhong Zhang ◽  
Silu Liu ◽  
Shuxia Yin
Keyword(s):  
Gene Expression ◽  
Water Stress ◽  
Drought Stress ◽  
Chlorophyll Content ◽  
Stress Responses ◽  
Creeping Bentgrass ◽  
External Application ◽  
Antioxidant Enzyme System ◽  
Turf Quality ◽  
Mda Content

Turfgrass performance under drought stress is impeded by plant water deficit and oxidative damage, which might be improved by the external application of osmoprotectants. Creeping bentgrass (Agrostis stolonifera L.) is a valuable species for low-cut golf surfaces as a result of its high density and fine texture. However, weak tolerance to drought stress is a primary shortcoming. In this study, the effect of exogenous glycinebetaine (GB) pretreatment on mitigating the damage from drought stress in creeping bentgrass cultivar ‘T-1’ was evaluated. Pieces of creeping bentgrass sod were subjected to four treatments: 1) well-watered control, 2) well watered and sprayed with 100 mm GB, 3) drought stress, and 4) drought stress and sprayed with 100 mm GB. Drought stress resulted in a remarkable decrease in turf quality (TQ), relative water content (RWC), and chlorophyll content, with significant increases in superoxide anion content (O2–), malondialdehyde (MDA) content, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activity. In contrast, pretreatment with 100 mm GB decreased the O2– and MDA content in water-stressed plants, and increased turf quality, chlorophyll content, SOD, CAT, and POD activity. Meanwhile, the expression level of the psbA, SAMS4, CMO, and ACS1 genes in leaf samples collected during the drought-stress stage was elevated in GB pretreatment. Notably, SAMS4 gene expression in GB pretreatment was significantly greater than in the untreated GB groups subjected to water stress. These results suggested that GB could mitigate the adverse effect of water stress on creeping bentgrass. The amelioration related strongly to the maintenance of the antioxidant enzyme system, accumulated endogenous compatible metabolites, and the elevation of gene expression levels. These findings lead us to conclude that GB pretreatment could be used as an ameliorative agent for creeping bentgrass against the deleterious effects of water stress.

scholarly journals Shared genetic architecture underlying root metaxylem phenotypes under drought stress in cereals

2020 ◽  
Author(s):  
Stephanie P. Klein ◽  
Jenna E. Reeger ◽  
Shawn M. Kaeppler ◽  
Kathleen M. Brown ◽  
Jonathan P. Lynch
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Candidate Genes ◽  
Stress Responses ◽  
Genetic Architecture ◽  
Association Studies ◽  
Multiple Root ◽  
Stress Conditions ◽  
Genome Wide Association Studies ◽  
New Strategy

AbstractRoot metaxylem are phenotypically diverse structures whose function is related to their anatomy, particularly under drought stress. Much research has dissected the genetic machinery underlying metaxylem phenotypes in dicots, but monocots are relatively unexplored. In maize (Zea mays), a robust pipeline integrated a GWAS of root metaxylem phenes under well-watered and water stress conditions with a gene co-expression network to identify candidate genes most likely to impact metaxylem phenotypes. We identified several promising candidate genes in 14 gene co-expression modules inferred to be functionally relevant to xylem development. We also identified five gene candidates that co-localized in multiple root metaxylem phenes in both well-watered and water stress conditions. Using a rice GWAS conducted in parallel, we detected overlapping genetic architecture influencing root metaxylem phenotypes by identifying eight pairs of syntenic candidate genes significantly associated with metaxylem phenes. There is evidence that the genes of these syntenic pairs may be involved in biosynthetic processes related to the cell wall, hormone signaling, oxidative stress responses, and drought responses. Our study demonstrates a powerful new strategy for identifying promising gene candidates and suggests several gene candidates that may enhance our understanding of vascular development and responses to drought in cereals.One sentence summaryCross-species genome-wide association studies and a gene coexpression network identified genes associated with root metaxylem phenotypes in maize under water stress and non-stress and rice.

scholarly journals Genetically Different Isolates of the Arbuscular Mycorrhizal Fungus Rhizophagus irregularis Induce Differential Responses to Stress in Cassava

2020 ◽  
Vol 11 ◽  
Author(s):  
Ricardo Peña ◽  
Chanz Robbins ◽  
Joaquim Cruz Corella ◽  
Moses Thuita ◽  
Cargele Masso ◽  
...  
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Stress Responses ◽  
Mycorrhizal Fungi ◽  
Crop Yields ◽  
Physiological Stress ◽  
Physiological Responses ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Field Conditions

Water scarcity negatively impacts global crop yields and climate change is expected to greatly increase the severity of future droughts. The use of arbuscular mycorrhizal fungi (AMF) can potentially mitigate the effects of water stress in plants. Cassava is a crop that feeds approximately 800 million people daily. Genetically different isolates of the AMF R. irregularis as well as their clonal progeny have both been shown to greatly alter cassava growth in field conditions. Given that cassava experiences seasonal drought in many of the regions in which it is cultivated, we evaluated whether intraspecific variation in R. irregularis differentially alters physiological responses of cassava to water stress. In a first experiment, conducted in field conditions in Western Kenya, cassava was inoculated with two genetically different R. irregularis isolates and their clonal progeny. All cassava plants exhibited physiological signs of stress during the dry period, but the largest differences occurred among plants inoculated with clonal progeny of each of the two parental fungal isolates. Because drought had not been experimentally manipulated in the field, we conducted a second experiment in the greenhouse where cassava was inoculated with two genetically different R. irregularis isolates and subjected to drought, followed by re-watering, to allow recovery. Physiological stress responses of cassava to drought differed significantly between plants inoculated with the two different fungi. However, plants that experienced higher drought stress also recovered at a faster rate following re-watering. We conclude that intraspecific genetic variability in AMF significantly influences cassava physiological responses during water stress. This highlights the potential of using naturally existing variation in AMF to improve cassava tolerance undergoing water stress. However, the fact that clonal progeny of an AMF isolate can differentially affect how cassava copes with natural drought stress in field conditions, highlights the necessity to understand additional factors, beyond genetic variation, which can account for such large differences in cassava responses to drought.

Morphological, Physiological and Biochemical Responses of Poplar Plants to Drought Stress

2018 ◽  
Vol 5 (03) ◽  
Author(s):  
ARADHNA KUMARI ◽  
IM KHAN ◽  
ANIL KUMAR SINGH ◽  
SANTOSH KUMAR SINGH
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Biochemical Parameters ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Field Capacity ◽  
Drought Event ◽  
Total Biomass ◽  
Biochemical Responses ◽  
Physiological And Biochemical

Poplar clone Kranti was selected to assess the morphological, physiological and biochemical responses under drought at different levels of water stress, as it is a common clone used to be grown in Uttarakhand for making paper and plywood. The cuttings of Populus deltoides L. (clone Kranti) were exposed to four different watering regimes (100, 75, 50 and 25% of the field capacity) and changes in physiological and biochemical parameters related with drought tolerance were recorded. Alterations in physiological (i.e. decrease in relative water content) and biochemical parameters (i.e. increase in proline and soluble sugar content and build-up of malondialdehyde by-products) occurred in all the three levels of water stress, although drought represented the major determinant. Drought treatments (75%, 50% and 25% FC) decreased plant height, radial stem diameter, harvest index, total biomass content and RWC in all the three watering regimes compared to control (100% FC). Biochemical parameters like proline, soluble sugar and MDA content increased with severity and duration of stress, which helped plants to survive under severe stress. It was analyzed that for better wood yield poplar seedlings should avail either optimum amount of water (amount nearly equal to field capacity of soil) or maximum withdrawal up to 75% of field capacity up to seedling establishment period (60 days). Furthermore, this study manifested that acclimation to drought stress is related with the rapidity, severity, and duration of the drought event of the poplar species.

scholarly journals A microbiota–root–shoot circuit favours Arabidopsis growth over defence under suboptimal light

Nature Plants ◽  
2021 ◽  
Author(s):  
Shiji Hou ◽  
Thorsten Thiergart ◽  
Nathan Vannier ◽  
Fantin Mesny ◽  
Jörg Ziegler ◽  
...  
Keyword(s):  
Stress Responses ◽  
Photosynthetically Active Radiation ◽  
Bacterial Community Composition ◽  
Light Condition ◽  
Long Distance ◽  
Active Radiation ◽  
Light Manipulation ◽  
Growth Deficiency ◽  
Dependent Growth ◽  
Control Light

AbstractBidirectional root–shoot signalling is probably key in orchestrating stress responses and ensuring plant survival. Here, we show that Arabidopsis thaliana responses to microbial root commensals and light are interconnected along a microbiota–root–shoot axis. Microbiota and light manipulation experiments in a gnotobiotic plant system reveal that low photosynthetically active radiation perceived by leaves induces long-distance modulation of root bacterial communities but not fungal or oomycete communities. Reciprocally, microbial commensals alleviate plant growth deficiency under low photosynthetically active radiation. This growth rescue was associated with reduced microbiota-induced aboveground defence responses and altered resistance to foliar pathogens compared with the control light condition. Inspection of a set of A. thaliana mutants reveals that this microbiota- and light-dependent growth–defence trade-off is directly explained by belowground bacterial community composition and requires the host transcriptional regulator MYC2. Our work indicates that aboveground stress responses in plants can be modulated by signals from microbial root commensals.

scholarly journals Exogenous Application of Brassinosteroid 24-Norcholane 22(S)-23-Dihydroxy Type Analogs to Enhance Water Deficit Stress Tolerance in Arabidopsis thaliana

2021 ◽  
Vol 22 (3) ◽  
pp. 1158
Author(s):  
Katy Díaz ◽  
Luis Espinoza ◽  
Rodrigo Carvajal ◽  
Evelyn Silva-Moreno ◽  
Andrés F. Olea ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Drought Stress ◽  
Stress Tolerance ◽  
Water Deficit ◽  
Alternative Pathway ◽  
Recovery Period ◽  
Homogeneous Solution ◽  
Water Deficit Stress ◽  
Marker Genes ◽  
Exogenous Application

Brassinosteroids (BRs) are plant hormones that play an essential role in plant development and have the ability to protect plants against various environmental stresses, such as low and high temperature, drought, heat, salinity, heavy metal toxicity, and pesticides. Mitigation of stress effects are produced through independent mechanisms or by interaction with other important phytohormones. However, there are few studies in which this property has been reported for BRs analogs. Thus, in this work, the enhancement of drought stress tolerance of A. thaliana was assessed for a series of 2-deoxybrassinosteroid analogs. In addition, the growth-promoting activity in the Rice Lamina Inclination Test (RLIT) was also evaluated. The results show that analog 1 exhibits similar growth activity as brassinolide (BL; used as positive control) in the RLIT bioassay. Interestingly, both compounds increase their activities by a factor of 1.2–1.5 when they are incorporated to polymer micelles formed by Pluronic F-127. On the other hand, tolerance to water deficit stress of Arabidopsis thaliana seedlings was evaluated by determining survival rate and dry weight of seedlings after the recovery period. In both cases, the effect of analog 1 is higher than that exhibited by BL. Additionally, the expression of a subset of drought stress marker genes was evaluated in presence and absence of exogenous applied BRs. Results obtained by qRT-PCR analysis, indicate that transcriptional changes of AtDREBD2A and AtNCED3 genes were more significant in A. thaliana treated with analog 1 in homogeneous solution than in that treated with BL. These changes suggest the activation of alternative pathway in response to water stress deficit. Thus, exogenous application of BRs synthetic analogs could be a potential tool for improvement of crop production under stress conditions.

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