The Medicago truncatula HKT family: Ion transport properties and regulation of expression upon abiotic stresses and symbiosis

SUMMARYSoil salinity is one of the most important abiotic stresses affecting plant growth. In legumes, symbiotic nitrogen fixation in nodules is affected by salt stress, and salinity tolerance is variable among species. Genes from the High affinity K+ Transporter (HKT) family are known to play crucial roles in salt stress tolerance in different plant species. In legumes these transporters are still very poorly characterized.. Here we study the HKT transporter family from the model legume Medicago trunacatula, which is moderately tolerant to salinity. The genome of this species comprises five HKT genes, hereafter named MtHKT1;1 to MtHKT1;5. Phylogenetic analysis indicated that the MtHKT polypeptides belong to HKT subfamily 1. Three members (MtHKT1;2, MtHKT1;4 and MtHKT1;5) of the Medicago truncatula family were cloned and expressed in Xenopus oocytes. Their electrophysiological properties revealed a permeability 10 times higher for Na+ than for K+ and varying rectification properties. Expression analyses of the three MtHKT genes under different biotic and abiotic conditions suggested that MtHKT1;5 is the main transporter from this family in the root, the three genes sharing a decrease of expression in drought and salt stress conditions in non inoculated plants as well as plants inoculated with rhizobia. In the shoot, the three MtHKT would be present at similar levels independently on the applied stresses. Based on biomass and ion content analysis, the nodule appeared as the most sensitive organ to the applied salt and drought stresses. The level of expression of the three MtHKT genes was strongly decreased by both stresses in the nodule.

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Evaluation of Indigenous Olive Biocontrol Rhizobacteria as Protectants against Drought and Salt Stress

Microorganisms ◽

10.3390/microorganisms9061209 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1209

Author(s):

Nuria Montes-Osuna ◽

Carmen Gómez-Lama Cabanás ◽

Antonio Valverde-Corredor ◽

Garikoitz Legarda ◽

Pilar Prieto ◽

...

Keyword(s):

Salt Stress ◽

Abiotic Stresses ◽

Biochemical Parameters ◽

Biocontrol Agent ◽

Negative Effects ◽

Experimental Conditions ◽

Acds Gene ◽

Drought And Salt Stress ◽

Physiological And Biochemical

Stress caused by drought and salinity may compromise growth and productivity of olive (Olea europaea L.) tree crops. Several studies have reported the use of beneficial rhizobacteria to alleviate symptoms produced by these stresses, which is attributed in some cases to the activity of 1-aminocyclopropane-1-carboxylic acid deaminase (ACD). A collection of beneficial olive rhizobacteria was in vitro screened for ACD activity. Pseudomonas sp. PICF6 displayed this phenotype and sequencing of its genome confirmed the presence of an acdS gene. In contrast, the well-known root endophyte and biocontrol agent Pseudomonas simiae PICF7 was defective in ACD activity, even though the presence of an ACD-coding gene was earlier predicted in its genome. In this study, an unidentified deaminase was confirmed instead. Greenhouse experiments with olive ‘Picual’ plants inoculated either with PICF6 or PICF7, or co-inoculated with both strains, and subjected to drought or salt stress were carried out. Several physiological and biochemical parameters increased in stressed plants (i.e., stomatal conductance and flavonoids content), regardless of whether or not they were previously bacterized. Results showed that neither PICF6 (ACD positive) nor PICF7 (ACD negative) lessened the negative effects caused by the abiotic stresses tested, at least under our experimental conditions.

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An expression database for roots of the model legume Medicago truncatula under salt stress

BMC Genomics ◽

10.1186/1471-2164-10-517 ◽

2009 ◽

Vol 10 (1) ◽

pp. 517 ◽

Cited By ~ 49

Author(s):

Daofeng Li ◽

Zhen Su ◽

Jiangli Dong ◽

Tao Wang

Keyword(s):

Salt Stress ◽

Medicago Truncatula ◽

Model Legume

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Genetic variability and identification of quantitative trait loci affecting plant growth and chlorophyll fluorescence parameters in the model legume Medicago truncatula under control and salt stress conditions

Functional Plant Biology ◽

10.1071/fp13370 ◽

2014 ◽

Vol 41 (9) ◽

pp. 983 ◽

Cited By ~ 7

Author(s):

Sarah Exbrayat ◽

Georges Bertoni ◽

Mohamad Reza Naghavie ◽

Ali Peyghambari ◽

Mounavar Badri ◽

...

Keyword(s):

Salt Stress ◽

Chlorophyll Fluorescence ◽

Quantitative Trait Loci ◽

Genetic Variability ◽

Plant Growth ◽

Medicago Truncatula ◽

Quantitative Trait ◽

Chlorophyll Fluorescence Parameters ◽

Model Legume ◽

Fluorescence Parameters

Salinity is one of the major stresses that limits crop production worldwide and affects most physiological activities in plants. In order to study the genetic control of salt stress in the model legume Medicago truncatula Gaertn., an experiment was undertaken to determine the genetic variability and to identify quantitative trait loci (QTLs) controlling several traits related to plant growth and physiology in a population of recombinant inbred lines. Shoot and root DW, relative water content, leaf area, chlorophyll content, chlorophyll fluorescence parameters, and Na+ and K+ in shoots and roots were measured. The experiment was carried out with three replications. ANOVA showed a large genetic variation and transgressive segregation for the traits studied, suggesting putative complex tolerance mechanisms. A total of 21 QTLs were detected under control conditions and 19 QTLs were identified under 100 mm salt stress conditions, with three QTLs being common to both situations. The percentage of total phenotypic variance explained by the QTLs ranged from 4.6% to 23.01%. Overlapping QTLs for different traits were also observed, which enables us to discriminate independent traits from linked ones. The results should be helpful information for further functional analysis of salt tolerance in M. truncatula.

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A Medicago truncatula EF-Hand Family Gene, MtCaMP1, Is Involved in Drought and Salt Stress Tolerance

PLoS ONE ◽

10.1371/journal.pone.0058952 ◽

2013 ◽

Vol 8 (4) ◽

pp. e58952 ◽

Cited By ~ 19

Author(s):

Tian-Zuo Wang ◽

Jin-Li Zhang ◽

Qiu-Ying Tian ◽

Min-Gui Zhao ◽

Wen-Hao Zhang

Keyword(s):

Salt Stress ◽

Stress Tolerance ◽

Medicago Truncatula ◽

Salt Stress Tolerance ◽

Ef Hand ◽

Drought And Salt Stress ◽

Family Gene

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The role of watermelon caffeic acid O-methyltransferase (ClCOMT1) in melatonin biosynthesis and abiotic stress tolerance

Horticulture Research ◽

10.1038/s41438-021-00645-5 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Jingjing Chang ◽

Yanliang Guo ◽

Jingyi Yan ◽

Zixing Zhang ◽

Li Yuan ◽

...

Keyword(s):

Salt Stress ◽

Caffeic Acid ◽

Abiotic Stresses ◽

Essential Role ◽

Citrullus Lanatus ◽

Abiotic Stress Tolerance ◽

Plant Tolerance ◽

Drought And Salt Stress ◽

Almost All

AbstractMelatonin is a pleiotropic signaling molecule that regulates plant growth and responses to various abiotic stresses. The last step of melatonin synthesis in plants can be catalyzed by caffeic acid O-methyltransferase (COMT), a multifunctional enzyme reported to have N-acetylserotonin O-methyltransferase (ASMT) activity; however, the ASMT activity of COMT has not yet been characterized in nonmodel plants such as watermelon (Citrullus lanatus). Here, a total of 16 putative O-methyltransferase (ClOMT) genes were identified in watermelon. Among them, ClOMT03 (Cla97C07G144540) was considered a potential COMT gene (renamed ClCOMT1) based on its high identities (60.00–74.93%) to known COMT genes involved in melatonin biosynthesis, expression in almost all tissues, and upregulation under abiotic stresses. The ClCOMT1 protein was localized in the cytoplasm. Overexpression of ClCOMT1 significantly increased melatonin contents, while ClCOMT1 knockout using the CRISPR/Cas-9 system decreased melatonin contents in watermelon calli. These results suggest that ClCOMT1 plays an essential role in melatonin biosynthesis in watermelon. In addition, ClCOMT1 expression in watermelon was upregulated by cold, drought, and salt stress, accompanied by increases in melatonin contents. Overexpression of ClCOMT1 enhanced transgenic Arabidopsis tolerance against such abiotic stresses, indicating that ClCOMT1 is a positive regulator of plant tolerance to abiotic stresses.

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Characterization and Expression of KT/HAK/KUP Transporter Family Genes in Willow under Potassium Deficiency, Drought, and Salt Stresses

BioMed Research International ◽

10.1155/2020/2690760 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12 ◽

Cited By ~ 3

Author(s):

Meixia Liang ◽

Yachao Gao ◽

Tingting Mao ◽

Xiaoyan Zhang ◽

Shaoying Zhang ◽

...

Keyword(s):

Salt Stress ◽

Molecular Mechanisms ◽

Functional Characterization ◽

Regulatory Elements ◽

Forest Trees ◽

Transporter Family ◽

Whole Plant ◽

Drought And Salt Stress ◽

Drought And Salt Stresses ◽

Plant Level

The K+ transporter/high-affinity K+/K+ uptake (KT/HAK/KUP) transporters dominate K+ uptake, transport, and allocation that play a pivotal role in mineral homeostasis and plant adaptation to adverse abiotic stresses. However, molecular mechanisms towards K+ nutrition in forest trees are extremely rare, especially in willow. In this study, we identified 22 KT/HAK/KUP transporter genes in purple osier willow (designated as SpuHAK1 to SpuHAK22) and examined their expression under K+ deficiency, drought, and salt stress conditions. Both transcriptomic and quantitative real-time PCR (qRT-PCR) analyses demonstrated that SpuHAKs were predominantly expressed in stems, and the expression levels of SpuHAK1, SpuHAK2, SpuHAK3, SpuHAK7, and SpuHAK8 were higher at the whole plant level, whereas SpuHAK9, SpuHAK11, SpuHAK20, and SpuHAK22 were hardly detected in tested tissues. In addition, both K+ deficiency and salt stress decreased the tissue K+ content, while drought increased the tissue K+ content in purple osier plant. Moreover, SpuHAK genes were differentially responsive to K+ deficiency, drought, and salt stresses in roots. K+ deficiency and salt stress mainly enhanced the expression level of responsive SpuHAK genes. Fifteen putative cis-acting regulatory elements, including the stress response, hormone response, circadian regulation, and nutrition and development, were identified in the promoter region of SpuHAK genes. Our findings provide a foundation for further functional characterization of KT/HAK/KUP transporters in forest trees and may be useful for breeding willow rootstocks that utilize potassium more efficiently.

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Overexpression of GhMPK3 from Cotton Enhances Cold, Drought, and Salt Stress in Arabidopsis

Agronomy ◽

10.3390/agronomy11061049 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1049

Author(s):

Salisu Bello Sadau ◽

Adeel Ahmad ◽

Sani Muhammad Tajo ◽

Sani Ibrahim ◽

Bello Babatunde Kazeem ◽

...

Keyword(s):

Salt Stress ◽

Abiotic Stress ◽

Stress Responses ◽

Abiotic Stresses ◽

Leaf Water ◽

Mitogen Activated Protein Kinase ◽

Leaf Water Content ◽

Ion Leakage ◽

Cotton Production ◽

Drought And Salt Stress

Cotton production is hampered by a variety of abiotic stresses that wreak havoc on the growth and development of plants, resulting in significant financial losses. According to reports, cotton production areas have declined around the world as a result of the ongoing stress. Therefore, plant breeding programs are concentrating on abiotic stress-tolerant cotton varieties. Mitogen-activated protein kinase (MAPK) cascades are involved in plant growth, stress responses, and the hormonal signaling pathway. In this research, three abiotic stresses (cold, drought, and salt) were analyzed on GhMPK3 transformed Arabidopsis plants. The transgenic plant’s gene expression and morphologic analysis were studied under cold, drought, and salt stress. Physiological parameters such as relative leaf water content, excised leaf water loss, chlorophyll content, and ion leakage showed that overexpressed plants possess more stable content under stress conditions compared with the WT plants. Furthermore, GhMPK3 overexpressed plants had greater antioxidant activities and weaker oxidant activities. Silencing GhMPK3 in cotton inhibited its tolerance to drought stress. Our research findings strongly suggest that GhMPK3 can be regarded as an essential gene for abiotic stress tolerance in cotton plants.

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Comprehensive identification and characterization of abiotic stress and hormone responsive glycosyl hydrolase family 1 genes in Medicago truncatula

10.21203/rs.3.rs-17102/v1 ◽

2020 ◽

Author(s):

Junfeng Yang ◽

Lin Ma ◽

Wenbo Jiang ◽

Yu Yao ◽

Yuhong Tang ◽

...

Keyword(s):

Abiotic Stress ◽

Medicago Truncatula ◽

Abiotic Stresses ◽

Regulatory Elements ◽

Glycoside Hydrolase Family ◽

Evolutionary Analysis ◽

Sequence Alignments ◽

Defense Compounds ◽

Model Legume ◽

Hydrolase Family

Abstract Background: β-glucosidases (BGLUs) hydrolyze the β-D-glycosidic bond with retention of anomeric configuration. BGLUs were associated with many aspects of plant physiological processes, in particular biotic and abiotic stresses through the activation of phytohormones and defense compounds. However, no comprehensive and systematic investigation on the stress- or hormone-responsive BGLU proteins had ever been reported in plant.Results: In this study, total 51 BGLU genes of the glycoside hydrolase family 1 were identified in one of the model legume plant Medicago truncatula genome, and they were classified into five distinct clusters. Sequence alignments revealed several conserved and characteristic motifs among these MtBGLU proteins. Analyses of their putative signal peptides and N-glycosylation site suggested that the majority of MtBGLU members have dual targeting to the vacuole/chloroplast. Many regulatory elements possibly related with phytohormones and/or abiotic stresses were identified in MtBGLU genes. Moreover, Microarray and qPCR analyses showed that these MtBGLU genes exhibited distinct expression patterns in various tissues, and in response to different abiotic stress and hormonal treatments. Notably, MtBGLU21, MtBGLU22, MtBGLU28, and MtBGLU30 in cluster I were dramatically activated by NaCl, PEG, IAA, ABA, SA and GA3 treatments.Conclusion: Collectively, our genome-wide characterization, evolutionary analysis, and expression pattern analysis of MtBGLU genes suggested that BGLU proteins play crucial roles in response to various abiotic stresses and hormonal cues in M. truncatula. This systematic analysis provided valuable information for the functional characterization and utilization of these MtBGLU genes in improving stress tolerance in M. truncatula and/or other plant species.

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Identification and Expression Profiling of Nonphosphorus Glycerolipid Synthase Genes in Response to Abiotic Stresses in Dendrobium catenatum

Plants ◽

10.3390/plants10061204 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1204

Author(s):

Xinqiao Zhan ◽

Yichun Qian ◽

Bizeng Mao

Keyword(s):

Salt Stress ◽

Drought Stress ◽

Expression Profiling ◽

Abiotic Stresses ◽

Membrane Lipids ◽

Chinese Herb ◽

Growth Stages ◽

Limited Information ◽

Gene Structures ◽

Functional Investigation

Dendrobium catenatum, a valuable Chinese herb, frequently experiences abiotic stresses, such as cold and drought, under natural conditions. Nonphosphorus glycerolipid synthase (NGLS) genes are closely linked to the homeostasis of membrane lipids under abiotic stress in plants. However, there is limited information on NGLS genes in D. catenatum. In this study, a total of eight DcaNGLS genes were identified from the D. catenatum genome; these included three monogalactosyldiacylglycerol synthase (DcaMGD1, 2, 3) genes, two digalactosyldiacylglycerol synthase (DcaDGD1, 2) genes, and three sulfoquinovosyldiacylglycerol synthase (DcaSQD1, 2.1, 2.2) genes. The gene structures and conserved motifs in the DcaNGLSs showed a high conservation during their evolution. Gene expression profiling showed that the DcaNGLSs were highly expressed in specific tissues and during rapid growth stages. Furthermore, most DcaNGLSs were strongly induced by freezing and post-freezing recovery. DcaMGD1 and DcaSQDs were greatly induced by salt stress in leaves, while DcaDGDs were primarily induced by salt stress in roots. Under drought stress, most DcaNGLSs were regulated by circadian rhythms, and DcaSQD2 was closely associated with drought recovery. Transcriptome analysis also revealed that MYB might be regulated by circadian rhythm and co-expressed with DcaNGLSs under drought stress. These results provide insight for the further functional investigation of NGLS and the regulation of nonphosphorus glycerolipid biosynthesis in Dendrobium.

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Jasmonates and Plant Salt Stress: Molecular Players, Physiological Effects, and Improving Tolerance by Using Genome-Associated Tools

International Journal of Molecular Sciences ◽

10.3390/ijms22063082 ◽

2021 ◽

Vol 22 (6) ◽

pp. 3082

Author(s):

Celia Delgado ◽

Freddy Mora-Poblete ◽

Sunny Ahmar ◽

Jen-Tsung Chen ◽

Carlos R. Figueroa

Keyword(s):

Salt Stress ◽

Abiotic Stresses ◽

Synergistic Effects ◽

Antioxidant Response ◽

Crop Productivity ◽

Point Of View ◽

Physiological Effects ◽

Crop Tolerance ◽

Molecular Components ◽

Ja Signaling

Soil salinity is one of the most limiting stresses for crop productivity and quality worldwide. In this sense, jasmonates (JAs) have emerged as phytohormones that play essential roles in mediating plant response to abiotic stresses, including salt stress. Here, we reviewed the mechanisms underlying the activation and response of the JA-biosynthesis and JA-signaling pathways under saline conditions in Arabidopsis and several crops. In this sense, molecular components of JA-signaling such as MYC2 transcription factor and JASMONATE ZIM-DOMAIN (JAZ) repressors are key players for the JA-associated response. Moreover, we review the antagonist and synergistic effects between JA and other hormones such as abscisic acid (ABA). From an applied point of view, several reports have shown that exogenous JA applications increase the antioxidant response in plants to alleviate salt stress. Finally, we discuss the latest advances in genomic techniques for the improvement of crop tolerance to salt stress with a focus on jasmonates.

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