MAPK regulates secondary metabolism and abiotic stress in horticultural and medicinal plants

Abstract

Horticultural and medicinal plants are important for their economic and pharmacological value; however, their quality traits are severely affected by abiotic stresses. The mitogen-activated protein kinase (MAPK) cascade is an evolutionarily conserved signaling module that links abiotic stress signals to the regulation of plant quality traits. While the roles of MAPKs in growth, phytohormone signaling, and immunity are well established, a comprehensive review that integrates MAPK functions in abiotic stress responses and secondary metabolism, particularly in horticultural and medicinal plants, is still lacking. In this review, we systematically summarize (i) the composition, classification, and phylogenetic relationships of MAPKs in horticul- tural and medicinal plants; (ii) their mechanistic involvement in abiotic stress responses, particularly to salt, drought, and extreme temperatures; (iii) recent advances in understanding how MAPK-mediated signaling governs secondary metabolite accumulation; and (iv) a unified framework that presents MAPKs as a key bridge between stress responses and metabolic reprogramming. These insights provide a foundation for MAPK-targeted breeding and engineering strategies that enhance stress tolerance and improve quality traits in horticultural and medicinal plants through precise pathway manipulation.

Acknowledgements

This work was partially supported by the National Natural Science Foundation of China (No. 82173918) and the Young Scientists Innovation Funds of the State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology (2023HTDGZ-QN-02).

Author contributions

X.Y. and M.X. conceived and designed the review. S.L. and M.X. drafted the manuscript, prepared the figures, and compiled the tables. X.Y. and M.X. critically revised the manuscript. All authors reviewed and approved the final version.

Conflicts of interest statement

The authors declare that they have no competing interests.

Supplementary material

Supplementary material is available at Horticulture Research online.

References

[1] Mofokeng MM, Du Plooy CP, Araya HT. et al. Medicinal plant cultivation for sustainable use and commercialisation of high-value crops. S Afr J Sci. 2022; 118:1-7

[2] Alami MM, Guo S, Mei Z. et al. Environmental factors on secondary metabolism in medicinal plants: exploring accelerating factors. Med Plant Biol. 2024; 3:e016

[3] Tang H, Wang Q, Xie H. et al. The function of secondary metabolites in resisting stresses in horticultural plants. Fruit Res. 2024; 4:e021

[4] Rabeh K, Hnini M, Oubohssaine M. A comprehensive review of transcription factor-mediated regulation of secondary metabolites in plants under environmental stress. Stress Biol. 2025; 5:15

[5] Anzano A, Bonanomi G, Mazzoleni S. et al. Plant metabolomics in biotic and abiotic stress: a critical overview. Phytochem Rev. 2022; 21:503-24

[6] Haak DC, Fukao T, Grene R. et al. Multilevel regulation of abiotic stress responses in plants. Front Plant Sci. 2017; 8:1564

[7] Hanaka A, Majewska M, Jaroszuk-Ściseł J. Study of the influence of abiotic and biotic stress factors on horticultural plants. Horticulturae. 2021; 8:6

[8] Chen X, Ding Y, Yang Y. et al. Protein kinases in plant responses to drought, salt, and cold stress. J Integr Plant Biol. 2021; 63:53-78

[9] Del Río LA. ROS and RNS in plant physiology: an overview. J Exp Bot. 2015; 66:2827-37

[10] Dong Q, Wallrad L, Almutairi BO. et al. Ca ²⁺ signaling in plant responses to abiotic stresses. J Integr Plant Biol. 2022; 64:287-300

[11] Zhu JK. Abiotic stress signaling and responses in plants. Cell. 2016; 167:313-24

[12] Liu S, Zhang Q, Kolli L. et al. Molecular networks of secondary metabolism accumulation in plants: current understanding and future challenges. Ind Crop Prod. 2023; 201:116901

[13] Isah T. Stress and defense responses in plant secondary metabolites production. Biol Res. 2019; 52:39

[14] Upadhyay AL, Lambat P, Borthakur M. Secondary metabolite production in plants: in response to biotic and abiotic stress factors. J Adv Zool. 2024; 45:55-9

[15] Silva-Sanchez C, Li H, Chen S. Recent advances and challenges in plant phosphoproteomics. Proteomics. 2015; 15:1127-41

[16] Bigeard J, Hirt H. Nuclear signaling of plant MAPKs. Front Plant Sci. 2018; 9:469

[17] Mohanta TK, Arora PK, Mohanta N. et al. Identification of new members of the MAPK gene family in plants shows diverse conserved domains and novel activation loop variants. BMC Genomics. 2015; 16:58

[18] Cristina MS, Petersen M, Mundy J. Mitogen-activated protein kinase signaling in plants. Annu Rev Plant Biol. 2010; 61:621-49

[19] Li H, Chen N, Zhang H. et al. Multidimensional regulation of transcription factors: decoding the comprehensive signals of plant secondary metabolism. Front Plant Sci. 2025; 16:1522278

[20] Zhang M, Su J, Zhang Y. et al. Conveying endogenous and exogenous signals: MAPK cascades in plant growth and defense. Curr Opin Plant Biol. 2018; 45:1-10

[21] Xu J, Zhang S. Mitogen-activated protein kinase cascades in signaling plant growth and development. Trends Plant Sci. 2015; 20:56-64

[22] Dong G, Gui Z, Yuan Y. et al. Expression analysis of the extensive regulation of mitogen-activated protein kinase (MAPK) family genes in buckwheat (Fagopyrum tataricum ) during organ differentiation and stress response. Agronomy. 2024; 14:2613

[23] You X, Fan N, Zhang Y. et al. The MsNAC73-MsMPK3 complex modulates salt tolerance and shoot branching of alfalfa via activating MsPG2 and MsPAE12 expressions. Plant Biotechnol J. 2025; 23:5635-53

[24] Zhang Z, Liu H, Sun C. et al. A C2H 2 zinc-finger protein OsZFP213 interacts with OsMAPK 3 to enhance salt tolerance in rice. J Plant Physiol. 2018; 229:100-10

[25] Kishi-Kaboshi M, Okada K, Kurimoto L. et al. A rice fungal MAMP-responsive MAPK cascade regulates metabolic flow to antimicrobial metabolite synthesis. Plant J. 2010; 63:599-612

[26] Colcombet J, Hirt H. Arabidopsis MAPKs: a complex signalling network involved in multiple biological processes. Biochem J. 2008; 413:217-26

[27] Lei L, Li Y, Wang Q. et al. Activation of MKK9-MPK3/MPK6 enhances phosphate acquisition in Arabidopsis thaliana. New Phytol. 2014; 203:1146-60

[28] Danquah A, de Zélicourt A, Boudsocq M. et al. Identification and characterization of an ABA-activated MAP kinase cascade in Arabidopsis thaliana. Plant J. 2015; 82:232-44

[29] Li S, Wang W, Gao J. et al. MYB75 phosphorylation by MPK4 is required for light-induced anthocyanin accumulation in Arabidopsis. Plant Cell. 2016; 28:2866-83

[30] Luo J, Wang X, Feng L. et al. The mitogen-activated protein kinase kinase 9 (MKK9) modulates nitrogen acquisition and anthocyanin accumulation under nitrogen-limiting condition in Arabidopsis. Biochem Biophys Res Commun. 2017; 487:539-44

[31] Rohila JS, Yang Y. Rice mitogen-activated protein kinase gene family and its role in biotic and abiotic stress response. J Integr Plant Biol. 2007; 49:751-9

[32] Chen J, Wang L, Yuan M. Update on the roles of rice MAPK cascades. Int J Mol Sci. 2021; 22:1679

[33] Zhang Z, Li J, Li F. et al. OsMAPK3 phosphorylates OsbHLH002/OsICE1 and inhibits its ubiquitination to activate OsTPP1 and enhances rice chilling tolerance. Dev Cell. 2017; 43:731-743.e5

[34] Wang L, Xu J, Li L. et al. The OsBDR1-MPK3 module negatively regulates blast resistance by suppressing the jasmonate sig-naling and terpenoid biosynthesis pathway. Proc Natl Acad Sci USA. 2023; 120:e2211102120

[35] Ye T, Wang H, Zhang L. et al. A novel OsCRK14-OsRLCK57-MAPK signaling module activates OsbZIP66 to confer drought resistance in rice. Mol Plant. 2025; 18:1390-408

[36] Wang F, Jing W, Zhang W. The mitogen-activated protein kinase cascade MKK1-MPK4 mediates salt signaling in rice. Plant Sci. 2014; 227:181-9

[37] Zhang C, Zhu Z, Jiang A. et al. Genome-wide identification of the mitogen-activated kinase gene family from Limonium bicolor and functional characterization of LbMAPK 2 under salt stress. BMC Plant Biol. 2023; 23:565

[38] Liao J, Dong Y, Hua Z. etal. Identification of eggplant SmMPK gene family and functional verification of SmMPK4.1. Horticulturae. 2024; 10:239

[39] Tamura K, Stecher G, Kumar S. et al. MEGA11: molecular evolutionary genetics analysis version 11. Mol Biol Evol. 2021; 38:3022-7

[40] Song A, Hu Y, Ding L. et al. Comprehensive analysis of mitogen-activated protein kinase cascades in chrysanthemum. Peer J. 2018; 6:e5037

[41] Zhang S, Xu R, Luo X. et al. Genome-wide identification and expressionanalysis of MAPK and MAPKK gene family in Malus domestica. Gene. 2013; 531:377-87

[42] Xie Y, Ding M, Zhang B. et al. Genome-wide characterization and expression profiling of MAPK cascade genes in Salvia miltiorrhiza reveals the function of SmMAPK3 and SmMAPK 1 in secondary metabolism. BMC Genomics. 2020; 21:630

[43] Kong F, Wang J, Cheng L. et al. Genome-wide analysis of themitogen-activatedproteinkinasegenefamilyin Solanum lycopersicum. Gene. 2012; 499:108-20

[44] Çakır B, Kılıçkaya O. Mitogen-activated protein kinase cascades in Vitis vinifera. Front Plant Sci. 2015; 6:556

[45] Feller U, Vaseva II. Extreme climatic events: impacts of drought and high temperature on physiological processes in agronomically important plants. Front Environ Sci. 2014;2

[46] Shi Y, Zhang Z, Yan Z. et al. Tomato mitogen-activated protein kinase: mechanisms of adaptation in response to biotic and abiotic stresses. Front Plant Sci. 2025; 16:1533248

[47] Zhou Y, Singh SK, Patra B. et al. Mitogen-activated protein kinase-mediated regulation of plant specialized metabolism. J Exp Bot. 2025; 76:262-76

[48] Yang L, Zhang Y, Guan R. et al. Co-regulation of indole glucosinolates and camalexin biosynthesis by CPK5/CPK6 and MPK3/MPK 6 signaling pathways. J Integr Plant Biol. 2020; 62:1780-96

[49] Li Y, Cai H, Liu P. et al. Arabidopsis MAPKKK18 positively regulates drought stress resistance via downstream MAPKK3. Biochem Biophys Res Commun. 2017; 484:292-7

[50] Yu L, Nie J, Cao C. et al. Phosphatidic acid mediates salt stress response by regulation of MPK6 in Arabidopsis thaliana. New Phytol. 2010; 188:762-73

[51] Su S, Jiang Y, Zhu X. et al. Calcium-dependent protein kinases 5 and 13 enhance salt tolerance in rice by directly activating OsMPK3/6 kinases. Plant Physiol. 2024; 196:3033-47

[52] Ren N, Zhang G, Yang X. et al. MAPKKK 28 functions upstream of the MKK1-MPK1 cascade to regulate abscisic acid responses in rice. Plant, Cell & Environ. 2024; 47:5140-57

[53] Jia M, Luo N, Meng X. et al. OsMPK4 promotes phosphoryla-tion and degradation of IPA1 in response to salt stress to con-fer salt tolerance in rice. J Genet Genomics. 2022; 49:766-75

[54] Tang W, Tang AY. Overexpression of Arabidopsis thaliana malonyl-CoA synthetase gene enhances cold stress tolerance by activating mitogen-activated protein kinases in plant cells. J For Res. 2020; 32:741-53

[55] Zhao J, Zhu K, Chen M. et al. Identification and expression analysis of MPK and MKK gene families in pecan (Carya illinoiensis ). Int J Mol Sci. 2022; 23:15190

[56] Liu H, Li X, He F. et al. Genome-wide identification and analysis of abiotic stress responsiveness of the mitogen-activated protein kinase gene family in Medicago sativa L. BMC Plant Biol. 2024; 24:800

[57] Wei C, Liu X, Long D. et al. Molecular cloning and expression analysis of mulberry MAPK gene family. Plant Physiol Biochem. 2014; 77:108-16

[58] Kumar K, Raina SK, Sultan SM. Arabidopsis MAPK signaling pathways and their cross talks in abiotic stress response. J Plant Biochem Biotechnol. 2020; 29:700-14

[59] Li CH, Wang G, Zhao JL. et al. The receptor-like kinase SIT1 mediates salt sensitivity by activating MAPK3/6 and regulating ethylene homeostasis in rice. Plant Cell. 2014; 26:2538-53

[60] Yao Y, Zhao H, Sun L. et al. Genome-wide identification of MAPK gene family members in Fagopyrum tataricum and their expression during development and stress responses. BMC Genomics. 2022; 23:96

[61] Zhou HY, Ren SY, Han YF. et al. Identification and analysis of mitogen-activated protein kinase (MAPK) cascades in Fragaria vesca. Int J Mol Sci. 2017; 18:1766

[62] Neupane S, Schweitzer SE, Neupane A. et al. Identification and characterization of mitogen-activated protein kinase (MAPK ) genes in sunflower (Helianthus annuus L.). Plants. 2019; 8:28

[63] Wang G, Wang T, Jia ZH. et al. Genome-wide bioinformatics analysis of MAPK gene family in kiwifruit (Actinidia Chinensis ). Int J Mol Sci. 2018; 19:2510

[64] Gao P, Xiao J, Guo W. et al. Genome-wide identification of Glycyrrhiza uralensis Fisch. MAPK gene family and expression analysis under salt stress relieved by Bacillus subtilis. Front Genet. 2024; 15:1442277

[65] Sözen C, Schenk ST, Boudsocq M. et al. Wounding and insect feeding trigger two independent MAPK pathways with distinct regulation and kinetics. Plant Cell. 2020; 32:1988-2003

[66] Matsuoka D, Soga K, Yasufuku T. et al. Control of plant growth and development by overexpressing MAP3K17, an ABA-inducible MAP3K, in Arabidopsis. Plant Biotechnol. 2018; 35:171-6

[67] Umezawa T, Sugiyama N, Takahashi F. et al. Genetics and phosphoproteomics reveal a protein phosphorylation network in the abscisic acid signaling pathway in Arabidopsis thaliana. Sci Signal. 2013;6:rs8

[68] Ma H, Chen J, Zhang Z. et al. MAPK kinase 10.2 promotes disease resistance and drought tolerance by activating different MAPKs in rice. Plant J. 2017; 92:557-70

[69] Alfagham AT, Debnath S, Perveen K. et al. Computational analysis of albaflavenone interaction with SlMAPK1 for drought resistance in tomato. Mol Biotechnol. 2024; 67:2443-54

[70] Virk N, Liu B, Zhang H. et al. Tomato SlMPK4 is required for resistance against botrytis cinerea and tolerance to drought stress. Acta Physiol Plant. 2012; 35:1211-21

[71] Huang X, Wei J-M, Feng W-Z. et al. Interaction between SlMAPK3 and SlASR4 regulates drought resistance in tomato (Solanum lycopersicum L.). Mol Breed. 2023; 43:73

[72] Dong W, Xie Q, Li J. et al. BpMAPK3-mediated BpWRKY53 phosphorylation enhances Betula platyphylla drought stress tolerance by increasing flavonoid content. Plant J. 2025; 121:e70089

[73] Huang XS, Luo T, Fu XZ. et al. Cloning and molecular characterization of a mitogen-activated protein kinase gene from Poncirus trifoliata whose ectopic expression confers dehydration/drought tolerance in transgenic tobacco. J Exp Bot. 2011; 62:5191-206

[74] Weng CM, Lu JX, Wan HF. et al. Over-expression of BnMAPK1 in Brassica napus enhances tolerance to drought stress. J Integr Agric. 2014; 13:2407-15

[75] Zhou Y, Bai YH, Han F-X. et al. Transcriptome sequencing and metabolome analysis reveal the molecular mechanism of Salvia miltiorrhiza in response to drought stress. BMC Plant Biol. 2024; 24:446

[76] Zhou Y, Ma W, Bai Y. et al. The protein kinase SmSnRK2.7 mediates abscisic acid-regulated tanshinone biosynthesis under drought stress in Salvia miltiorrhiza. Ind Crop Prod. 2025; 235:121605

[77] Jiang S, Li H, Zhang L. et al. Generic diagramming platform (GDP): a comprehensive database of high-quality biomedical graphics. Nucleic Acids Res. 2025;53:D1670-6

[78] Zhao S, Zhang Q, Liu M. et al. Regulation of plant responses to salt stress. Int J Mol Sci. 2021; 22:4609

[79] Teige M, Scheikl E, Eulgem T. et al. The MKK2 pathway mediates cold and salt stress signaling in Arabidopsis. Mol Cell. 2004; 15:141-52

[80] Schmidt R, Mieulet D, Hubberten HM. et al. Salt-responsive ERF1 regulates reactive oxygen species-dependent signaling during the initial response to salt stress in rice. Plant Cell. 2013; 25:2115-31

[81] Li J, Zhang C, Miao Y. et al. Mitogen-activated protein kinase 7 phosphorylates transcription factor ZmWRKY104 to enhance salt tolerance in maize. J Exp Bot. 2025; 76:4709-25

[82] Ding R, Li J, Wang J. et al. Molecular traits of MAPK kinases and the regulatory mechanism of GhMAPKK5 alleviating drought/salt stress in cotton. Plant Physiol. 2024; 196:2030-47

[83] Wang C, Shan D, Bai Y. et al. MdMAPK3-driven phosphorylation enhances MdWRKY17-mediated regulation of high-affinity K ⁺ transporter 1 MdHAK1 for salt tolerance in apple. Int J Biol Macromol. 2025; 316:144633

[84] Yin P, Wang H, Ye Z. et al. The ZmMPK3-ZmGRF1 module promotes maize growth by enhancing cell proliferation under salt stress. Sci Bull. 2025;S 2095-9273(25)00669-3

[85] Ji G, Lu Q, Yu Y. et al. Function identification of the mitogen-activated protein kinase gene CsMPK4 in cucumber. Chin J Biotechnol. 2025; 41:857-68

[86] Shi L, Shi W, Qiu Z. et al. CaMAPK1 plays a vital role in the regulation of resistance to Ralstonia solanacearum infection and tolerance to heat stress. Plants. 2024; 13:1775

[87] Ding H, Wu Y, Yuan G. et al. In-depth proteome analysis reveals multiple pathways involved in tomato SlMPK1-mediated high-temperature responses. Protoplasma. 2020; 257:43-59

[88] Ding H, He J, Wu Y. et al. The tomato mitogen-activated protein kinase SlMPK1 is as a negative regulator of the high-temperature stress response. Plant Physiol. 2018; 177:633-51

[89] Wang T, Liu M, Wu Y. et al. Genome-wide identification and expression analysis of MAPK gene family in lettuce (Lactuca sativa L. ) and functional analysis of LsMAPK4 in high-temperature-induced bolting. Int J Mol Sci. 2022; 23:11129

[90] Kim SH, Hussain S, Pham HTT. et al. Phosphorylation of auxin signaling repressor IAA8 by heat-responsive MPKs causes defective flower development. Plant Physiol. 2024; 196:2825-40

[91] Li H, Ding Y, Shi Y. et al. MPK3- and MPK6-mediated ICE1 phosphorylation negatively regulates ICE1 stability and freezing tolerance in Arabidopsis. Dev Cell. 2017; 43:630-642.e4

[92] Zhao C, Wang P, Si T. et al. MAP kinase cascades regulate the cold response by modulating ICE1 protein stability. Dev Cell. 2017; 43:618-629.e5

[93] Song J, Lin R, Tang M. et al. SlMPK1-and SlMPK2-mediated SlBBX17 phosphorylation positively regulates CBF-dependent cold tolerance in tomato. New Phytol. 2023; 239:1887-902

[94] Yu L, Yan J, Yang Y. et al. Enhanced tolerance to chilling stress in tomato by overexpression of a mitogen-activated protein kinase, SlMPK7. Plant Mol Biol Report. 2016; 34:76-88

[95] Park SU, Jung YJ, Kwon HJ. et al. IbMPK3/IbMPK6-mediated IbSPF1 phosphorylation promotes cold stress tolerance in sweet potato. Biochem Biophys Res Commun. 2025; 769:151893

[96] Meraj TA, Fu J, Raza MA. et al. Transcriptional factors regulate plant stress responses through mediating secondary metabolism. Genes. 2020; 11:346

[97] Xing Y, Sun W, Sun Y. et al. MPK6-mediated HY5 phosphorylation regulates light-induced anthocyanin accumulation in apple fruit. Plant Biotechnol J. 2022; 21:283-301

[98] Wang S, Wang T, Li Q. et al. Phosphorylation of MdERF17 by MdMPK4 promotes apple fruit peel degreening during light/dark transitions. Plant Cell. 2022; 34:1980-2000

[99] Mao W, Han Y, Chen Y. et al. Low temperature inhibits anthocyanin accumulation in strawberry fruit by activating FvMAPK3-induced phosphorylation of FvMYB10 and degradation of chalcone synthase 1. Plant Cell. 2022; 34:1226-49

[100] Bai Y, Shi K, Shan D. et al. The WRKY17-WRKY50 complex modulates anthocyanin biosynthesis to improve drought tolerance in apple. Plant Sci. 2024; 340:111965

[101] Yang C, Zhang P, Jiang P. et al. GmMYB4 positively regulates isoflavone biosynthesis via the GmMAPK6-GmMYB4-MBW module in soybean. Plant Biotechnol J. 2025

[102] Lin H, Chen Y, Nomura K. et al. An MKP-MAPK protein phosphorylation cascade controls vascular immunity in plants. Sci Adv. 2022;8:eabg8723

[103] Gui J, Luo L, Zhong Y. et al. Phosphorylation of LTF1, an MYB transcription factor in populus, acts as a sensory switch regulating lignin biosynthesis in wood cells. Mol Plant. 2019; 12:1325-37

[104] Yin X, Liu S, Zhang Y. et al. Rosmarinic acid synthase 1 phosphorylation by SmMAPK3 is required for salicylic acid-induced salvianolic acid accumulation in Salvia miltiorrhiza hairy roots. Plant Biotechnol J. 2025

[105] Xie Y, Ding M, Yin X. et al. MAPKK2/4/5/7-MAPK3-JAZs modulate phenolic acid biosynthesis in Salvia miltiorrhiza. Phytochemistry. 2022; 199:113177

[106] Qu R, Wang S, Wang X. et al. The jasmonate-responsive SmMPK3-SmWRKY33 module positively regulates tanshinone biosynthesis in Salvia miltiorrhiza. Plant Biotechnol J. 2025

[107] Tan X, Chen J, Zhang J. et al. Gene expression and interaction analysis of FsWRKY4 and FsMAPK3 in Forsythia suspensa. Plants. 2023; 12:3415

[108] Xie Q, Dong W, Wang M. et al. BpWRKY6 regulates insect resis-tance by affecting jasmonic acid and terpenoid synthesis in Betula platyphylla. Plant Biotechnol J. 2025; 23:3682-96

[109] Luo D, Wang T, Ye M. et al. Identification and characterization of Crocus sativus WRKY and its interacting MPK involved in crocins biosynthesis based on full-length transcriptome analysis. Ind Crop Prod. 2023; 197:116559

[110] Li Z, Wang W, Li G. et al. MAPK-mediated regulation of growth and essential oil composition in a salt-tolerant peppermint (Mentha piperita L.) under NaCl stress. Protoplasma. 2015; 253:1541-56

[111] Ma J, Wei L, Huang K. et al. Biosynthesis of sakuranetin regulated by OsMPK6-OsWRKY67-OsNOMT cascade enhances resistance to false smut disease. New Phytol. 2024; 245:1216-31

[112] Lu L, Fang J, Xia N. et al. Phosphorylation of the transcription factor OsNAC 29 by OsMAPK3 activates diterpenoid genes to promote rice immunity. Plant Cell. 2025;37:koae320

[113] Lin X, Ding C, Xiao W. et al. A molecular switch OsWRKY10-OsVQ8 orchestrates rice diterpenoid phytoalexin biosynthesis for broad-spectrum disease resistance. New Phytol. 2025; 246:2243-62

[114] Mao G, Meng X, Liu Y. et al. Phosphorylation of a WRKY transcription factor by two pathogen-responsive MAPKs drives phytoalexin biosynthesis in Arabidopsis. Plant Cell. 2011; 23:1639-53

[115] Raina SK, Wankhede DP, Singh P. et al. CrMPK3, a mitogen activated protein kinase from Catharanthus roseus and its possible role in stress induced biosynthesis of monoterpenoid indole alkaloids. BMC Plant Biol. 2012; 12:134

[116] Paul P, Singh SK, Patra B. et al. A differentially regulated AP2/ERF transcription factor gene cluster acts downstream of a MAP kinase cascade to modulate terpenoid indole alkaloid biosynthesis in Catharanthus roseus. New Phytol. 2017; 213:1107-23

[117] Liu X, Singh SK, Patra B. et al. Protein phosphatase NtPP2C2b and MAP kinase NtMPK4 act in concert to modulate nicotine biosynthesis. J Exp Bot. 2021; 72:1661-76

[118] Zhou Y, Liu Y, Lyu R. et al. Post-translational control of biotic stress-related nicotine biosynthesis by a MAP kinase signaling cascade. Crop J. 2025

[119] Xie G, Kato H, Imai R. Biochemical identification of the OsMKK6-OsMPK3 signalling pathway for chilling stress tolerance in rice. Biochem J. 2012; 443:95-102

[120] Wang L, Zhao R, Li R. et al. Enhanced drought tolerance in tomato plants by overexpression of SlMAPK1. Plant Cell Tiss Org. 2018; 133:27-38

[121] Zheng T, Li Y, Lei W. et al. SUMO E3 ligase SIZ1 stabilizes MYB75 to regulate anthocyanin accumulation under high light conditions in Arabidopsis. Plant Sci. 2020; 292:110355

[122] Maier A, Schrader A, Kokkelink L. et al. Light and the E3 ubiquitin ligase COP 1/SPA control the protein stability of the MYB transcription factors PAP 1 and PAP 2 involved in anthocyanin accumulation in Arabidopsis. Plant J. 2013; 74:638-51

[123] Friso G, Wijk KJV. Post-translational protein modifications in plant metabolism. Plant Physiol. 2015; 169:01378.2015-87