Table 3. The differential proteins identified in the epidermises in red onion (spots 1–30) and yellow onion (spots 31–47).
| Spot | Homolog proteins(Plant species) | Accession a | Location b | Molecular function |
|---|---|---|---|---|
| Proteins in increased abundance in LE | ||||
| Pigment biosynthesis | ||||
| 17 | Flavone O-methyltransferase 1-like (Musa acuminata) | M0SIB3 | *Plastid | O-methyltransferase activity |
| 28 | Chalcone-flavanone isomerase (Allium cepa) | Q6QHK0 | Tonoplast, Nucleus, ER | Secondary metabolite (e.g., flavonoids) biosynthesis |
| 43 | Chalcone-flavanone isomerase (A. cepa) | Q6QHK0 | Tonoplast, Nucleus, ER | Secondary metabolite (e.g., flavonoids) biosynthesis |
| Stress response | ||||
| 13 | GDP-mannose 3',5'-epimerase 1 (Oryza sativa) | A3C4S4 | *Cytoplasm | GDP-mannose 3,5-epimerase activity, coenzyme binding |
| 14 | Formate dehydrogenase 1 (O. brachyantha) | J3ME94 | Plastid, Thylakoid | Oxidoreductase activity, NAD binding |
| 16 | Trans-resveratrol di-O-methyltransferase-like (Elaeis guineensis) | UPI00057A5A6F | *Cytoplasm, Plastid, Mitochondrion | Trans-resveratrol di-O-methyltransferase |
| 19, 20, 23 | Momilactone A synthase-like (Zea mays) | A0A096R062 | *Plastid | Oxidoreductase activity |
| 22 | Chitinase (Allium sativum) | Q38777 | *Extracellular space, Vacuole | Chitinase activity, chitin binding |
| 30 | Peroxiredoxin-5 (Z. mays) | B4FN24 | *Cytoplasm | Oxidoreductase activity |
| 36 | Trans-resveratrol di-O-methyltransferase-like (E. guineensis) | UPI00057A5A6F | *Cytoplasm, Plastid, Mitochondrion | Trans-resveratrol di-O-methyltransferase |
| 47 | Tau glutathione S-transferase (A. cepa) | F2ZC01 | *Cytoplasm | Transferase activity |
| Carbohydrate metabolism | ||||
| 4, 5 | Malic enzyme (O. sativa) | Q6T5D1 | *Cytoplasm, Plastid | Malate dehydrogenase (NAD+) (decarboxylating) activity, metal ion binding |
| 6 | 2,3-bisphosphoglycerat independent phosphoglycerate mutase (Z. mays) | C0HHU2 | Cytoplasm | Phosphoglycerate mutase activity, Mg2+ binding |
| 33 | 2,3-bisphosphoglycerat independent phosphoglycerate mutase (Z. mays) | C0HHU2 | Cytoplasm | Phosphoglycerate mutase activity, Mg2+ binding |
| 34 | Enolase1 (Z. mays) | K7V794 | Phosphopyruvate hydratase complex | Phosphopyruvate hydratase activity, Mg2+ binding |
| Cell division | ||||
| 18 | UDP-arabinopyranose mutase 1-like (O. brachyantha) | J3LQM6 | Golgi apparatus, Cytoplasm | Intramolecular transferase activity |
| Protein synthesis | ||||
| 1 | Translation elongation factor EF-2 subunit (Z. mays) | B6U0S1 | *Cytoplasm | GTPase activity, translation elongation factor activity, nucleotide binding |
| 2, 3 | 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase 2 (O. sativa) | Q2QLY4 | *Cytosol | 5-methyltetrahydropteroyltriglutamate-homocysteine S-methyltransferase activity, Zn2+ binding |
| 7 | D-3-phosphoglycerate dehydrogenase (O. sativa) | A3BE72 | *Plastid | Amino acid binding, NAD binding, phosphoglycerate dehydrogenase activity |
| 8 | D-3-phosphoglycerate dehydrogenase (Z. mays) | A0A096R8F6 | *Plastid | Amino acid binding, NAD binding, phosphoglycerate dehydrogenase activity |
| 11 | Serine hydroxymethyltransferase (O. brachyantha) | J3N865 | *Plasmodesma Cytoplasm, Membrane | Pyridoxal phosphate binding, glycine hydroxymethyltransferase activity |
| 15 | Glutamine synthetase root isozyme 5 (Z. mays) | P38563 | Cytoplasm | ATP binding, glutamate ammonia ligase activity |
| 31, 32 | 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase 2 (O. sativa) | Q2QLY4 | Cytosol | 5-methyltetrahydropteroyltriglutamate-homocysteine S-methyltransferase activity, Zn2+ binding |
| 37 | Protein disulfide isomerase like 2–2 (M. acuminata) | M0RS28 | ER | Isomerase activity |
| Proteins in increased abundance in UE | ||||
| Stress response | ||||
| 21 | Chitinase, partial (A. sativum) | Q38776 | *Vacuole, Extracellular space | Chitinase activity, chitin binding |
| 24, 25 | Beta-1,3-glucanase (Lilium) | Q1W6B9 | *Extracellular space | Hydrolase activity, hydrolyzing O-glycosyl compounds |
| 26 | Salicylic acid-binding protein 2-like (E. guineensis) | UPI00057B4D46 | *Plastid | Lipase activity, methyl salicylate esterase activity |
| 29 | Pathogenesis-related protein 5(A. sativum) | A0A0K1L9H1 | *Vacuole | Pathogenesis-related protein, plant defense |
| 38 | Hydroxyacylglutathione hydrolase cytoplasmic-like isoform X1 (O. brachyantha) | J3LNG8 | Cytosol | Hydroxyacylglutathione hydrolase activity |
| 39, 41 | Beta-1,3-glucanase (Lilium) | Q1W6B9 | *Extracellular space | Hydrolase activity, hydrolyzing O-glycosyl compounds |
| 40 | Chitinase (A. sativum) | Q38777 | *Vacuole, Extracellular space | Chitinase activity, chitin binding |
| 42 | Thaumatin-like protein 1b (Z. mays) | A0A096QLD7 | *Vacuole | Allergenic/antifungal thaumatin-like proteins |
| 44, 45 | Pathogenesis-related protein 5 (A. sativum) | A0A0K1L9H1 | Vacuole | Pathogenesis-related protein, plant defense |
| 46 | Intracellular pathogenesis related protein (Asparagus officinalis) | Q9SB87 | *Cytoplasm | Pathogenesis-related protein |
| Carbohydrate metabolism | ||||
| 9 | ATP synthase subunit alpha (A. cepa) | D2XT90 | Mitochondrion | Proton-transporting ATPase activity, ATP binding |
| 10 | Vacuolar ATP synthase subunit B (Z. mays) | B6T9C0 | Vacuole | ATP binding, hydrolase activity |
| 12 | Enolase (Z. mays) | B6T3P9 | Phosphopyruvate hydratase complex | Phosphopyruvate hydratase activity, Mg2+ binding |
| 35 | Enolase (Z. mays) | B6T3P9 | Phosphopyruvate hydratase complex | Phosphopyruvate hydratase activity, Mg2+ binding |
| Others | ||||
| 27 | Lachrymatory factor synthase (A. cepa) | P59082 | Vacuole | Lachrymatory factor synthase activity |
a UniProtKB/UniRef accession;
b Subcellular localization of proteins annotated in UniProtKB/Swiss-Prot (http://www.uniprot.org/) except those with asterisk mark which were predicte d in online Plant-mPLoc server (http://www.csbio.sjtu.edu.cn/bioinf/plant-multi/).