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1.
BMC Plant Biol ; 24(1): 954, 2024 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-39394556

RESUMEN

BACKGROUND: Drought stress is a major limiting factor that affects forage yields, and understanding the drought resistance mechanism of plants is crucial for improving crop yields in arid areas. Alfalfa (Medicago sativa L.) is the most important legume plant, mainly planted in arid and semi-arid areas. However, the adaptability of alfalfa to drought stress and its physiological and molecular mechanisms of drought resistance remains unclear. RESULTS: In this study, we analyzed the physiological and transcriptome responses of alfalfa cultivars with different drought resistances (drought-sensitive Gannong No. 3 (G3), drought-resistant Gannong No. 8 (G8), and strong drought-resistant Longdong (LD)) under drought stress at 0, 6, 12, and 24 h. LD had higher catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities and a higher soluble protein content, lower malondialdehyde (MDA) content, a lower O2·- production rate, and a lower H2O2 content than G8 and G3 (P < 0.05). The functional enrichment analysis, temporal expression pattern analysis, and weighted gene co-expression network analysis (WGCNA) of the differentially expressed genes (DEGs) showed phenylpropanoid biosynthesis, flavonoid biosynthesis, starch and sucrose metabolism, glycolysis/gluconeogenesis, glutathione metabolism, and biosynthesis of amino acid responses to drought stress in alfalfa. The differential expression of genes during phenylpropanoid biosynthesis, starch and sucrose metabolism, and the glutathione metabolism pathway was further studied, and it was speculated that PAL, COMT, 4CL, CCR, CAD, HXK, INV, SUS, WAXY, AGP, GST, and APX1 played important roles in the alfalfa drought stress response. CONCLUSIONS: The aim of this study was to enhance alfalfa drought resistance by overexpressing positively regulated genes and knocking out negatively regulated genes, providing genetic resources for the subsequent molecular-assisted breeding of drought-resistant alfalfa crops.


Asunto(s)
Sequías , Medicago sativa , Transcriptoma , Medicago sativa/genética , Medicago sativa/fisiología , Regulación de la Expresión Génica de las Plantas , Perfilación de la Expresión Génica , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Resistencia a la Sequía
2.
BMC Plant Biol ; 24(1): 898, 2024 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-39343877

RESUMEN

BACKGROUND: Medicago sativa, often referred to as the "king of forage", is prized for its high content of protein, minerals, carbohydrates, and digestible nutrients. However, various abiotic stresses can hinder its growth and development, ultimately resulting in reduced yield and quality, including water deficiency, high salinity, and low temperature. The ethylene-insensitive 3 (EIN3)/ethylene-insensitive 3-like (EIL) transcription factors are key regulators in the ethylene signaling pathway in plants, playing crucial roles in development and in the response to abiotic stresses. Research on the EIN3/EIL gene family has been reported for several species, but minimal information is available for M. sativa. RESULTS: In this study, we identified 10 MsEIN3/EIL genes from the M. sativa genome (cv. Zhongmu No.1), which were classified into three clades based on phylogenetic analysis. The conserved structural domains of the MsEIN3/EIL genes include motifs 1, 2, 3, 4, and 9. Gene duplication analyses suggest that segmental duplication (SD) has played a significant role in the expansion of the MsEIN3/EIL gene family throughout evolution. Analysis of the cis-acting elements in the promoters of MsEIN3/EIL genes indicates their potential to respond to various hormones and environmental stresses. We conducted a further analysis of the tissue-specific expression of the MsEIN3/EIL genes and assessed the gene expression profiles of MsEIN3/EIL under various stresses using transcriptome data, including cold, drought, salt and abscisic acid treatments. The results showed that MsEIL1, MsEIL4, and MsEIL5 may act as positive regulatory factors involved in M. sativa's response to abiotic stress, providing important genetic resources for molecular design breeding. CONCLUSION: This study investigated MsEIN3/EIL genes in M. sativa and identified three candidate transcription factors involved in the regulation of abiotic stresses. These findings will offer valuable insights into uncovering the molecular mechanisms underlying various stress responses in M. sativa.


Asunto(s)
Medicago sativa , Filogenia , Proteínas de Plantas , Estrés Fisiológico , Factores de Transcripción , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Medicago sativa/genética , Medicago sativa/fisiología , Estrés Fisiológico/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas , Familia de Multigenes , Genoma de Planta
3.
Physiol Plant ; 176(5): e14476, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39262125

RESUMEN

Drought stress is a predominant abiotic factor leading to decreased alfalfa yield. Genomic ploidy differences contribute to varying adaptation mechanisms of different alfalfa cultivars to drought conditions. This study employed a multi-omics approach to characterize the molecular basis of drought tolerance in a tetraploid variant of alfalfa (Medicago sativa, Xinjiang-Daye). Under drought treatment, a total of 4446 genes, 859 proteins, and 524 metabolites showed significant differences in abundance. Integrative analysis of the multi-omics data revealed that regulatory modules involved in flavonoid biosynthesis, plant hormone signalling transduction, linoleic acid metabolism, and amino acid biosynthesis play crucial roles in alfalfa adaptation to drought stress. The severity of drought led to the substantial accumulation of flavonoids, plant hormones, free fatty acids, amino acids, and their derivatives in the leaves. Genes such as PAL, 4CL, CHI, CHS, PP2C, ARF_3, and AHP_4 play pivotal regulatory roles in flavonoid biosynthesis and hormone signalling pathways. Differential expression of the LOX gene emerged as a key factor in the elevated levels of free fatty acids. Upregulation of P5CS_1 and GOT1/2 contributed significantly to the accumulation of Pro and Phe contents. ERF19 emerged as a principal positive regulator governing the synthesis of the aforementioned compounds. Furthermore, observations suggest that Xinjiang-Daye alfalfa may exhibit widespread post-transcriptional regulatory mechanisms in adapting to drought stress. The study findings unveil the critical mechanisms by which Xinjiang-Daye alfalfa adapts to drought stress, offering novel insights for the improvement of alfalfa germplasm resources.


Asunto(s)
Adaptación Fisiológica , Sequías , Regulación de la Expresión Génica de las Plantas , Medicago sativa , Tetraploidía , Medicago sativa/genética , Medicago sativa/fisiología , Medicago sativa/metabolismo , Adaptación Fisiológica/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estrés Fisiológico/genética , Flavonoides/metabolismo , Flavonoides/biosíntesis , Reguladores del Crecimiento de las Plantas/metabolismo , Multiómica
4.
Physiol Plant ; 176(4): e14446, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39092508

RESUMEN

Drought has a devastating impact, presenting a formidable challenge to agricultural productivity and global food security. Among the numerous ABC transporter proteins found in plants, the ABCG transporters play a crucial role in plant responses to abiotic stress. In Medicago sativa, the function of ABCG transporters remains elusive. Here, we report that MsABCG1, a WBC-type transporter highly conserved in legumes, is critical for the response to drought in alfalfa. MsABCG1 is localized on the plasma membrane, with the highest expression observed in roots under normal conditions, and its expression is induced by drought, NaCl and ABA signalling. In transgenic tobacco, overexpression of MsABCG1 enhanced drought tolerance, evidenced by increased osmotic regulatory substances and reduced lipid peroxidation. Additionally, drought stress resulted in reduced ABA accumulation in tobacco overexpressing MsABCG1, demonstrating that overexpression of MsABCG1 enhanced drought tolerance was not via an ABA-dependent pathway. Furthermore, transgenic tobacco exhibited increased stomatal density and reduced stomatal aperture under drought stress, indicating that MsABCG1 has the potential to participate in stomatal regulation during drought stress. In summary, these findings suggest that MsABCG1 significantly enhances drought tolerance in plants and provides a foundation for developing efficient drought-resistance strategies in crops.


Asunto(s)
Resistencia a la Sequía , Medicago sativa , Nicotiana , Proteínas de Plantas , Plantas Modificadas Genéticamente , Ácido Abscísico/metabolismo , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Resistencia a la Sequía/genética , Resistencia a la Sequía/fisiología , Regulación de la Expresión Génica de las Plantas , Medicago sativa/genética , Medicago sativa/fisiología , Medicago sativa/metabolismo , Nicotiana/genética , Nicotiana/fisiología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estomas de Plantas/fisiología , Estomas de Plantas/genética , Estrés Fisiológico/genética
5.
J Plant Physiol ; 302: 154319, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39106734

RESUMEN

Alfalfa often suffers from low temperature during spring rejuvenation, so it is important to improve the cold tolerance of alfalfa leaves for its smooth rejuvenation, and the alternative pathway (AP) could effectively improve the plant's tolerance. In this study, the contribution of AP on spring rejuvenation of alfalfa was investigated in Xinmu No.4 and Gannong No.5 with different fall dormancy levels. Though the protein and AP capacity were decreased during the rejuvenation, the ratio of AP/TP were increased in two alfalfa varieties, compared to those in alfalfa before overwintering. This indicated that AP had positive response to alfalfa rejuvenation. The limitation of AP significantly affected the leaf length, leaf width and growth rate of greening alfalfa, showing that AP played an important role in alfalfa rejuvenation. Inhibition of AP resulted in a significant decrease in Pn, Ci, Gs and stomatal structure deformity, suggestion that AP affected photosynthesis by influencing stomatal development during rejuvenation. AP reduces oxidative damage to PSII core protein repair in alfalfa leaves and optimizes photosynthesis by up-regulating NADP-MDH activity, decreasing the accumulation of excess reducing power in the chloroplasts, and by increasing SOD and POD activities and decreasing the accumulation of hydrogen peroxide. The higher proportion of AP keeps it more tolerant to low temperature for rejuvenation in Xinmu No.4 with a lower fall dormancy level.


Asunto(s)
Medicago sativa , Medicago sativa/fisiología , Medicago sativa/crecimiento & desarrollo , Medicago sativa/metabolismo , Hojas de la Planta/fisiología , Hojas de la Planta/crecimiento & desarrollo , Estaciones del Año , Fotosíntesis/fisiología , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Frío
6.
BMC Plant Biol ; 24(1): 800, 2024 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-39179986

RESUMEN

BACKGROUND: The mitogen-activated protein kinase (MAPK) cascade is crucial cell signal transduction mechanism that plays an important role in plant growth and development, metabolism, and stress responses. The MAPK cascade includes three protein kinases, MAPK, MAPKK, and MAPKKK. The three protein kinases mediate signaling to downstream response molecules by sequential phosphorylation. The MAPK gene family has been identified and analyzed in many plants, however it has not been investigated in alfalfa. RESULTS: In this study, Medicago sativa MAPK genes (referred to as MsMAPKs) were identified in the tetraploid alfalfa genome. Eighty MsMAPKs were divided into four groups, with eight in group A, 21 in group B, 21 in group C and 30 in group D. Analysis of the basic structures of the MsMAPKs revealed presence of a conserved TXY motif. Groups A, B and C contained a TEY motif, while group D contained a TDY motif. RNA-seq analysis revealed tissue-specificity of two MsMAPKs and tissue-wide expression of 35 MsMAPKs. Further analysis identified MsMAPK members responsive to drought, salt, and cold stress conditions. Two MsMAPKs (MsMAPK70 and MsMAPK75) responds to salt and cold stresses; two MsMAPKs (MsMAPK60 and MsMAPK73) responds to cold and drought stresses; four MsMAPKs (MsMAPK1, MsMAPK33, MsMAPK64 and MsMAPK71) responds to salt and drought stresses; and two MsMAPKs (MsMAPK5 and MsMAPK7) responded to all three stresses. CONCLUSION: This study comprehensively identified and analysed the alfalfa MAPK gene family. Candidate genes related to abiotic stresses were screened by analysing the RNA-seq data. The results provide key information for further analysis of alfalfa MAPK gene functions and improvement of stress tolerance.


Asunto(s)
Medicago sativa , Proteínas Quinasas Activadas por Mitógenos , Estrés Fisiológico , Medicago sativa/genética , Medicago sativa/enzimología , Medicago sativa/fisiología , Proteínas Quinasas Activadas por Mitógenos/genética , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Estrés Fisiológico/genética , Familia de Multigenes , Regulación de la Expresión Génica de las Plantas , Genoma de Planta , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Filogenia , Sequías
7.
BMC Plant Biol ; 24(1): 741, 2024 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-39095692

RESUMEN

BACKGROUND: Daye No.3 is a novel cultivar of alfalfa (Medicago sativa L.) that is well suited for cultivation in high-altitude regions such as the Qinghai‒Tibet Plateau owing to its high yield and notable cold resistance. However, the limited availability of transcriptomic information has hindered our investigation into the potential mechanisms of cold tolerance in this cultivar. Consequently, we conducted de novo transcriptome assembly to overcome this limitation. Subsequently, we compared the patterns of gene expression in Daye No. 3 during cold acclimatization and exposure to cold stress at various time points. RESULTS: A total of 15 alfalfa samples were included in the transcriptome assembly, resulting in 141.97 Gb of clean bases. A total of 441 DEGs were induced by cold acclimation, while 4525, 5016, and 8056 DEGs were identified at 12 h, 24 h, and 36 h after prolonged cold stress at 4 °C, respectively. The consistency between the RT‒qPCR and transcriptome data confirmed the accuracy and reliability of the transcriptomic data. KEGG enrichment analysis revealed that many genes related to photosynthesis were enriched under cold stress. STEM analysis demonstrated that genes involved in nitrogen metabolism and the TCA cycle were consistently upregulated under cold stress, while genes associated with photosynthesis, particularly antenna protein genes, were downregulated. PPI network analysis revealed that ubiquitination-related ribosomal proteins act as hub genes in response to cold stress. Additionally, the plant hormone signaling pathway was activated under cold stress, suggesting its vital role in the cold stress response of alfalfa. CONCLUSIONS: Ubiquitination-related ribosomal proteins induced by cold acclimation play a crucial role in early cold signal transduction. As hub genes, these ubiquitination-related ribosomal proteins regulate a multitude of downstream genes in response to cold stress. The upregulation of genes related to nitrogen metabolism and the TCA cycle and the activation of the plant hormone signaling pathway contribute to the enhanced cold tolerance of alfalfa.


Asunto(s)
Respuesta al Choque por Frío , Perfilación de la Expresión Génica , Medicago sativa , Transcriptoma , Medicago sativa/genética , Medicago sativa/fisiología , Respuesta al Choque por Frío/genética , Regulación de la Expresión Génica de las Plantas , Aclimatación/genética , Frío , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
8.
BMC Plant Biol ; 24(1): 776, 2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-39143536

RESUMEN

High temperature stress is one of the most severe forms of abiotic stress in alfalfa. With the intensification of climate change, the frequency of high temperature stress will further increase in the future, which will bring challenges to the growth and development of alfalfa. Therefore, untargeted metabolomic and RNA-Seq profiling were implemented to unravel the possible alteration in alfalfa seedlings subjected to different temperature stress (25 ℃, 30 ℃, 35 ℃, 40 ℃) in this study. Results revealed that High temperature stress significantly altered some pivotal transcripts and metabolites. The number of differentially expressed genes (DEGs) markedly up and down-regulated was 1876 and 1524 in T30_vs_CK, 2, 815 and 2667 in T35_vs_CK, and 2115 and 2, 226 in T40_vs_CK, respectively. The number for significantly up-regulated and down-regulated differential metabolites was 173 and 73 in T30_vs_CK, 188 and 57 in T35_vs_CK, and 220 and 66 in T40_vs_CK, respectively. It is worth noting that metabolomics and transcriptomics co-analysis characterized enriched in plant hormone signal transduction (ko04705), glyoxylate and dicarboxylate metabolism (ko00630), from which some differentially expressed genes and differential metabolites participated. In particular, the content of hormone changed significantly under T40 stress, suggesting that maintaining normal hormone synthesis and metabolism may be an important way to improve the HTS tolerance of alfalfa. The qRT-PCR further showed that the expression pattern was similar to the expression abundance in the transcriptome. This study provides a practical and in-depth perspective from transcriptomics and metabolomics in investigating the effects conferred by temperature on plant growth and development, which provided the theoretical basis for breeding heat-resistant alfalfa.


Asunto(s)
Medicago sativa , Metabolómica , Transcriptoma , Medicago sativa/genética , Medicago sativa/metabolismo , Medicago sativa/fisiología , Perfilación de la Expresión Génica , Metaboloma , Regulación de la Expresión Génica de las Plantas , Calor , Estrés Fisiológico/genética , Plantones/genética , Plantones/metabolismo , Plantones/fisiología , Plantones/crecimiento & desarrollo , Respuesta al Choque Térmico/genética
9.
BMC Genomics ; 25(1): 806, 2024 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-39192174

RESUMEN

BACKGROUND: Drought stress restricts the growth, distribution and productivity of alfalfa (Medicago sativa L.). In order to study the response differences of alfalfa cultivars to drought stress, we previously carried out physiological and molecular comparative analysis on two alfalfa varieties with contrasting drought resistance (relatively drought-tolerant Longdong and drought-sensitive Algonquin). However, the differences in proteomic factors of the two varieties in response to drought stress still need to be further studied. Therefore, TMT-based quantitative proteomic analysis was performed using leaf tissues of the two alfalfa cultivars to identify and uncover differentially abundant proteins (DAPs). RESULTS: In total, 677 DAPs were identified in Algonquin and 277 in Longdong under drought stress. Subsequently, we conducted various bioinformatics analysis on these DAPs, including subcellular location, functional classification and biological pathway enrichment. The first two main COG functional categories of DAPs in both alfalfa varieties after drought stress were 'Translation, ribosomal structure and biogenesis' and 'Posttranslational modification, protein turnover, chaperones'. According to KEGG database, the DAPs of the two alfalfa cultivars after drought treatment were differentially enriched in different biological pathways. The DAPs from Algonquin were enriched in 'photosynthesis' and 'ribosome'. The pathways of 'linoleic acid metabolism', 'protein processing in endoplasmic reticulum' and 'RNA transport' in Longdong were significantly enriched. Finally, we found significant differences in DAP enrichment and expression patterns between Longdong and Algonquin in glycolysis/glycogenesis, TCA cycle, photosynthesis, protein biosynthesis, flavonoid and isoflavonoid biosynthesis, and plant-pathogen interaction pathway after drought treatment. CONCLUSIONS: The differences of DAPs involved in various metabolic pathways may explain the differences in the resistance of the two varieties to drought stress. These DAPs can be used as candidate proteins for molecular breeding of alfalfa to cultivate new germplasm with more drought tolerance to adapt to unfavorable environments.


Asunto(s)
Sequías , Medicago sativa , Proteínas de Plantas , Proteómica , Estrés Fisiológico , Medicago sativa/genética , Medicago sativa/metabolismo , Medicago sativa/fisiología , Proteómica/métodos , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Espectrometría de Masas en Tándem , Proteoma/metabolismo , Biología Computacional/métodos , Regulación de la Expresión Génica de las Plantas , Hojas de la Planta/metabolismo
10.
BMC Plant Biol ; 24(1): 633, 2024 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-38971752

RESUMEN

BACKGROUND: Alfalfa (Medicago sativa L.) experiences many negative effects under salinity stress, which may be mediated by recurrent selection. Salt-tolerant alfalfa may display unique adaptations in association with rhizobium under salt stress. RESULTS: To elucidate inoculation effects on salt-tolerant alfalfa under salt stress, this study leveraged a salt-tolerant alfalfa population selected through two cycles of recurrent selection under high salt stress. After experiencing 120-day salt stress, mRNA was extracted from 8 random genotypes either grown in 0 or 8 dS/m salt stress with or without inoculation by Ensifer meliloti. Results showed 320 and 176 differentially expressed genes (DEGs) modulated in response to salinity stress or inoculation x salinity stress, respectively. Notable results in plants under 8 dS/m stress included upregulation of a key gene involved in the Target of Rapamycin (TOR) signaling pathway with a concomitant decrease in expression of the SNrK pathway. Inoculation of salt-stressed plants stimulated increased transcription of a sulfate-uptake gene as well as upregulation of the Lysine-27-trimethyltransferase (EZH2), Histone 3 (H3), and argonaute (AGO, a component of miRISC silencing complexes) genes related to epigenetic and post-transcriptional gene control. CONCLUSIONS: Salt-tolerant alfalfa may benefit from improved activity of TOR and decreased activity of SNrK1 in salt stress, while inoculation by rhizobiumstimulates production of sulfate uptake- and other unique genes.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Medicago sativa , Tolerancia a la Sal , Medicago sativa/genética , Medicago sativa/fisiología , Medicago sativa/microbiología , Tolerancia a la Sal/genética , Estrés Salino/genética , Salinidad , Sinorhizobium meliloti/fisiología , Plantas Tolerantes a la Sal/genética , Plantas Tolerantes a la Sal/fisiología
11.
Int J Mol Sci ; 25(13)2024 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-39000350

RESUMEN

Low temperature is the most common abiotic factor that usually occurs during the seed germination of alfalfa (Medicago sativa L.). However, the potential regulatory mechanisms involved in alfalfa seed germination under low temperature stress are still ambiguous. Therefore, to determine the relevant key genes and pathways, the phenotypic and transcriptomic analyses of low-temperature sensitive (Instict) and low-temperature tolerant (Sardi10) alfalfa were conducted at 6 and 15 h of seed germination under normal (20 °C) and low (10 °C) temperature conditions. Germination phenotypic results showed that Sardi10 had the strongest germination ability under low temperatures, which was manifested by the higher germination-related indicators. Further transcriptome analysis indicated that differentially expressed genes were mainly enriched in galactose metabolism and carbon metabolism pathways, which were the most commonly enriched in two alfalfa genotypes. Additionally, fatty acid metabolism and glutathione metabolism pathways were preferably enriched in Sardi10 alfalfa. The Weighted Gene Co-Expression Network Analysis (WGCNA) suggested that genes were closely related to galactose metabolism, fatty acid metabolism, and glutathione metabolism in Sardi10 alfalfa at the module with the highest correlation (6 h of germination under low temperature). Finally, qRT-PCR analysis further validated the related genes involved in the above pathways, which might play crucial roles in regulating seed germination of alfalfa under low temperature conditions. These findings provide new insights into the molecular mechanisms of seed germination underlying the low temperature stress in alfalfa.


Asunto(s)
Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Germinación , Medicago sativa , Fenotipo , Semillas , Transcriptoma , Medicago sativa/genética , Medicago sativa/fisiología , Medicago sativa/metabolismo , Germinación/genética , Semillas/genética , Semillas/crecimiento & desarrollo , Perfilación de la Expresión Génica/métodos , Frío , Respuesta al Choque por Frío/genética , Redes Reguladoras de Genes
12.
Physiol Plant ; 176(4): e14448, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39082126

RESUMEN

The ascorbate-glutathione pathway plays an essential role in the physiology of vascular plants, particularly in their response to environmental stresses. This pathway is responsible for regulating the cellular redox state, which is critical for maintaining cell function and survival under adverse conditions. To study the involvement of the alfalfa monodehydroascorbate reductase (MsMDHAR) in water stress processes, Arabidopsis thaliana plants constitutively expressing the sequence encoding MsMDHAR were developed. Transgenic events with low and high MsMDHAR expression and ascorbate levels were selected for further analysis of drought and waterlogging tolerance. Under water stress, Arabidopsis transgenic plants generated higher biomass, produced more seeds, and had larger roots than wild type ones. This higher tolerance was associated with increased production of waxes and chlorophyll a at the basal level, greater stomatal opening and stability in regulating the relative water content and reduced H2O2 accumulation under stress conditions in transgenic plants. Overall, these results show that MsMDHAR is involved in plant tolerance to abiotic stresses. The data presented here also emphasises the potential of the MsMDHAR enzyme as a plant breeding tool to improve water stress tolerance.


Asunto(s)
Arabidopsis , Regulación de la Expresión Génica de las Plantas , Medicago sativa , Plantas Modificadas Genéticamente , Arabidopsis/genética , Arabidopsis/fisiología , Medicago sativa/genética , Medicago sativa/fisiología , Sequías , NADH NADPH Oxidorreductasas/metabolismo , NADH NADPH Oxidorreductasas/genética , Agua/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estrés Fisiológico/genética , Peróxido de Hidrógeno/metabolismo , Deshidratación , Ácido Ascórbico/metabolismo , Estomas de Plantas/fisiología , Estomas de Plantas/genética
13.
Plant J ; 119(4): 1900-1919, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38943631

RESUMEN

Cold and saline-alkali stress are frequently encountered by plants, and they often occur simultaneously in saline-alkali soils at mid to high latitudes, constraining forage crop distribution and production. However, the mechanisms by which forage crops respond to the combination of cold and saline-alkali stress remain unknown. Alfalfa (Medicago sativa L.) is one of the most essential forage grasses in the world. In this study, we analyzed the complex response mechanisms of two alfalfa species (Zhaodong [ZD] and Blue Moon [BM]) to combined cold and saline-alkali stress using multi-omics. The results revealed that ZD had a greater ability to tolerate combined stress than BM. The tricarboxylic acid cycles of the two varieties responded positively to the combined stress, with ZD accumulating more sugars, amino acids, and jasmonic acid. The gene expression and flavonoid content of the flavonoid biosynthesis pathway were significantly different between the two varieties. Weighted gene co-expression network analysis and co-expression network analysis based on RNA-Seq data suggested that the MsMYB12 gene may respond to combined stress by regulating the flavonoid biosynthesis pathway. MsMYB12 can directly bind to the promoter of MsFLS13 and promote its expression. Moreover, MsFLS13 overexpression can enhance flavonol accumulation and antioxidant capacity, which can improve combined stress tolerance. These findings provide new insights into improving alfalfa resistance to combined cold and saline-alkali stress, showing that flavonoids are essential for plant resistance to combined stresses, and provide theoretical guidance for future breeding programs.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Medicago sativa , Metabolómica , Medicago sativa/genética , Medicago sativa/fisiología , Medicago sativa/metabolismo , Perfilación de la Expresión Génica , Estrés Fisiológico , Álcalis , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transcriptoma , Frío
14.
J Plant Physiol ; 297: 154262, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38703548

RESUMEN

Aluminum (Al) is the major limiting factor affecting plant productivity in acidic soils. Al3+ ions exhibit increased solubility at a pH below 5, leading to plant root tip toxicity. Alternatively, plants can perceive very low concentrations of Al3+, and Al triggers downstream signaling even at pH 5.7 without causing Al toxicity. The ALUMINUM-ACTIVATED-MALATE-TRANSPORTER (ALMT) family members act as anion channels, with some regulating the secretion of malate from root apices to chelate Al, which is a crucial mechanism for plant Al resistance. To date, the role of the ALMT gene family within the legume Medicago species has not been fully characterized. In this study, we investigated the ALMT gene family in M. sativa and M. truncatula and identified 68 MsALMTs and 18 MtALMTs, respectively. Phylogenetic analysis classified these genes into five clades, and synteny analysis uncovered genuine paralogs and orthologs. The real-time quantitative reverse transcription PCR (qRT-PCR) analysis revealed that MtALMT8, MtALMT9, and MtALMT15 in clade 2-2b are expressed in both roots and root nodules, and MtALMT8 and MtALMT9 are significantly upregulated by Al in root tips. We also observed that MtALMT8 and MtALMT9 can partially restore the Al sensitivity of Atalmt1 in Arabidopsis. Moreover, transcriptome analysis examined the expression patterns of these genes in M. sativa in response to Al at both pH 5.7 and pH 4.6, as well as to protons, and found that Al and protons can independently induce some Al-resistance genes. Overall, our findings indicate that MtALMT8 and MtALMT9 may play a role in Al resistance, and highlight the resemblance between the ALMT genes in Medicago species and those in Arabidopsis.


Asunto(s)
Aluminio , Perfilación de la Expresión Génica , Filogenia , Proteínas de Plantas , Aluminio/toxicidad , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Familia de Multigenes , Medicago truncatula/genética , Medicago truncatula/efectos de los fármacos , Medicago truncatula/metabolismo , Medicago sativa/genética , Medicago sativa/efectos de los fármacos , Medicago sativa/fisiología , Raíces de Plantas/genética , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Genoma de Planta , Transportadores de Anión Orgánico/genética , Transportadores de Anión Orgánico/metabolismo , Medicago/genética , Medicago/fisiología
15.
Mol Plant ; 17(6): 867-883, 2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38678365

RESUMEN

Given the escalating impact of climate change on agriculture and food security, gaining insights into the evolutionary dynamics of climatic adaptation and uncovering climate-adapted variation can empower the breeding of climate-resilient crops to face future climate change. Alfalfa (Medicago sativa subsp. sativa), the queen of forages, shows remarkable adaptability across diverse global environments, making it an excellent model for investigating species responses to climate change. In this study, we performed population genomic analyses using genome resequencing data from 702 accessions of 24 Medicago species to unravel alfalfa's climatic adaptation and genetic susceptibility to future climate change. We found that interspecific genetic exchange has contributed to the gene pool of alfalfa, particularly enriching defense and stress-response genes. Intersubspecific introgression between M. sativa subsp. falcata (subsp. falcata) and alfalfa not only aids alfalfa's climatic adaptation but also introduces genetic burden. A total of 1671 genes were associated with climatic adaptation, and 5.7% of them were introgressions from subsp. falcata. By integrating climate-associated variants and climate data, we identified populations that are vulnerable to future climate change, particularly in higher latitudes of the Northern Hemisphere. These findings serve as a clarion call for targeted conservation initiatives and breeding efforts. We also identified pre-adaptive populations that demonstrate heightened resilience to climate fluctuations, illuminating a pathway for future breeding strategies. Collectively, this study enhances our understanding about the local adaptation mechanisms of alfalfa and facilitates the breeding of climate-resilient alfalfa cultivars, contributing to effective agricultural strategies for facing future climate change.


Asunto(s)
Cambio Climático , Medicago sativa , Medicago sativa/genética , Medicago sativa/fisiología , Adaptación Fisiológica/genética , Genómica , Genoma de Planta
16.
BMC Plant Biol ; 24(1): 304, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38644487

RESUMEN

Biochar is a promising solution to alleviate the negative impacts of salinity stress on agricultural production. Biochar derived from food waste effect was investigated on three plant species, Medicago sativa, Amaranthus caudatus, and Zea mays, under saline environments. The results showed that biochar improved significantly the height by 30%, fresh weight of shoot by 35% and root by 45% of all three species compared to control (saline soil without biochar adding), as well as enhanced their photosynthetic pigments and enzyme activities in soil. This positive effect varied significantly between the 3 plants highlighting the importance of the plant-biochar interactions. Thus, the application of biochar is a promising solution to enhance the growth, root morphology, and physiological characteristics of plants under salt-induced stress.


Asunto(s)
Amaranthus , Carbón Orgánico , Medicago sativa , Suelo , Zea mays , Amaranthus/efectos de los fármacos , Amaranthus/crecimiento & desarrollo , Amaranthus/fisiología , Zea mays/crecimiento & desarrollo , Zea mays/efectos de los fármacos , Zea mays/fisiología , Medicago sativa/efectos de los fármacos , Medicago sativa/crecimiento & desarrollo , Medicago sativa/fisiología , Suelo/química , Salinidad , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/efectos de los fármacos , Fotosíntesis/efectos de los fármacos
17.
Plant Cell Environ ; 47(6): 2178-2191, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38481026

RESUMEN

Understanding crop responses to elevated CO2 is necessary to meet increasing agricultural demands. Crops may not achieve maximum potential yields at high CO2 due to photosynthetic downregulation, often associated with nitrogen limitation. Legumes have been proposed to have an advantage at elevated CO2 due to their ability to exchange carbon for nitrogen. Here, the effects of biological nitrogen fixation (BNF) on the physiological and gene expression responses to elevated CO2 were examined at multiple nitrogen levels by comparing alfalfa mutants incapable of nitrogen fixation to wild-type. Elemental analysis revealed a role for BNF in maintaining shoot carbon/nitrogen (C/N) balance under all nitrogen treatments at elevated CO2, whereas the effect of BNF on biomass was only observed at elevated CO2 and the lowest nitrogen dose. Lower photosynthetic rates at were associated with the imbalance in shoot C/N. Genome-wide transcriptional responses were used to identify carbon and nitrogen metabolism genes underlying the traits. Transcription factors important to C/N signalling were identified from inferred regulatory networks. This work supports the hypothesis that maintenance of C/N homoeostasis at elevated CO2 can be achieved in plants capable of BNF and revealed important regulators in the underlying networks including an alfalfa (Golden2-like) GLK ortholog.


Asunto(s)
Dióxido de Carbono , Carbono , Medicago sativa , Fijación del Nitrógeno , Nitrógeno , Fotosíntesis , Dióxido de Carbono/metabolismo , Nitrógeno/metabolismo , Carbono/metabolismo , Medicago sativa/genética , Medicago sativa/fisiología , Medicago sativa/metabolismo , Medicago sativa/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas , Brotes de la Planta/metabolismo , Brotes de la Planta/genética , Brotes de la Planta/fisiología
18.
BMC Plant Biol ; 23(1): 568, 2023 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-37968658

RESUMEN

BACKGROUND: Seed aging is a critical factor contributing to vigor loss, leading to delayed forage seed germination and seedling growth. Numerous studies have revealed the regulatory role of WRKY transcription factors in seed development, germination, and seed vigor. However, a comprehensive genome-wide analysis of WRKY genes in Zhongmu No.1 alfalfa has not yet been conducted. RESULTS: In this study, a total of 91 MsWRKY genes were identified from the genome of alfalfa. Phylogenetic analysis revealed that these MsWRKY genes could be categorized into seven distinct subgroups. Furthermore, 88 MsWRKY genes were unevenly mapped on eight chromosomes in alfalfa. Gene duplication analysis revealed segmental duplication as the principal driving force for the expansion of this gene family during the course of evolution. Expression analysis of the 91 MsWRKY genes across various tissues and during seed germination exhibited differential expression patterns. Subsequent RT-qPCR analysis highlighted significant induction of nine selected MsWRKY genes in response to seed aging treatment, suggesting their potential roles in regulating seed vigor. CONCLUSION: This study investigated WRKY genes in alfalfa and identified nine candidate WRKY transcription factors involved in the regulation of seed vigor. While this finding provides valuable insights into understanding the molecular mechanisms underlying vigor loss and developing new strategies to enhance alfalfa seed germinability, further research is required to comprehensively elucidate the precise pathways through which the MsWRKY genes modulate seed vigor.


Asunto(s)
Genómica , Medicago sativa , Medicago sativa/fisiología , Filogenia , Semillas/genética , Semillas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Regulación de la Expresión Génica de las Plantas
19.
Plant Mol Biol ; 110(6): 511-529, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35976552

RESUMEN

KEY MESSAGE: Our results show that SPL12 plays a crucial role in regulating nodule development in Medicago sativa L. (alfalfa), and that AGL6 is targeted and downregulated by SPL12. Root architecture in plants is critical because of its role in controlling nutrient cycling, water use efficiency and response to biotic and abiotic stress factors. The small RNA, microRNA156 (miR156), is highly conserved in plants, where it functions by silencing a group of SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) transcription factors. We previously showed that transgenic Medicago sativa (alfalfa) plants overexpressing miR156 display increased nodulation, improved nitrogen fixation and enhanced root regenerative capacity during vegetative propagation. In alfalfa, transcripts of eleven SPLs, including SPL12, are targeted for cleavage by miR156. In this study, we characterized the role of SPL12 in root architecture and nodulation by investigating the transcriptomic and phenotypic changes associated with altered transcript levels of SPL12, and by determining SPL12 regulatory targets using SPL12-silencing and -overexpressing alfalfa plants. Phenotypic analyses showed that silencing of SPL12 in alfalfa caused an increase in root regeneration, nodulation, and nitrogen fixation. In addition, AGL6 which encodes AGAMOUS-like MADS box transcription factor, was identified as being directly targeted for silencing by SPL12, based on Next Generation Sequencing-mediated transcriptome analysis and chromatin immunoprecipitation assays. Taken together, our results suggest that SPL12 and AGL6 form a genetic module that regulates root development and nodulation in alfalfa.


Asunto(s)
Medicago sativa , MicroARNs , Medicago sativa/fisiología , Regulación de la Expresión Génica de las Plantas , MicroARNs/genética , Transcriptoma , Perfilación de la Expresión Génica
20.
BMC Plant Biol ; 21(1): 446, 2021 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-34610811

RESUMEN

BACKGROUND: Alfalfa (Medicago sativa L.) production decreases under salt stress. Identification of genes associated with salt tolerance in alfalfa is essential for the development of molecular markers used for breeding and genetic improvement. RESULT: An RNA-Seq technique was applied to identify the differentially expressed genes (DEGs) associated with salt stress in two alfalfa cultivars: salt tolerant 'Halo' and salt intolerant 'Vernal'. Leaf and root tissues were sampled for RNA extraction at 0 h, 3 h, and 27 h under 12 dS m- 1 salt stress maintained by NaCl. The sequencing generated a total of 381 million clean sequence reads and 84.8% were mapped on to the alfalfa reference genome. A total of 237 DEGs were identified in leaves and 295 DEGs in roots of the two alfalfa cultivars. In leaf tissue, the two cultivars had a similar number of DEGs at 3 h and 27 h of salt stress, with 31 and 49 DEGs for 'Halo', 34 and 50 for 'Vernal', respectively. In root tissue, 'Halo' maintained 55 and 56 DEGs at 3 h and 27 h, respectively, while the number of DEGs decreased from 42 to 10 for 'Vernal'. This differential expression pattern highlights different genetic responses of the two cultivars to salt stress at different time points. Interestingly, 28 (leaf) and 31 (root) salt responsive candidate genes were highly expressed in 'Halo' compared to 'Vernal' under salt stress, of which 13 candidate genes were common for leaf and root tissues. About 60% of DEGs were assigned to known gene ontology (GO) categories. The genes were involved in transmembrane protein function, photosynthesis, carbohydrate metabolism, defense against oxidative damage, cell wall modification and protection against lipid peroxidation. Ion binding was found to be a key molecular activity for salt tolerance in alfalfa under salt stress. CONCLUSION: The identified DEGs are significant for understanding the genetic basis of salt tolerance in alfalfa. The generated genomic information is useful for molecular marker development for alfalfa genetic improvement for salt tolerance.


Asunto(s)
Medicago sativa/genética , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Estrés Salino/genética , Tolerancia a la Sal/genética , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Variación Genética , Genotipo , Medicago sativa/fisiología , Estrés Salino/fisiología , Tolerancia a la Sal/fisiología , Transcriptoma
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