Multiple responses contribute to the enhanced drought tolerance of the autotetraploid Ziziphus jujuba Mill. var. spinosa

Abstract Background Polyploid plants often exhibit enhanced stress tolerance. The underlying physiological and molecular bases of such mechanisms remain elusive. Here, we characterized the drought tolerance of autotetraploid sour jujube at phenotypic, physiological and molecular levels. Results The study findings showed that the autotetraploid sour jujube exhibited a superior drought tolerance and enhanced regrowth potential after dehydration in comparison with the diploid counterpart. Under drought stress, more differentially expressed genes (DEGs) were detected in autotetraploid sour jujube and the physiological responses gradually triggered important functions. Through GO enrichment analysis, many DEGs between the diploid and autotetraploid sour jujube after drought-stress exposure were annotated to the oxidation–reduction process, photosystem, DNA binding transcription factor activity and oxidoreductase activity. Six reactive oxygen species scavenging-related genes were specifically differentially expressed and the larger positive fold-changes of the DEGs involved in glutathione metabolism were detected in autotetraploid. Consistently, the lower O2− level and malonaldehyde (MDA) content and higher antioxidant enzymes activity were detected in the autotetraploid under drought-stress conditions. In addition, DEGs in the autotetraploid after stress exposure were significantly enriched in anthocyanin biosynthesis, DNA replication, photosynthesis and plant hormone, including auxin, abscisic acid and gibberellin signal-transduction pathways. Under osmotic stress conditions, genes associated with the synthesis and transport of osmotic regulators including anthocyanin biosynthesis genes were differentially expressed, and the soluble sugar, soluble protein and proline contents were significantly higher in the autotetraploid. The higher chlorophyll content and DEGs enriched in photosynthesis suggest that the photosynthetic system in the autotetraploid was enhanced compared with diploid during drought stress. Moreover, several genes encoding transcription factors (TFs) including GRAS, Bhlh, MYB, WRKY and NAC were induced specifically or to higher levels in the autotetraploid under drought-stress conditions, and hub genes, LOC107403632, LOC107422279, LOC107434947, LOC107412673 and LOC107432609, related to 18 up-regulated transcription factors in the autotetraploid compared with the diploid were identified. Conclusion Taken together, multiple responses contribute to the enhanced drought tolerance of autotetraploid sour jujube. This study could provide an important basis for elucidating the mechanism of tolerance variation after the polyploidization of trees.

Download Full-text

Microbial Diversity of Upland Rice Roots and Their Influence on Rice Growth and Drought Tolerance

Microorganisms ◽

10.3390/microorganisms8091329 ◽

2020 ◽

Vol 8 (9) ◽

pp. 1329

Author(s):

Zhiqiang Pang ◽

Ying Zhao ◽

Peng Xu ◽

Diqiu Yu

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Plant Growth ◽

Upland Rice ◽

Oryza Sativa L ◽

Soluble Sugar ◽

Stress Conditions ◽

Rice Roots ◽

Microbial Resources

Among abiotic stresses, drought is one of the most important factors limiting plant growth. To increase their drought tolerance and survival, most plants interact directly with a variety of microbes. Upland rice (Oryza sativa L.) is a rice ecotype that differs from irrigated ecotype rice; it is adapted to both drought-stress and aerobic conditions. However, its root microbial resources have not been explored. We isolated bacteria and fungi from roots of upland rice in Xishuangbanna, China. Four hundred sixty-two endophytic and rhizospheric isolates (337 bacteria and 125 fungi) were distributed. They were distributed among 43 genera on the basis of 16S rRNA and internal transcribed spacer (ITS) gene sequence analysis. Notably, these root microbes differed from irrigated rice root microbes in irrigated environments; for example, members of the Firmicutes phylum were enriched (by 28.54%) in the roots of the upland plants. The plant growth-promoting (PGP) potential of 217 isolates was investigated in vitro. The PGP ability of 17 endophytic and 10 rhizospheric isolates from upland rice roots was evaluated under well-irrigated and drought-stress conditions, and 9 fungal strains increased rice seedling shoot length, shoot and root fresh weight (FW), antioxidant capability, and proline (Pro) and soluble sugar contents. Our work suggests that fungi from upland rice roots can increase plant growth under irrigated and drought-stress conditions and can serve as effective microbial resources for sustainable agricultural production in arid regions.

Download Full-text

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.

Download Full-text

Expression changes in the TaNAC2 and TaNAC69-1 transcription factors in drought stress tolerant and susceptible accessions of Triticum boeoticum

Plant Genetic Resources ◽

10.1017/s1479262119000303 ◽

2019 ◽

Vol 17 (6) ◽

pp. 471-479 ◽

Cited By ~ 3

Author(s):

Maryam Nazari ◽

Kiarash Jamshidi Goharrizi ◽

Sayyed Saeed Moosavi ◽

Mahmood Maleki

Keyword(s):

Transcription Factors ◽

Drought Stress ◽

Drought Tolerance ◽

Molecular Level ◽

Stress Conditions ◽

Wild Wheat ◽

Genes Expression ◽

Adaptive Mechanisms ◽

Triticum Boeoticum ◽

Modern Wheat

AbstractTriticum boeoticum is a valuable gene source for tolerance to drought stress. In order to study the effect of drought stress on this plant, and to understand its adaptive mechanisms at the molecular level, 10 accessions of T. boeoticum were evaluated under non- and drought stress conditions. Evaluation of 31 different phenological, morpho-physiological and root-related traits showed that there were significant differences between accessions. Using the bi-plot resulting from the PCA, the studied traits and accessions were separated in different groups. The most tolerant (B5) and susceptible (B6) accessions to drought stress were identified, so these accessions were used for assessment of changes in the TaNAC2 and TaNAC69-1 transcription factors (TFs) expression. The results showed that in the most tolerant and susceptible accessions, TaNAC2 and TaNAC69-1 expression levels increased between non-stress and stress conditions significantly, but the increased level of these two genes expression in the most tolerant accession was much higher than the most susceptible accession. According to the obtained results, T. boeoticum can be a suitable and promising gene source for improving modern wheat. In addition, the results of TFs expression could improve our understanding about the complex mechanisms associated with drought tolerance in wheat, especially wild wheat.

Download Full-text

De Novo Assembly and Discovery of Genes That Involved in Drought Tolerance in the Common Vetch

International Journal of Molecular Sciences ◽

10.3390/ijms20020328 ◽

2019 ◽

Vol 20 (2) ◽

pp. 328 ◽

Cited By ~ 4

Author(s):

Yongqun Zhu ◽

Qiuxu Liu ◽

Wenzhi Xu ◽

Jianhua Zhang ◽

Xie Wang ◽

...

Keyword(s):

Transcription Factors ◽

Drought Tolerance ◽

Molecular Mechanisms ◽

De Novo ◽

Reduction Process ◽

Differentially Expressed ◽

Forage Production ◽

Common Vetch ◽

Oxidoreductase Activity ◽

The Common

The common vetch (Vicia sativa) is often used as feed for livestock because of its high nutritional value. However, drought stress reduces forage production through plant damage. Here, we studied the transcriptional profiles of common vetch exposed to drought in order to understand the molecular mechanisms of drought tolerance in this species. The genome of the common vetch has not been sequenced, therefore we used Illumina sequencing to generate de novo transcriptomes. Nearly 500 million clean reads were used to generate 174,636 transcripts, including 122,299 unigenes. In addition, 5313 transcription factors were identified and these transcription factors were classified into 79 different gene families. We also identified 11,181 SSR loci from di- to hexa-nucleotides whose repeat number was greater than five. On the basis of differentially expressed genes, Gene Ontology analysis identified many drought-relevant categories, including “oxidation-reduction process”, “lipid metabolic process” and “oxidoreductase activity”. In addition to these, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified pathways, such as “Plant hormone signal transduction”, “Glycolysis/Gluconeogenesis” and “Phenylpropanoid biosynthesis”, as differentially expressed in the plants exposed to drought. The expression results in this study will be useful for further extending our knowledge on the drought tolerance of common vetch.

Download Full-text

Comparing transcriptional responses to Fusarium crown rot in wheat and barley identified an important relationship between disease resistance and drought tolerance

BMC Plant Biology ◽

10.1186/s12870-020-02818-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Z. Y. Su ◽

J. J. Powell ◽

S. Gao ◽

M. Zhou ◽

C. Liu

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Crown Rot ◽

Differentially Expressed ◽

Transcriptional Responses ◽

Drought Treatment ◽

Crop Species ◽

Fusarium Crown Rot ◽

Important Relationship ◽

The Impact

Abstract Background Fusarium crown rot (FCR) is a chronic disease in cereal production worldwide. The impact of this disease is highly environmentally dependant and significant yield losses occur mainly in drought-affected crops. Results In the study reported here, we evaluated possible relationships between genes conferring FCR resistance and drought tolerance using two approaches. The first approach studied FCR induced differentially expressed genes (DEGs) targeting two barley and one wheat loci against a panel of genes curated from the literature based on known functions in drought tolerance. Of the 149 curated genes, 61.0% were responsive to FCR infection across the three loci. The second approach was a comparison of the global DEGs induced by FCR infection with the global transcriptomic responses under drought in wheat. This analysis found that approximately 48.0% of the DEGs detected one week following drought treatment and 74.4% of the DEGs detected three weeks following drought treatment were also differentially expressed between the susceptible and resistant isolines under FCR infection at one or more timepoints. As for the results from the first approach, the vast majority of common DEGs were downregulated under drought and expressed more highly in the resistant isoline than the sensitive isoline under FCR infection. Conclusions Results from this study suggest that the resistant isoline in wheat was experiencing less drought stress, which could contribute to the stronger defence response than the sensitive isoline. However, most of the genes induced by drought stress in barley were more highly expressed in the susceptible isolines than the resistant isolines under infection, indicating that genes conferring drought tolerance and FCR resistance may interact differently between these two crop species. Nevertheless, the strong relationship between FCR resistance and drought responsiveness provides further evidence indicating the possibility to enhance FCR resistance by manipulating genes conferring drought tolerance.

Download Full-text

Genetic Diversity of Selected Rice Genotypes under Water Stress Conditions

Plants ◽

10.3390/plants10010027 ◽

2020 ◽

Vol 10 (1) ◽

pp. 27

Author(s):

Mahmoud M. Gaballah ◽

Azza M. Metwally ◽

Milan Skalicky ◽

Mohamed M. Hassan ◽

Marian Brestic ◽

...

Keyword(s):

Genetic Diversity ◽

Water Stress ◽

Drought Stress ◽

Drought Tolerance ◽

Ssr Markers ◽

Similarity Index ◽

Stress Conditions ◽

Yield Potential ◽

Drought Tolerant ◽

Rice Genotypes

Drought is the most challenging abiotic stress for rice production in the world. Thus, developing new rice genotype tolerance to water scarcity is one of the best strategies to achieve and maximize high yield potential with water savings. The study aims to characterize 16 rice genotypes for grain and agronomic parameters under normal and drought stress conditions, and genetic differentiation, by determining specific DNA markers related to drought tolerance using Simple Sequence Repeats (SSR) markers and grouping cultivars, establishing their genetic relationship for different traits. The experiment was conducted under irrigated (normal) and water stress conditions. Mean squares due to genotype × environment interactions were highly significant for major traits. For the number of panicles/plants, the genotypes Giza179, IET1444, Hybrid1, and Hybrid2 showed the maximum mean values. The required sterility percentage values were produced by genotypes IET1444, Giza178, Hybrid2, and Giza179, while, Sakha101, Giza179, Hybrid1, and Hybrid2 achieved the highest values of grain yield/plant. The genotypes Giza178, Giza179, Hybrid1, and Hybrid2, produced maximum values for water use efficiency. The effective number of alleles per locus ranged from 1.20 alleles to 3.0 alleles with an average of 1.28 alleles, and the He values for all SSR markers used varied from 0.94 to 1.00 with an average of 0.98. The polymorphic information content (PIC) values for the SSR were varied from 0.83 to 0.99, with an average of 0.95 along with a highly significant correlation between PIC values and the number of amplified alleles detected per locus. The highest similarity coefficient between Giza181 and Giza182 (Indica type) was observed and are susceptible to drought stress. High similarity percentage between the genotypes (japonica type; Sakha104 with Sakha102 and Sakha106 (0.45), Sakha101 with Sakha102 and Sakha106 (0.40), Sakha105 with Hybrid1 (0.40), Hybrid1 with Giza178 (0.40) and GZ1368-S-5-4 with Giza181 (0.40)) was also observed, which are also susceptible to drought stress. All genotypes are grouped into two major clusters in the dendrogram at 66% similarity based on Jaccard’s similarity index. The first cluster (A) was divided into two minor groups A1 and A2, in which A1 had two groups A1-1 and A1-2, containing drought-tolerant genotypes like IET1444, GZ1386-S-5-4 and Hybrid1. On the other hand, the A1-2 cluster divided into A1-2-1 containing Hybrid2 genotype and A1-2-2 containing Giza179 and Giza178 at coefficient 0.91, showing moderate tolerance to drought stress. The genotypes GZ1368-S-5-4, IET1444, Giza 178, and Giza179, could be included as appropriate materials for developing a drought-tolerant variety breeding program. Genetic diversity to grow new rice cultivars that combine drought tolerance with high grain yields is essential to maintaining food security.

Download Full-text

Identification of Two Novel Wheat Drought Tolerance-Related Proteins by Comparative Proteomic Analysis Combined with Virus-Induced Gene Silencing

International Journal of Molecular Sciences ◽

10.3390/ijms19124020 ◽

2018 ◽

Vol 19 (12) ◽

pp. 4020 ◽

Cited By ~ 8

Author(s):

Xinbo Wang ◽

Yanhua Xu ◽

Jingjing Li ◽

Yongzhe Ren ◽

Zhiqiang Wang ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Gene Silencing ◽

Proteomic Analysis ◽

Crop Yields ◽

Stress Conditions ◽

Virus Induced Gene Silencing ◽

Knock Down ◽

Comparative Proteomic Analysis ◽

Related Proteins

Drought is a major adversity that limits crop yields. Further exploration of wheat drought tolerance-related genes is critical for the genetic improvement of drought tolerance in this crop. Here, comparative proteomic analysis of two wheat varieties, XN979 and LA379, with contrasting drought tolerance was conducted to screen for drought tolerance-related proteins/genes. Virus-induced gene silencing (VIGS) technology was used to verify the functions of candidate proteins. A total of 335 differentially abundant proteins (DAPs) were exclusively identified in the drought-tolerant variety XN979. Most DAPs were mainly involved in photosynthesis, carbon fixation, glyoxylate and dicarboxylate metabolism, and several other pathways. Two DAPs (W5DYH0 and W5ERN8), dubbed TaDrSR1 and TaDrSR2, respectively, were selected for further functional analysis using VIGS. The relative electrolyte leakage rate and malonaldehyde content increased significantly, while the relative water content and proline content significantly decreased in the TaDrSR1- and TaDrSR2-knock-down plants compared to that in non-knocked-down plants under drought stress conditions. TaDrSR1- and TaDrSR2-knock-down plants exhibited more severe drooping and wilting phenotypes than non-knocked-down plants under drought stress conditions, suggesting that the former were more sensitive to drought stress. These results indicate that TaDrSR1 and TaDrSR2 potentially play vital roles in conferring drought tolerance in common wheat.

Download Full-text

Transcriptional Regulation of Hydrogen Peroxide and Calcium for Signaling Transduction and Stress-defensive Genes Contributing to Improved Drought Tolerance in Creeping Bentgrass

Journal of the American Society for Horticultural Science ◽

10.21273/jashs04901-19 ◽

2020 ◽

Vol 145 (4) ◽

pp. 236-246

Author(s):

Zhou Li ◽

Yan Peng ◽

Bingru Huang

Keyword(s):

Transcription Factors ◽

Drought Stress ◽

Drought Tolerance ◽

Creeping Bentgrass ◽

Grass Species ◽

Regulation Of Transcription ◽

Signaling Transduction ◽

Genes Expression ◽

Protective Genes ◽

Ca Signaling

Small molecules, including H2O2 and Ca, mediate stress signaling and drought tolerance in plants. The objective of this study was to determine whether improvement in drought tolerance by H2O2 and Ca were associated with the regulation of transcription factors and stress-protective genes in perennial grass species. Plants of creeping bentgrass (Agrostis stolonifera) were sprayed with water (control), H2O2 (9 mm), or CaCl2 (10 mm) and exposed to drought stress for 20 days in controlled-environment growth chambers. Foliar application of H2O2 or Ca led to significant improvement in drought tolerance of creeping bentgrass, as demonstrated by greater turf quality, leaf relative water content, chlorophyll content, photochemical efficiency, and cell membrane stability, as compared with the untreated control. The application of H2O2 and Ca resulted in significant up-regulation of genes in Ca signaling transduction pathways [Ca-dependent kinase 26 (CDPK26), mitogen-activated protein kinase 1 (MAPK1), and 14-3-3] and transcript factors (WRKY75 and MYB13). For genes encoding antioxidant enzymes, H2O2 mainly enhanced superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and dehydroascorbate reductase (DHAR) expression, while Ca primarily improved transcript levels of SOD, monodehydroascorbate reductase (MDHAR), and GR. In addition, heat shock protein 70 (HSP70), metallothionein 1 (MT1), and glutamine synthetase 2 (GS2) were also markedly up-regulated by H2O2 and Ca under drought stress. However, the transcript level of lipoxygenase 3 (LOX3) was significantly down-regulated by H2O2 and Ca under well-watered and drought conditions. These results imply that H2O2 and Ca commonly or differentially regulate genes expression in association with drought tolerance through activating Ca signaling pathway and regulating transcription factors and stress-protective genes expression, leading to the alleviation of lipid peroxidation, maintenance of correct protein folding and translocation, and enhancement of nitrogen metabolism under a prolonged period of drought stress in creeping bentgrass.

Download Full-text

The enhancement of drought tolerance for pigeon pea inoculated by arbuscular mycorrhizae fungi

Plant Soil and Environment ◽

10.17221/116/2011-pse ◽

2011 ◽

Vol 57 (No. 12) ◽

pp. 541-546 ◽

Cited By ~ 6

Author(s):

G. Qiao ◽

X.P. Wen ◽

L.F. Yu ◽

X.B. Ji

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Arbuscular Mycorrhizae ◽

Soluble Sugar ◽

Lipid Peroxides ◽

Am Fungi ◽

Pigeon Pea ◽

Positive Effects ◽

Am Symbiosis ◽

Osmotic Solute

  Pigeon pea (Cajanus cajan) has been rapidly grown in the drought-striken Karst regions of southwest China. Present research aimed to investigate the effects of arbuscular mycorrhizae (AM) on the drought tolerance of pigeon pea, as well as to elucidate the physiological responses of AM-colonized seedlings to the water deficit. As subjected to drought stress, AM symbiosis (AMD) highly led to the positive effects on root system, plant height and stem diameter. AMD demonstrated a remarkably higher chlorophyll content, photosynthetic rate and stomatal conductance. The soluble sugar in AMD was significantly higher than that of the non-AM seedlings (NAMD), indicating the enhanced tolerance at least partially correlated with osmotic solute. Conversely, the proline (Pro) of AMD was lower, revealing the excessive Pro was not imperative for drought tolerance. After 30 days drought stress, AMD gave around a third less lipid peroxides than that of NAMD. Rather, the root activities of AMD were significantly higher than that of the latter after 10 days drought stress. Thereby, AM fungi might substantially elevate the tolerance to drought of pigeon pea, and the cumulative effects contributed to the enhanced tolerance. To date, this has been the first report concerning the enhancement of drought tolerance via AM colonization in this legume species.  

Download Full-text

The interplay between miR156/SPL13 and DFR/WD40–1 regulate drought tolerance in alfalfa

BMC Plant Biology ◽

10.1186/s12870-019-2059-5 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 8

Author(s):

Biruk A. Feyissa ◽

Muhammad Arshad ◽

Margaret Y. Gruber ◽

Susanne E. Kohalmi ◽

Abdelali Hannoufa

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Anthocyanin Biosynthesis ◽

Physiological Responses ◽

Biological Functions ◽

Altered Expression ◽

Transcript Levels ◽

Squamosa Promoter Binding Protein ◽

Fine Tune

Abstract Background Developing Medicago sativa L. (alfalfa) cultivars tolerant to drought is critical for the crop’s sustainable production. miR156 regulates various plant biological functions by silencing SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) transcription factors. Results To understand the mechanism of miR156-modulated drought stress tolerance in alfalfa we used genotypes with altered expression levels of miR156, miR156-regulated SPL13, and DIHYDROFLAVONOL-4-REDUCTASE (DFR) regulating WD40–1. Previously we reported the involvement of miR156 in drought tolerance, but the mechanism and downstream genes involved in this process were not fully studied. Here we illustrate the interplay between miR156/SPL13 and WD40–1/DFR to regulate drought stress by coordinating gene expression with metabolite and physiological strategies. Low to moderate levels of miR156 overexpression suppressed SPL13 and increased WD40–1 to fine-tune DFR expression for enhanced anthocyanin biosynthesis. This, in combination with other accumulated stress mitigating metabolites and physiological responses, improved drought tolerance. We also demonstrated that SPL13 binds in vivo to the DFR promoter to regulate its expression. Conclusions Taken together, our results reveal that moderate relative miR156 transcript levels are sufficient to enhance drought resilience in alfalfa by silencing SPL13 and increasing WD40–1 expression, whereas higher miR156 overexpression results in drought susceptibility.

Download Full-text