TABLE 1.
Overview of proteins and metabolites important for biotechnological improvement of alfalfa as revealed by proteomic and metabolomic studies.
| Treatment, stress, condition | Sample | Methodological approach | Proteins and metabolites of biotechnological importance | References |
| Seed germination and osmopriming | Seeds | 2-D gel electrophoresis (nano-LC MS/MS) | Carbohydrate metabolism: UDP glucose pyrophosphorylase Protein destination and storage: HSP70 and HSP20, GroEL-like chaperone, ATPase, vicilin, protein disulfide-isomerase precursor Stress response: annexin, peroxiredoxins, manganese superoxide dismutase, glyoxalase, lipoxygenase, glutathione S-transferase, thioredoxin | Yacoubi et al. (2011) |
| Proteolysis: peptidase T1A, proteasome beta subunit, peptidase A1 pepsin | ||||
| Osmoprimed seeds germinating under salt stress | Seeds | 2-D gel electrophoresis (nano-LC MS/MS) | Small HSPs: 18.2 kDa class I HSP Methionine synthesis: methionine synthase, cysteine synthase Dehydration defense: LEA proteins, PM22 Others: annexin, RNA-binding protein, heme oxygenase, glutathione S-transferase 9 | Yacoubi et al. (2013) |
| PEG-induced osmotic stress | Roots of varieties contrasting in drought tolerance | iTRAQ (strong cation exchange fractionation and LC MS/MS) | Stress and defense: glutathione S-transferases, disease resistance response protein, epoxide hydrolase, chitinase, reticuline oxidase-like protein, low-temperature-induced 65 kDa protein, aldo/keto reductase, pirin-like plant protein, glucan endo-1,3-beta-glucosidase Protein metabolism: HSPs, lysine-ketoglutarate reductase/saccharopine dehydrogenase, phosphatidylethanolamine-binding protein, homoglutathione synthetase | Zhang and Shi (2018) |
| Signal transduction: monooxygenases, cysteine-rich RLK (receptor-like kinase) protein, 12-oxophytodienoate reductase | ||||
| Cell wall: beta xylosidase, xyloglucan-specific endoglucanase inhibitor protein, expansin-B1-like protein | ||||
| Salt stress | Roots of two cultivars contrasting in salt resistance | 2-D gel electrophoresis (MALDI TOF/TOF) | Oxidative stress: peroxidase, peroxiredoxin Protein folding: protein disulfide isomerase Metabolism: NAD synthetase, UTP-glucose 1 phosphate uridylyltransferase Fatty acid metabolism: biotin carboxylase 3 | Rahman et al. (2015) |
| Membrane transport: V-ATPase | ||||
| Salt and drought stress | Seedlings | 2-D gel electrophoresis (MALDI TOF-MS/MS) | Salt stress: caffeoyl-CoA 3-O-methyltransferase, peroxiredoxin, ubiquitin-conjugating enzyme, UV excision repair protein rad23, glutathione peroxidase | Ma et al. (2017) |
| Drought stress: ubiquitin-conjugating enzyme, putative alcohol dehydrogenase, chaperonin 10 | ||||
| Drought stress | Leaves of plants inoculated by S. meliloti | Proteomics: 2-D gel electrophoresis (LCMS/MS analysis) Metabolomics: GC TOF-MS | Rubisco availability and regeneration: rubisco activase, sedoheptulose-1,7-bisphosphatase, ribulose-phosphate 3-epimerase and phosphoribulokinase Nitrogen metabolism: glutamine synthetase | Aranjuelo et al. (2011) |
| Stress and defense response: superoxide dismutase, dehydroascorbate reductase, 2-cys peroxiredoxin-like protein, 14-3-3-like protein | ||||
| Osmoprotectant metabolites: proline, pinitol | ||||
| Drought stress | Nodules, roots, leaves | Proteomics: 2-D gel electrophoresis (LCMS/MS analysis) Metabolomics: GC TOF-MS | Nodule proteome: alpha 1,4-glucan protein synthase, lipoxygenase, PEP-carboxylase Nodule N containing metabolites: glutamine, asparagine Nodule osmoprotectant metabolites: glycerol, galactinol, myo-inositol, proline, sucrose, raffinose, fumaric acid and malate Nodule metabolites with antioxidant capacity: ascorbate, threonate | Aranjuelo et al. (2013) |
| Water deficit stress | Roots | 2-D gel electrophoresis (MALDI TOF) | Nitrogen metabolism: glutamine synthetase, ferredoxin-dependent glutamate synthase | Rahman et al. (2016) |
| ABA biosynthesis: 9-cis-epoxycarotenoid dioxygenase | ||||
| Stress response and oxidative stress: ascorbate peroxidase, peroxiredoxin, calreticulin, stress-induced phosphoprotein, annexin | ||||
| Transcription: basic helix-loop-helix (bHLH) transcription factor, agamous-like 65 Other functions: inward-rectifying potassium channel, auxin-independent growth promoter | ||||
| Heat stress | Leaves | 2-D gel electrophoresis (MALDI TOF/TOF) | Rubisco availability: Rubisco activase isoforms Nitrogen metabolism: aspartate aminotransferase and glutamine synthetase | Li W. et al. (2013) |
| Protein synthesis and processing: peptidyl-prolyl cis–trans isomerases, protein disulfide isomerase-like protein precursor, porin, proteasome subunit β type, eukaryotic translation initiation factor 3 subunit I, BiP isoform A/glycine max, cysteine proteinase, outer plastidial membrane protein porin | ||||
| Intracellular traffic, cell structure: protein TOC75, translocon Tic40, profilin | ||||
| Defense response: 17 kDa HSP, 18.2 kDa class I HSP, 20 kDa chaperonin, HSP23, HSP70, thaumatin-like protein, ubiquitin, ascorbate peroxidases, glucan endo-1,3-beta-glucosidase | ||||
| Cold acclimation | Leaves of cultivars tolerant or sensitive to freezing | 2-D gel electrophoresis (MALDI TOF/TOF) | Oxidative stress: monodehydroascorbate reductase, glutathione peroxidase, peptide methionine sulfoxide reductases A3, thioredoxin-like protein CDSP32, 2-cys peroxiredoxin BAS1-like | Chen et al. (2015) |
| Methionine biosynthesis: 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase | ||||
| Lignin and terpenoid biosynthesis: cinnamoyl-CoA reductase, 1-deoxy-D-xylulose 5-phosphate reductoisomerase | ||||
| Photosynthesis and Rubisco availability: Rubisco large subunit-binding protein subunit beta, Rubisco activase B, chlorophyll A/B binding protein, oxygen-evolving enhancer protein 1, cytochrome b6-f complex iron-sulfur subunit | ||||
| Protein folding and disassembling: chaperone protein ClpC, GTPase, peptidyl-prolyl cis–trans isomerase CYP20-3 | ||||
| Cadmium stress | Cell walls and soluble proteins from stems | 2-D DIGE (MALDI TOF/TOF) | Cell wall modification: sucrose synthase, pectinesterase/pectinesterase inhibitor, polygalacturonase non-catalytic protein, polygalacturonase-inhibiting protein 1, b-xylosidase/alpha-L-arabinofuranosidase, trichome birefringence-like protein, xyloglucan endotransglucosylase/hydrolase family protein, dirigent protein 21-like | Gutsch et al. (2018a) |
| Defense: chitinase (Class Ib)/hevein, chitinase, class I chitinase, disease resistance response protein, pathogenesis-related protein 1, pathogenesis-related thaumatin family protein, plant basic secretory protein (BSP) family protein, pre-hevein-like protein, stromal 70 kDa heat shock-related protein, CAP, cysteine-rich secretory protein, antigen 5 | ||||
| Oxidation-reduction process: anionic peroxidase swpb3 protein, class III peroxidase, peroxidase family protein, peroxidase1b, peroxidase2 | ||||
| Cadmium stress | Stems (soluble and cell wall enriched proteins) | 2-D DIGE (MALDI TOF/TOF) | Cell wall modification: pectinesterase/pectinesterase inhibitor, polygalacturonase non-catalytic protein, polygalacturonase-inhibiting protein 1 Chloroplast protein degradation: chloroplastic aspartyl protease isoforms Cell wall: class III peroxidase, lignin biosynthetic peroxidase, chitinases | Gutsch et al. (2018b) |
| Stem growth | Different regions of stems (apical, intermediate, and basal) | 2-D gel electrophoresis (MALDI TOF/TOF) | Chloroplast protein synthesis: CSP41-b, EF-Tu, EF-G, Cpn 60, HSP70 Lignin biosynthesis: transketolase, enolase Cytoplasmic protein synthesis: eIF-5a, endoplasmic protein disulfide isomerase, HSP90, ribosomal protein P3-like | Printz et al. (2015) |
| Vesicular trafficking: clathrin light chain | ||||
| Stress response: peroxisomal membrane protein, monodehydroascorbate reductase, flavoprotein wrbA-like, Pprg2 | ||||
| Sieve element development: sieve element occlusion by forisomes 3 | ||||
| Cadmium stress and hydrogen- rich water | Roots | iTRAQ (nano-LC MS/MS) | Defense response: mitogen-activated protein kinase, pathogenesis-related thaumatin family protein, pathogenesis-related protein bet V I family protein, disease-resistance response protein Nitrogen metabolism: glutamate dehydrogenase Sulfur compound metabolic process: cysteine synthase, ATP sulfurylase | Dai et al. (2017) |
| Secondary metabolism: chalcone-flavonone isomerase family protein | ||||
| Waterlogging | Leaves of two cultivars contrasting in tolerance to waterlogging | iTRAQ (reverse-phase HPLC fractionation and LC-MS/MS) | Cell wall and defense response: acidic endochitinase, expansin-like B1, early nodulin-like protein 2, thaumatin-like protein, 1,4 alpha-glucan-branching enzyme 1, pathogenesis-related protein Stress response: glutathione S-transferase, protein C2-DOMAIN ABA-RELATED 9, aldo-keto reductase family 4 member C9, Fe superoxide dismutase 2, 1 aminocyclopropane-1-carboxylate oxidase homolog 5, | Zeng et al. (2019) |
| Proteolysis: vacuolar-processing enzyme | ||||
| Different developmental stages (budding and mid-flowering) | Leaves | TMT labeling (nano-LC MS/MS) | Metabolites: D-mannose hemicellulose precursor (upregulated in mid flowering), L-phenylalanine, L-tyrosine, L-phenylalanine Metabolism: alpha glucosidase, alpha amylase Cell wall modification: UDP-glucuronic acid decarboxylase (xylan production), cinnamyl alcohol dehydrogenase (lignin biosynthesis) | Fan et al. (2018) |
| Fall dormancy | Terminal buds of fall dormant and non-fall dormant cultivars | iTRAQ (SCX fractionation, LC MS/MS) | Nitrogen metabolism: L-asparaginase Auxin polar transport: stilbene synthase family protein, monothiol glutaredoxin-S17 protein Lignin biosynthesis: cinnamyl alcohol dehydrogenase Pyruvate metabolism and transport: pyruvate carrier protein | Du et al. (2018) |
| Vitamin B1 metabolism: thiazole biosynthetic enzyme |