Project description:<p>Combined saline-alkali and cold stresses severely constrain plant growth at middle and high latitudes. Plants have evolved cross-adaptation mechanisms wherein exposure to one stress enhances resistance to another. However, the specific mechanisms driving cross-adaptation between saline-alkali and cold stresses in alfalfa (Medicago sativa L.) remain to be elucidated. Here, we performed integrated transcriptomic and metabolomic analyses coupled with functional validation to elucidate these mechanisms. We found that saline-alkali pretreatment significantly enhanced the tolerance of alfalfa to subsequent cold stress. Compared to cold stress alone, cross-stress conditions increased osmolyte content and photosynthetic efficiency, while alleviating cellular oxidative damage. Integrated omics analyses revealed that cross-stress specifically activated flavonoid biosynthesis, carbohydrate metabolism and abscisic acid (ABA) biosynthesis and signaling pathways. This promoted the accumulation of endogenous ABA, flavonoids, and carbohydrates. Weighted gene co-expression network analysis identified MsNCED3 as a critical hub gene. Exogenous ABA improved photoprotection and sugar accumulation, and enhanced cold tolerance. MsNCED3 overexpression in alfalfa validated its pivotal role in cross-adaptation by elevating ABA levels and mitigating oxidative damage. In conclusion, we found that MsNCED3-mediated ABA accumulation, along with enhanced antioxidant and osmotic adjustment capabilities, serve as key mechanisms underlying the cross-adaptation of alfalfa to saline-alkali and cold stresses.</p>
2026-03-22 | MTBLS14108 | MetaboLights
Project description:Metabolo-transcriptomics analyses reveal alfalfa adaptation to combined saline-alkali and low-temperature stress in the field
Project description:Abstract: In order to understand the expression patterns of miRNAs in alfalfa under alkali stress, small RNA sequencing was performed on alfalfa roots at different time points under alkali stress, and miRNAs were identified and analyzed.
Project description:Abstract: In order to clarify the response mechanism of alfalfa under alkali stress, the transcriptome of roots was sequenced at different time points after stress and the expression patterns of all genes were analyzed.
2023-05-08 | GSE231696 | GEO
Project description:Multi-omics analysis revealed the response mechanism of alfalfa to combined cold and saline-alkali stress
Project description:Salt stress, especially saline-alkali stress, has seriously negative effect on citrus production. Ziyang xiangcheng (Citrus junos Sieb.) (Cj) has been reported as a saline-alkali stress and iron deficiency tolerant citrus rootstock. However, the molecular mechanism of its saline-alkali stress tolerance is still not clear. Two citrus rootstocks and one navel orange scion, Cj, Poncirus trifoliate (Poncirus trifoliata (L.) Raf.) (Pt) and ‘Lane Late’ navel orange (Citrus sinensis (L.) Osb.) (LL), were used in this study. The grafted materials Cj+LL and Pt+LL grown in calcareous soil were used to identify genes and pathways responsive to saline-alkali stress using RNA-seq. The seedlings of Cj and Pt grown in the solutions with different gradient pH value were used to perform a supplement experiment. Comprehensively analyzing the data of RNA-seq, physiology and biochemistry, agronomic traits and mineral elements of Cj+LL, Pt+LL, Cj and Pt, several candidate pathways and genes were identified to be highly regulated under saline-alkali stress. Here, we propose citrate is important for the tolerance to iron deficiency and the jasmonate (JA) biosynthesis and signal transduction pathway may play a crucial role in tolerance to saline-alkali stress in citrus by interacting with other plant hormones, calcium signaling, ROS scavenging system and lignin biosynthesis.
Project description:With the growing limitations on arable land, alfalfa (a widely cultivated, low-input forage) is now being selected to extend cultivation into saline lands for low-cost biofeedstock purposes. Here, minerals and transcriptome profiles were compared between two new salinity-tolerant North American alfalfa breeding populations and a more salinity-sensitive Western Canadian alfalfa population grown under hydroponic saline conditions. All three populations accumulated two-fold higher sodium in roots than shoots as a function of increased electrical conductivity. At least 50% of differentially expressed genes (p < 0.05) were down-regulated in the salt-sensitive population growing under high salinity, while remaining unchanged in the saline-tolerant populations. In particular, most reduction in transcript levels in the salt-sensitive population were observed in genes specifying cell wall structural components, lipids, secondary metabolism, auxin and ethylene hormones, development, transport, signalling, heat shock, proteolysis, pathogenesis-response, abiotic stress, RNA processing, and protein metabolism. Transcript diversity for transcription factors, protein modification, and protein degradation genes was also more strongly affected in salt-tolerant CW064027 than in salt-tolerant Bridgeview and salt-sensitive Rangelander, while both saline-tolerant populations showed more substantial up-regulation in redox-related genes and B-ZIP transcripts. The report highlights the first use of bulked genotypes as replicated samples to compare the transcriptomes of obligate out-cross breeding populations in alfalfa.
Project description:Soil salination and alkalization are global problems impairing plant survival by disrupting REDOX homeostasis. Whether melatonin regulates REDOX homeostasis at nitrosative level, and thus affects plant saline-alkali tolerance remains unknown. In saline-alkali stress, excess nitric oxide (NO) causes nitrosative damage in tomato roots. This NO can be degraded by S-nitrosoglutathione reductase (GSNOR), or stimulates caffeic acid O-methyltransferase (COMT) transcript for melatonin synthesis. Melatonin further feedback scavenges excess NO to alleviate nitrosative damage at the whole protein level, indicating by proteome S-nitrosylation. We target plasma membrane H+-ATPase 2 (HA2) and highlight that HA2 is S-nitrosylated at Cys206 in saline-alkali stress, reducing HA activity, H+ efflux, and tolerance by impairing its interaction with 14-3-3 protein 1 (TFT1). In agreement with these observations, COMT-mediated melatonin relieves the HA2 S-nitrosylation to recover its function and saline-alkali tolerance. Therefore, we propose NO and melatonin as a pair of REDOX switches to control HA2 S-nitrosylation and saline-alkali tolerance. Under natural saline-alkali conditions, tomato productivity can be improved by grafting with COMT-, GSNOR-, HA2-overexpression rootstocks or by genetic engineering non-nitrosylated HA2C206S mutants. Using melatonin-NO-HA2 module as a case, this study illuminates a novel molecular function of melatonin and relevant genetic engineering strategies in future agriculture.
Project description:Alkaline salts (e.g., NaHCO3 and Na2CO3) causes more severe morphological and physiological damage to plants than neutral salts (e.g., NaCl and Na2SO4) due to differences in pH. The mechanism by which plants respond to alkali stress is not fully understood, especially in plants having symbotic relationships such as alfalfa (Medicago sativa L.). Therefore, a study was designed to evaluate the metabolic response of the root-nodule symbiosis in alfalfa under alkali stress using comparative metabolomics. Rhizobium-nodulized (RI group) and non-nodulized (NI group) alfalfa roots were treated with 200 mmol/L NaHCO3 and, roots samples were analyzed for malondialdehydyde (MDA), proline, glutathione (GSH), superoxide dismutase (SOD), and peroxidase (POD) content. Additionally, metabolite profiling was conducted using gas chromatography combined with time-of-flight mass spectrometry (GC/TOF-MS). Phenotypically, the RI alfalfa exhibited a greater resistance to alkali stress than the NI plants examined. Physiological analysis and metabolic profiling revealed that RI plants accumulated more antioxidants (SOD, POD, GSH), osmolytes (sugar, glycols, proline), organic acids (succinic acid, fumaric acid, and alpha-ketoglutaric acid), and metabolites that are involved in nitrogen fixation. Our pairwise metabolomics comparisons revealed that RI alfalfa plants exhibited a distinct metabolic profile associated with alkali putative tolerance relative to NI alfalfa plants. Data provide new information about the relationship between non-nodulized, rhizobium-nodulized alfalfa and alkali resistance.
Project description:With the growing limitations on arable land, alfalfa (a widely cultivated, low-input forage) is now being selected to extend cultivation into saline lands for low-cost biofeedstock purposes. Here, minerals and transcriptome profiles were compared between two new salinity-tolerant North American alfalfa breeding populations and a more salinity-sensitive Western Canadian alfalfa population grown under hydroponic saline conditions. All three populations accumulated two-fold higher sodium in roots than shoots as a function of increased electrical conductivity. At least 50% of differentially expressed genes (p < 0.05) were down-regulated in the salt-sensitive population growing under high salinity, while remaining unchanged in the saline-tolerant populations. In particular, most reduction in transcript levels in the salt-sensitive population were observed in genes specifying cell wall structural components, lipids, secondary metabolism, auxin and ethylene hormones, development, transport, signalling, heat shock, proteolysis, pathogenesis-response, abiotic stress, RNA processing, and protein metabolism. Transcript diversity for transcription factors, protein modification, and protein degradation genes was also more strongly affected in salt-tolerant CW064027 than in salt-tolerant Bridgeview and salt-sensitive Rangelander, while both saline-tolerant populations showed more substantial up-regulation in redox-related genes and B-ZIP transcripts. The report highlights the first use of bulked genotypes as replicated samples to compare the transcriptomes of obligate out-cross breeding populations in alfalfa. Three lines of Alfalfa (salt-tolerant CW064027, salt-tolerant Bridgeview, salt-sensitive Rangelander) were grown on 3 different concentrations of salt. For each cultivar-salt condition, 3 biological replicates were collected for a total of 27 samples.