Physiological, Biochemical and Transcriptomic Analysis of the Aerial Parts (Leaf-Blade and Petiole) of Asarum sieboldii Responding to Drought Stress

Asarum sieboldii Miq. is a leading economic crop and a traditional medicinal herb in China. Leaf-blade and petiole are the only aerial tissues of A. sieboldii during the vegetative growth, playing a vital role in the accumulation and transportation of biomass energy. They also act as critical indicators of drought in agricultural management, especially for crops having underground stems. During drought, variations in the morphology and gene expression of the leaves and petioles are used to control agricultural irrigation and production. Besides, such stress can also alter the differential gene expression in these tissues. However, little is known about the drought-tolerant character of the aerial parts of A. sieboldii. In this study, we examined the physiological, biochemical and transcriptomic responses to the drought stress in the leaf blades and petioles of A. sieboldii. The molecular mechanism, involving in drought stress response, was elucidated by constructing the cDNA libraries and performing transcriptomic sequencing. Under drought stress, a total of 2,912 and 2,887 unigenes were differentially expressed in the leaf blade and petiole, respectively. The detection of many transcription factors and functional genes demonstrated that multiple regulatory pathways were involved in drought tolerance. In response to drought, the leaf blade and petiole displayed a general physiological character, a higher SOD and POD activity, a higher MDA content and lower chlorophyll content. Three unigenes encoding POD were up-regulated, which can improve POD activity. Essential oil in petiole was extracted. The relative contents of methyleugenol and safrole in essential oil were increased from 0.01% to 0.05%, and 3.89% to 16.97%, respectively, while myristicin slightly reduced from 24.87% to 21.52%. Additionally, an IGS unigene, involved in eugenol biobiosynthesis, was found up-regulated under drought stress, which was predicated to be responsible for the accumulation of methyleugenol and safrole. Simple sequence repeats (SSRs) were characterized in of A. sieboldii, and a total of 5,466 SSRs were identified. Among them, mono-nucleotides were the most abundant repeat units, accounting for 44.09% followed by tri-, tetra-, penta and hexa-nucleotide repeats. Overall, the present work provides a valuable resource for the population genetics studies of A. sieboldii. Besides, it provides much genomic information for the functional dissection of the drought-resistance in A. sieboldii., which will be useful to understand the bio-regulatory mechanisms linked with drought-tolerance to enhance its yield.

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Transcriptome Analysis Revealed GhWOX4 Intercedes Myriad Regulatory Pathways to Modulate Drought Tolerance and Vascular Growth in Cotton

International Journal of Molecular Sciences ◽

10.3390/ijms22020898 ◽

2021 ◽

Vol 22 (2) ◽

pp. 898

Author(s):

Muhammad Sajjad ◽

Xi Wei ◽

Lisen Liu ◽

Fuguang Li ◽

Xiaoyang Ge

Keyword(s):

Transcription Factors ◽

Drought Stress ◽

Drought Tolerance ◽

Plant Growth ◽

Growth And Development ◽

Differentially Expressed ◽

Growth And Yield ◽

Regulatory Pathways ◽

Vascular Growth

Cotton is a paramount cash crop around the globe. Among all abiotic stresses, drought is a leading cause of cotton growth and yield loss. However, the molecular link between drought stress and vascular growth and development is relatively uncharted. Here, we validated a crucial role of GhWOX4, a transcription factor, modulating drought stress with that of vasculature growth in cotton. Knock-down of GhWOX4 decreased the stem width and severely compromised vascular growth and drought tolerance. Conversely, ectopic expression of GhWOX4 in Arabidopsis enhanced the tolerance to drought stress. Comparative RNAseq analysis revealed auxin responsive protein (AUX/IAA), abscisic acid (ABA), and ethylene were significantly induced. Additionally, MYC-bHLH, WRKY, MYB, homeodomain, and heat-shock transcription factors (HSF) were differentially expressed in control plants as compared to GhWOX4-silenced plants. The promotor zone of GhWOX4 was found congested with plant growth, light, and stress response related cis-elements. differentially expressed genes (DEGs) related to stress, water deprivation, and desiccation response were repressed in drought treated GhWOX4-virus-induced gene silencing (VIGS) plants as compared to control. Gene ontology (GO) functions related to cell proliferation, light response, fluid transport, and flavonoid biosynthesis were over-induced in TRV: 156-0 h/TRV: 156-1 h (control) in comparison to TRV: VIGS-0 h/TRV: VIGS-1 h (GhWOX4-silenced) plants. This study improves our context for elucidating the pivotal role of GhWOX4 transcription factors (TF), which mediates drought tolerance, plays a decisive role in plant growth and development, and is likely involved in different regulatory pathways in cotton.

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Effect of penconazole and drought stress on the essential oil composition and gene expression of Mentha pulegium L. (Lamiaceae) at flowering stage

Acta Physiologiae Plantarum ◽

10.1007/s11738-014-1492-1 ◽

2014 ◽

Vol 36 (5) ◽

pp. 1167-1175 ◽

Cited By ~ 14

Author(s):

Halimeh Hassanpour ◽

Ramazan Ali Khavari-Nejad ◽

Vahid Niknam ◽

Khadijeh Razavi ◽

Farzaneh Najafi

Keyword(s):

Gene Expression ◽

Drought Stress ◽

Essential Oil ◽

Essential Oil Composition ◽

Oil Composition ◽

Flowering Stage ◽

Mentha Pulegium

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Evaluation of drought resistance and transcriptome analysis for the identification of drought-responsive genes in Iris germanica

Scientific Reports ◽

10.1038/s41598-021-95633-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jingwei Zhang ◽

Dazhuang Huang ◽

Xiaojie Zhao ◽

Man Zhang

Keyword(s):

Gene Expression ◽

Drought Stress ◽

Drought Resistance ◽

Molecular Mechanisms ◽

Cdna Libraries ◽

Sequencing Analysis ◽

Peg 6000 ◽

Sequencing Platform ◽

Iris Germanica ◽

Drought Resistant

AbstractIris germanica, a species with very high ornamental value, exhibits the strongest drought resistance among the species in the genus Iris, but the molecular mechanism underlying its drought resistance has not been evaluated. To investigate the gene expression profile changes exhibited by high-drought-resistant I. germanica under drought stress, 10 cultivars with excellent characteristics were included in pot experiments under drought stress conditions, and the changes in the chlorophyll (Chl) content, plasma membrane relative permeability (RP), and superoxide dismutase (SOD), malondialdehyde (MDA), free proline (Pro), and soluble protein (SP) levels in leaves were compared among these cultivars. Based on their drought-resistance performance, the 10 cultivars were ordered as follows: ‘Little Dream’ > ‘Music Box’ > ‘X’Brassie’ > ‘Blood Stone’ > ‘Cherry Garden’ > ‘Memory of Harvest’ > ‘Immortality’ > ‘White and Gold’ > ‘Tantara’ > ‘Clarence’. Using the high-drought-resistant cultivar ‘Little Dream’ as the experimental material, cDNA libraries from leaves and rhizomes treated for 0, 6, 12, 24, and 48 h with 20% polyethylene glycol (PEG)-6000 to simulate a drought environment were sequenced using the Illumina sequencing platform. We obtained 1, 976, 033 transcripts and 743, 982 unigenes (mean length of 716 bp) through a hierarchical clustering analysis of the resulting transcriptome data. The unigenes were compared against the Nr, Nt, Pfam, KOG/COG, Swiss-Prot, KEGG, and gene ontology (GO) databases for functional annotation, and the gene expression levels in leaves and rhizomes were compared between the 20% PEG-6000 stress treated (6, 12, 24, and 48 h) and control (0 h) groups using DESeq2. 7849 and 24,127 differentially expressed genes (DEGs) were obtained from leaves and rhizomes, respectively. GO and KEGG enrichment analyses of the DEGs revealed significantly enriched KEGG pathways, including ribosome, photosynthesis, hormone signal transduction, starch and sucrose metabolism, synthesis of secondary metabolites, and related genes, such as heat shock proteins (HSPs), transcription factors (TFs), and active oxygen scavengers. In conclusion, we conducted the first transcriptome sequencing analysis of the I. germanica cultivar ‘Little Dream’ under drought stress and generated a large amount of genetic information. This study lays the foundation for further exploration of the molecular mechanisms underlying the responses of I. germanica to drought stress and provides valuable genetic resources for the breeding of drought-resistant plants.

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Physiological response and secondary metabolites of three lavender genotypes under water deficit

Scientific Reports ◽

10.1038/s41598-021-98750-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hossein Gorgini Shabankareh ◽

Sarah Khorasaninejad ◽

Hasan Soltanloo ◽

Vahid Shariati

Keyword(s):

Drought Stress ◽

Essential Oil ◽

Block Design ◽

Dry Weight ◽

Pca Analysis ◽

Lavandula Angustifolia ◽

Drought Effect ◽

Aerial Parts ◽

Irrigation Regimes

AbstractLavandula genus is a considerable medicinal plant in pharmaceutical and cosmetics industries. Considering increasing threat of drought in the world, it is important to identify genotypes which can tolerate drought. It is also important to characterize quantity and quality of essential oils, and tolerance indicators of these genotypes against drought stress. Therefore, an experiment was conducted in Gorgan University of Agricultural Sciences and Natural Resources, Iran, during 2017 and 2018, to investigate these factors. It was a factorial experiment based on randomized complete block design with two treatments, three genotypes (Lavandula angustifolia cv. Hidcote, Lavandula angustifolia cv. Munstead, and Lavandula stricta), and four levels of drought stress (irrigation regimes) (I1: 100–90% (control), I2: 80–70%, I3: 60–50% and I4: 30–40% of field capacity) which was done with three repetitions. Drought increased amount of proline in leaves, antioxidant activity, activity of catalase, peroxidase, ascorbate peroxidase, and superoxide enzymes, malondialdehyde content, total flavonoids, total phenol, total sugar and essential oil percentage. The PCA analysis of different irrigation regimes showed that in the first component, the best traits are antioxidant enzymes CAT, SOD, APX, while in the second component, only the trait Catalase is the best trait. The results of PCA analysis in lavender genotypes showed that L. stricta exhibits the most affected physiological changes while trying to adjust to changes in the water status of the environment, under the imposed conditions and shows the highest resistance. But it reduced dry weight of aerial parts, relative water content of leaves, and efficacy of essential oil. Lavandula stricta genotype had the highest amount of essential oil, but the highest dry weight of the aerial parts and essential oil yield were related to L. angustifolia cv. Hidcote and L. angustifolia cv. Munstead genotypes. In all evaluated genotypes, with increasing drought stress, monoterpene compounds were decreased and sesquiterpene compounds were increased. Totally it was shown that drought effect on evaluated traits depends on genotype and nature of traits; this indicates that by choosing drought-tolerant genotypes in breeding programs, high quantity and quality of essential oil, as well as tolerance to drought stress can be achieved.

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Revealing the Effects of Potassium on Rice Roots under Moisture Stress

10.24047/bc102428 ◽

2018 ◽

Vol 102 (4) ◽

pp. 28-31

Author(s):

Kirti Bardhan ◽

Dipika Patel ◽

Dhiraji Patel

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Root Architecture ◽

Plant Root ◽

Moisture Stress ◽

Rice Roots ◽

Aerial Parts ◽

Organ Level ◽

Plant Root System

The role of K in providing drought tolerance in the aerial parts of plants at the cellular, molecular, tissue, and organ level is well established compared to the plant root system. However, it is known that plants acquire soil water from deeper layers by modifying root architecture. The current study investigated the role of K in changing root architecture to facilitate more water acquisition as a mechanism to mitigate drought stress.

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Cellular Phosphorylation Signaling and Gene Expression in Drought Stress Responses: ABA-Dependent and ABA-Independent Regulatory Systems

Plants ◽

10.3390/plants10040756 ◽

2021 ◽

Vol 10 (4) ◽

pp. 756

Author(s):

Fumiyuki Soma ◽

Fuminori Takahashi ◽

Kazuko Yamaguchi-Shinozaki ◽

Kazuo Shinozaki

Keyword(s):

Gene Expression ◽

Transcription Factors ◽

Drought Stress ◽

Plant Growth ◽

Protein Kinases ◽

Stress Responses ◽

Regulatory Pathways ◽

Cis Acting ◽

Regulatory Systems ◽

Responsive Element

Drought is a severe and complex abiotic stress that negatively affects plant growth and crop yields. Numerous genes with various functions are induced in response to drought stress to acquire drought stress tolerance. The phytohormone abscisic acid (ABA) accumulates mainly in the leaves in response to drought stress and then activates subclass III SNF1-related protein kinases 2 (SnRK2s), which are key phosphoregulators of ABA signaling. ABA mediates a wide variety of gene expression processes through stress-responsive transcription factors, including ABA-RESPONSIVE ELEMENT BINDING PROTEINS (AREBs)/ABRE-BINDING FACTORS (ABFs) and several other transcription factors. Seed plants have another type of SnRK2s, ABA-unresponsive subclass I SnRK2s, that mediates the stability of gene expression through the mRNA decay pathway and plant growth under drought stress in an ABA-independent manner. Recent research has elucidated the upstream regulators of SnRK2s, RAF-like protein kinases, involved in early responses to drought stress. ABA-independent transcriptional regulatory systems and ABA-responsive regulation function in drought-responsive gene expression. DEHYDRATION RESPONSIVE ELEMENT (DRE) is an important cis-acting element in ABA-independent transcription, whereas ABA-RESPONSIVE ELEMENT (ABRE) cis-acting element functions in ABA-responsive transcription. In this review article, we summarize recent advances in research on cellular and molecular drought stress responses and focus on phosphorylation signaling and transcription networks in Arabidopsis and crops. We also highlight gene networks of transcriptional regulation through two major regulatory pathways, ABA-dependent and ABA-independent pathways, that ABA-responsive subclass III SnRK2s and ABA-unresponsive subclass I SnRK2s mediate, respectively. We also discuss crosstalk in these regulatory systems under drought stress.

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Early Drought-Responsive Genes Are Variable and Relevant to Drought Tolerance

G3 Genes|Genome|Genetics ◽

10.1534/g3.120.401199 ◽

2020 ◽

Vol 10 (5) ◽

pp. 1657-1670

Author(s):

Cheng He ◽

Yicong Du ◽

Junjie Fu ◽

Erliang Zeng ◽

Sunghun Park ◽

...

Keyword(s):

Gene Expression ◽

Drought Stress ◽

Drought Tolerance ◽

Small Rnas ◽

Gene Expression Regulation ◽

Limiting Factor ◽

Transcriptomic Data ◽

Number Variation ◽

Three Stages

Drought stress is an important crop yield limiting factor worldwide. Plant physiological responses to drought stress are driven by changes in gene expression. While drought-responsive genes (DRGs) have been identified in maize, regulation patterns of gene expression during progressive water deficits remain to be elucidated. In this study, we generated time-series transcriptomic data from the maize inbred line B73 under well-watered and drought conditions. Comparisons between the two conditions identified 8,626 DRGs and the stages (early, middle, and late drought) at which DRGs occurred. Different functional groups of genes were regulated at the three stages. Specifically, early and middle DRGs display higher copy number variation among diverse Zea mays lines, and they exhibited stronger associations with drought tolerance as compared to late DRGs. In addition, correlation of expression between small RNAs (sRNAs) and DRGs from the same samples identified 201 negatively sRNA/DRG correlated pairs, including genes showing high levels of association with drought tolerance, such as two glutamine synthetase genes, gln2 and gln6. The characterization of dynamic gene responses to progressive drought stresses indicates important adaptive roles of early and middle DRGs, as well as roles played by sRNAs in gene expression regulation upon drought stress.

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Transcriptome Analysis of Drought-Resistant and Drought-Sensitive Sorghum (Sorghum bicolor) Genotypes in Response to PEG-Induced Drought Stress

International Journal of Molecular Sciences ◽

10.3390/ijms21030772 ◽

2020 ◽

Vol 21 (3) ◽

pp. 772 ◽

Cited By ~ 5

Author(s):

Salah E. Abdel-Ghany ◽

Fahad Ullah ◽

Asa Ben-Hur ◽

Anireddy S. N. Reddy

Keyword(s):

Gene Expression ◽

Drought Stress ◽

Drought Tolerance ◽

Transcriptome Analysis ◽

Crop Yields ◽

Seedling Stage ◽

Limiting Factor ◽

Drought Resistant ◽

Sorghum Genotypes ◽

Resistant Genotypes

Drought is a major limiting factor of crop yields. In response to drought, plants reprogram their gene expression, which ultimately regulates a multitude of biochemical and physiological processes. The timing of this reprogramming and the nature of the drought-regulated genes in different genotypes are thought to confer differential tolerance to drought stress. Sorghum is a highly drought-tolerant crop and has been increasingly used as a model cereal to identify genes that confer tolerance. Also, there is considerable natural variation in resistance to drought in different sorghum genotypes. Here, we evaluated drought resistance in four genotypes to polyethylene glycol (PEG)-induced drought stress at the seedling stage and performed transcriptome analysis in seedlings of sorghum genotypes that are either drought-resistant or drought-sensitive to identify drought-regulated changes in gene expression that are unique to drought-resistant genotypes of sorghum. Our analysis revealed that about 180 genes are differentially regulated in response to drought stress only in drought-resistant genotypes and most of these (over 70%) are up-regulated in response to drought. Among these, about 70 genes are novel with no known function and the remaining are transcription factors, signaling and stress-related proteins implicated in drought tolerance in other crops. This study revealed a set of drought-regulated genes, including many genes encoding uncharacterized proteins that are associated with drought tolerance at the seedling stage.

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Antioxidative Responses and Candidate Gene Expression in Prairie Junegrass under Drought Stress

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.135.4.303 ◽

2010 ◽

Vol 135 (4) ◽

pp. 303-309 ◽

Cited By ~ 17

Author(s):

Yiwei Jiang ◽

Eric Watkins ◽

Shuwei Liu ◽

Xiaoqing Yu ◽

Na Luo

Keyword(s):

Gene Expression ◽

Drought Stress ◽

Drought Tolerance ◽

Candidate Gene ◽

Antioxidative Responses ◽

Relative Water ◽

Antioxidative Enzyme Activities ◽

Koeleria Macrantha ◽

Leaf Relative Water Content ◽

Copper Zinc

Prairie junegrass (Koeleria macrantha) is a native cool-season C3 grass that has shown potential as a low-input turfgrass. An increased understanding of the physiological and molecular responses of prairie junegrass to water-deficit conditions is important for developing cultivars with enhanced drought tolerance. The objective of this study was to characterize the antioxidative responses and candidate gene expression in prairie junegrass subjected to drought stress. Two drought-tolerant (TOL-1 and TOL-2) and two drought-susceptible (SUS-1 and SUS-2) genotypes of prairie junegrass were subjected to 7 days of drought stress. Leaf relative water content (RWC) of SUS-1 and SUS-2 was 72.1% and 73.8% and RWC of TOL-1 and TOL-2 was 90.1% and 85.4% in drought-stressed plants, respectively. Drought stress did not affect chlorophyll fluorescence, lipid peroxidation, and antioxidative enzyme activities of superoxide dismutase (SOD), catalase (CAT), peroxidase, ascorbate peroxidase (APX), or glutathione reductase for tolerant or susceptible genotypes. The TOL-2 and SUS-2 genotypes were further examined for candidate gene expression. Drought stress did not alter expression levels of CAT and chloroplastic copper/zinc SOD (Cu/ZnSOD), but increased levels of APX in either genotype, compared with their relative controls. Expression of P5CS encoding Δ1-pyrroline-5-carboxylate synthetase and P5CR encoding Δ1-pyrroline-5-carboxylate reductase for proline biosynthesis were up-regulated under drought stress for both genotypes; however, expression of P5CR was more strongly induced under drought stress for TOL-2, compared with its control. The expression of 1-FFT encoding fructan:fructan 1-fructosyltransferase, which is involved in fructan biosynthesis, was strongly induced under drought stress for TOL-2 but not detected under either control or drought stress conditions for SUS-2. These results indicate that the genes involved in proline and fructan biosynthesis may play an important role in drought tolerance in prairie junegrass.

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Phytohormones Trigger Drought Tolerance in Crop Plants: Outlook and Future Perspectives

Frontiers in Plant Science ◽

10.3389/fpls.2021.799318 ◽

2022 ◽

Vol 12 ◽

Author(s):

Shehzad Iqbal ◽

Xiukang Wang ◽

Iqra Mubeen ◽

Muhammad Kamran ◽

Iqra Kanwal ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Drought Resistance ◽

Signal Transduction Pathway ◽

Feedback Mechanism ◽

Vital Role ◽

Crop Plants ◽

Osmotic Balance ◽

Physical Stature

In the past and present, human activities have been involved in triggering global warming, causing drought stresses that affect animals and plants. Plants are more defenseless against drought stress; and therefore, plant development and productive output are decreased. To decrease the effect of drought stress on plants, it is crucial to establish a plant feedback mechanism of resistance to drought. The drought reflex mechanisms include the physical stature physiology and biochemical, cellular, and molecular-based processes. Briefly, improving the root system, leaf structure, osmotic-balance, comparative water contents and stomatal adjustment are considered as most prominent features against drought resistance in crop plants. In addition, the signal transduction pathway and reactive clearance of oxygen are crucial mechanisms for coping with drought stress via calcium and phytohormones such as abscisic acid, salicylic acid, jasmonic acid, auxin, gibberellin, ethylene, brassinosteroids and peptide molecules. Furthermore, microorganisms, such as fungal and bacterial organisms, play a vital role in increasing resistance against drought stress in plants. The number of characteristic loci, transgenic methods and the application of exogenous substances [nitric oxide, (C28H48O6) 24-epibrassinolide, proline, and glycine betaine] are also equally important for enhancing the drought resistance of plants. In a nutshell, the current review will mainly focus on the role of phytohormones and related mechanisms involved in drought tolerance in various crop plants.

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