Influence of root growth and bacterial community in the rhizosphere of different root types of alfalfa under drought stress

2021 ◽  
Vol 41 (19) ◽  
Author(s):  
汪堃，南丽丽，师尚礼，郭全恩 WANG Kun
Keyword(s):  
Drought Stress ◽  
Bacterial Community ◽  
Root Growth ◽  
Root Types

scholarly journals Water uptake dynamics under progressive drought stress in diverse accessions of the OryzaSNP panel of rice (Oryza sativa)

2012 ◽  
Vol 39 (5) ◽  
pp. 402 ◽  
Author(s):  
Veeresh R. P. Gowda ◽  
Amelia Henry ◽  
Vincent Vadez ◽  
H. E. Shashidhar ◽  
Rachid Serraj
Keyword(s):  
Oryza Sativa ◽  
Drought Stress ◽  
Root Growth ◽  
Water Uptake ◽  
Root Length Density ◽  
Oryza Sativa L ◽  
Root Water Uptake ◽  
Snp Markers ◽  
Drought Response ◽  
Genotypic Differences

In addition to characterising root architecture, evaluating root water uptake ability is important for understanding drought response. A series of three lysimeter studies were conducted using the OryzaSNP panel, which consists of 20 diverse rice (Oryza sativa L.) genotypes. Large genotypic differences in drought response were observed in this genotype panel in terms of plant growth and water uptake. Total water uptake and daily water uptake rates in the drought-stress treatment were correlated with root length density, especially at depths below 30 cm. Patterns of water uptake among genotypes remained consistent throughout the stress treatments: genotypes that initially extracted more water were the same genotypes that extracted more water at the end of the study. These results suggest that response to drought by deep root growth, rather than a conservative soil water pattern, seems to be important for lowland rice. Genotypes in the O. sativa type aus group showed some of the greatest water uptake and root growth values. Since the OryzaSNP panel has been genotyped in detail with SNP markers, we expect that these results will be useful for understanding the genetics of rice root growth and function for water uptake in response to drought.

scholarly journals Phyllosphere community assembly and response to drought stress on common tropical and temperate forage grasses

2021 ◽  
Author(s):  
Emily K. Bechtold ◽  
Stephanie Ryan ◽  
Sarah E. Moughan ◽  
Ravi Ranjan ◽  
Klaus Nüsslein
Keyword(s):  
Microbial Community ◽  
Drought Stress ◽  
Bacterial Community ◽  
Community Assembly ◽  
Community Diversity ◽  
Grass Species ◽  
Severe Drought ◽  
Hormone Production ◽  
Plant Host ◽  
Bacterial Community Diversity

Grasslands represent a critical ecosystem important for global food production, soil carbon storage, and water regulation. Current intensification and expansion practices add to the degradation of grasslands and dramatically increase greenhouse gas emissions and pollution. Thus, new ways to sustain and improve their productivity are needed. Research efforts focus on the plant-leaf microbiome, or phyllosphere, because its microbial members impact ecosystem function by influencing pathogen resistance, plant hormone production, and nutrient availability through processes including nitrogen fixation. However, little is known about grassland phyllospheres and their response to environmental stress. In this study, globally dominant temperate and tropical forage grass species were grown in a greenhouse under current climate conditions and drought conditions that mimic future climate predictions to understand if (i) plant host taxa influence microbial community assembly, (ii) microbial communities respond to drought stress, and (iii) phyllosphere community changes correlate to changes in plant host traits and stress-response strategies. Community analysis using high resolution sequencing revealed Gammaproteobacteria as the dominant bacterial class, which increased under severe drought stress on both temperate and tropical grasses while overall bacterial community diversity declined. Bacterial community diversity, structure, and response to drought were significantly different between grass species. This community dependence on plant host species correlated with differences in grass species traits, which became more defined under drought stress conditions, suggesting symbiotic evolutionary relationships between plant hosts and their associated microbial community. Further understanding these strategies and the functions microbes provide to plants will help us utilize microbes to promote agricultural and ecosystem productivity in the future.

scholarly journals A MYB-related Transcription Factor from Sheepgrass, LcMYB2, Promotes Seed Germination and Root Growth under Drought Stress

2019 ◽  
Author(s):  
Pincang Zhao ◽  
Shenglin Hou ◽  
xiufang guo ◽  
Junting Jia ◽  
Weiguang Yang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Drought Stress ◽  
Seed Germination ◽  
Osmotic Stress ◽  
Root Growth ◽  
Genetic Manipulation ◽  
Marker Genes ◽  
Plant Responses ◽  
Adverse Conditions ◽  
Related Transcription Factor

Abstract Background Drought is one of the most serious factors limiting plant growth and production. Sheepgrass can adapt well to various adverse conditions, including drought. However, during germination, sheepgrass young seedlings are sensitive to these adverse conditions. Therefore, the adaptability of seedlings is very important for plant survival, especially in plants that inhabit grasslands or the construction of artificial grassland. Results In this study, we found a sheepgrass MYB-related transcription factor, LcMYB2 that is up-regulated by drought stress and returns to a basal level after rewatering. The expression of LcMYB2 was mainly induced by osmotic stress and was localized to the nucleus. Furthermore, we demonstrate that LcMYB2 promoted seed germination and root growth under drought and ABA treatments. Additionally, we confirmed that LcMYB2 can regulate LcDREB2 expression in sheepgrass by binding to its promoter, and it activates the expression of the osmotic stress marker genes AtDREB2A, AtLEA14 and AtP5CS1 by directly binding to their promoters in transgenic Arabidopsis. Conclusions Based on these results, we propose that LcMYB2 improves plant drought stress tolerance by increasing the accumulation of osmoprotectants and promoting root growth. Therefore, LcMYB2 plays pivotal roles in plant responses to drought stress and is an important candidate for genetic manipulation to create drought-resistant crops, especially during seed germination.

scholarly journals Evaluation of a Substrate-applied Humectant to Mitigate Drought Stress in Young, Container-grown Plants

2015 ◽  
Vol 33 (3) ◽  
pp. 137-141
Author(s):  
Bruce R. Roberts ◽  
Chris Wolverton ◽  
Samantha West
Keyword(s):  
Drought Stress ◽  
Root Growth ◽  
Shoot Growth ◽  
Dry Weight ◽  
Root:Shoot Ratio ◽  
Xylem Water Potential ◽  
Bedding Plants ◽  
Shoot Dry Weight ◽  
Soilless Substrate ◽  
Absorbing Roots

The efficacy of treating soilless substrate with a commercial humectant was tested as a means of suppressing drought stress in 4-week-old container-grown Zinnia elegans Jacq. ‘Thumbelina’. The humectant was applied as a substrate amendment at concentrations of 0.0, 0.8, 1.6 and 3.2% by volume prior to withholding irrigation. An untreated, well-watered control was also included. The substrate of treated plants was allowed to dry until the foliage wilted, at which time the plants were harvested and the following measurements taken: number of days to wilt (DTW), xylem water potential (ψx), shoot growth (shoot dry weight, leaf area) and root growth (length, diameter, surface area, volume, dry weight). For drought-stressed plants grown in humectant-treated substrate at concentrations of 1.6 and 3.2%, DTW increased 25 and 33%, respectively. A linear decrease in ψx was observed as the concentration of humectant increased from 0.0 to 3.2%. Linear trends were also noted for both volumetric moisture content (positive) and evapotranspiration (negative) as the concentration of humectant increased. For non-irrigated, untreated plants, stress inhibited shoot growth more than root growth, resulting in a lower root:shoot ratio. For non-irrigated, humectant-treated plants, the length of fine, water-absorbing roots increased linearly as humectant concentration increased from 0.0 to 3.2%. Using humectant-amended substrates may be a management option for mitigating the symptoms of drought stress during the production of container-grown bedding plants such as Z. elegans.

scholarly journals BrEXLB1, a Brassica rapa Expansin-Like B1 Gene Is Associated with Root Development, Drought Stress Response, and Seed Germination

Genes ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 404 ◽  
Author(s):  
Muthusamy Muthusamy ◽  
Joo Yeol Kim ◽  
Eun Kyung Yoon ◽  
Jin A. Kim ◽  
Soo In Lee
Keyword(s):  
Abiotic Stress ◽  
Drought Stress ◽  
Stress Response ◽  
Seed Germination ◽  
Drought Tolerance ◽  
Root Growth ◽  
Brassica Rapa ◽  
Root Development ◽  
Clubroot Disease ◽  
Qrt Pcr

Expansins are structural proteins prevalent in cell walls, participate in cell growth and stress responses by interacting with internal and external signals perceived by the genetic networks of plants. Herein, we investigated the Brassica rapa expansin-like B1 (BrEXLB1) interaction with phytohormones (IAA, ABA, Ethephon, CK, GA3, SA, and JA), genes (Bra001852, Bra001958, and Bra003006), biotic (Turnip mosaic Virus (TuMV), Pectobacterium carotovorum, clubroot disease), and abiotic stress (salt, oxidative, osmotic, and drought) conditions by either cDNA microarray or qRT-PCR assays. In addition, we also unraveled the potential role of BrEXLB1 in root growth, drought stress response, and seed germination in transgenic Arabidopsis and B. rapa lines. The qRT-PCR results displayed that BrEXLB1 expression was differentially influenced by hormones, and biotic and abiotic stress conditions; upregulated by IAA, ABA, SA, ethylene, drought, salt, osmotic, and oxidative conditions; and downregulated by clubroot disease, P. carotovorum, and TuMV infections. Among the tissues, prominent expression was observed in roots indicating the possible role in root growth. The root phenotyping followed by confocal imaging of root tips in Arabidopsis lines showed that BrEXLB1 overexpression increases the size of the root elongation zone and induce primary root growth. Conversely, it reduced the seed germination rate. Further analyses with transgenic B. rapa lines overexpressing BrEXLB1 sense (OX) and antisense transcripts (OX-AS) confirmed that BrEXLB1 overexpression is positively associated with drought tolerance and photosynthesis during vegetative growth phases of B. rapa plants. Moreover, the altered expression of BrEXLB1 in transgenic lines differentially influenced the expression of predicted BrEXLB1 interacting genes like Bra001852 and Bra003006. Collectively, this study revealed that BrEXLB1 is associated with root development, drought tolerance, photosynthesis, and seed germination.

Changes in drought resistance and root growth capacity of container seedlings in response to nursery drought, nitrogen, and potassium treatments

1992 ◽  
Vol 22 (5) ◽  
pp. 740-749 ◽  
Author(s):  
R. van den Driessche
Keyword(s):  
Drought Stress ◽  
Root Growth ◽  
Drought Resistance ◽  
Lodgepole Pine ◽  
Dry Weight ◽  
White Spruce ◽  
Douglas Fir ◽  
Growth Capacity ◽  
Root Growth Capacity ◽  
N Treatment

Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), lodgepole pine (Pinuscontorta Dougl.), and white spruce (Piceaglauca (Moench) Voss) seedlings, each represented by two seed lots, were grown in Styroblock containers in a greenhouse and plastic shelter house from February 1989 to January 1990. The seedlings were exposed to two nitrogen (N) treatments and three potassium (K) treatments arranged factorially within three drought treatments. After winter storage, seedlings from a complete set of treatments were planted into hygric, mesic, and xeric sand beds during 12–14 March. Increasing nursery drought stress increased survival of Douglas-fir and lodgepole pine after planting, and high N treatment level increased survival of lodgepole pine and white spruce. Under xeric conditions, combined nursery drought and high N treatments increased survival of lodgepole pine by 33%, indicating the importance of nursery cultural regime for stock quality. Increase in nursery drought decreased seedling size relatively little, but increase in N increased seedling size one season after planting. A positive relationship between shoot/root ratio and survival in lodgepole pine and white spruce indicated that increase in N increased both shoot growth and drought resistance over the N range investigated. Only Douglas-fir showed an interaction between drought and N treatment and a small response in both survival and dry weight to K. Root growth capacity, measured at the time of planting, showed an approximate doubling in all species due to high N treatment, and was also increased in white spruce by drought stress. Survival and root growth capacity were poorly correlated, but dry-weight growth in sand beds was well correlated with root growth capacity. Shoot dry weight and percent N in shoots measured after nursery growth were correlated with root growth capacity. Manipulation of root growth capacity by changing nursery treatment was apparently possible without altering resistance to drought stress after planting.

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