Journal of Plant Biology

, Volume 61, Issue 2, pp 97–110 | Cite as

The Arabidopsis Mediator Complex Subunit MED19a is Involved in ABI5-mediated ABA Responses

  • Xiaohui Li
  • Rui Yang
  • Yifu Gong
  • Haimin Chen
Original Article


Arabidopsis Mediator complex subunit 19a (MED19a), which mediates interactions between transcriptional regulators and RNA polymerase II, plays a critical role in plant response to infection by pathogens. However, the roles of MED19a in other signaling pathways are unknown. Here, we report that MED19a plays an important role in regulation of abscisic acid (ABA)-mediated transcriptional regulation in Arabidopsis. Plants deficient in MED19a showed reduced sensitivity to ABA inhibition of seed germination, cotyledon greening, root growth, and stomatal opening. MED19a-deficient mutants also had reduced resistance to drought stress, evidenced by high water-loss rates and low survival rates. Molecular genetic analysis revealed that MED19a mutants had down-regulated ABA-induced genes, including Em1, Em6, and RD29B, and MED19a could occupy the promoters of Em1 and Em6 in an ABA-dependent manner. Furthermore, MED19a interacted with the transcription factor ABA-insensitive 5 (ABI5) in split-luciferase complementation assays and co-immunoprecipitation assays. An analysis of double mutants (med19a-2 and abi5-7) suggested that the action of MED19a in ABA signaling was dependent upon ABI5. Furthermore, MED19a and ABI5 influenced each other in recruiting the promoters of the target genes Em1 and Em6, which are involved in embryonic development. Altogether, these results indicate that MED19a acts as a positive regulator in ABI5-mediated ABA responses.


ABA responses ABI5 Mediator complex MED19a Transcription regulation 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Supplementary material

12374_2017_277_MOESM1_ESM.doc (1.6 mb)
Supplementary material, approximately 1663 KB.


  1. Allen BL, Taatjes DJ (2015) The Mediator complex: a central integrator of transcription. Nat Rev Mol Cell Bio 16: 155−166CrossRefGoogle Scholar
  2. Atkinson NJ, Urwin PE (2012) The interaction of plant biotic and abiotic stresses: from genes to the field. J Exp Bot 63: 3523−3543Google Scholar
  3. Autran D, Jonak C, Belcram K, Beemster GT, Kronenberger J, Grandjean O, Inze D, Traas J (2002) Cell numbers and leaf development in Arabidopsis:a functional analysis of the STRUWWELPETER gene. EMBO J 21: 6036−6049CrossRefPubMedCentralGoogle Scholar
  4. Bäckström S, Elfving N, Nilsson R, Wingsle G, Björklund S (2007) Purification of a plant mediator from Arabidopsis thaliana identifies PFT1 as the Med25 subunit. Mol Cell 26: 717–729CrossRefPubMedGoogle Scholar
  5. Bonawitz ND, Soltau WL, Blatchley MR, Powers BL, Hurlock AK, Seals LA, Weng JK, Stout J, Chapple C (2012) REF4 and RFR1, subunits of the transcriptional coregulatory complex mediator, are required for phenylpropanoid homeostasis in Arabidopsis. J Biol Chem 287: 5434–5445CrossRefPubMedGoogle Scholar
  6. Bright J, Desikan R, Hancock JT, Weir LS, Neill SJ (2006) ABAinduced NO generation and stomatal closure in Arabidopsis are dependent on H2O2 synthesis. Plant J 45: 113–122CrossRefPubMedGoogle Scholar
  7. Brocard IM, Lynch TJ, Finkelstein RR (2002) Regulation and role of the Arabidopsis abscisic acid-insensitive 5 gene in abscisic acid, sugar, and stress response. Plant Physiol 129: 1533–1543CrossRefPubMedPubMedCentralGoogle Scholar
  8. Bu Q, Li H, Zhao Q, Jiang H, Zhai Q, Zhang J, Wu X, Sun J, Xie Q, Wang D, Li C (2009) The Arabidopsis RING finger E3 ligase RHA2a is a novel positive regulator of abscisic acid signaling during seed germination and early seedling development. Plant Physiol 150: 463–481CrossRefPubMedPubMedCentralGoogle Scholar
  9. Bu Q, Lv T, Shen H, Luong P, Wang J, Wang Z, Huang Z, Xiao L, Engineer C, Kim T, Schroeder J, Huq E (2014) Regulation of drought tolerance by the F-box protein MAX2 in Arabidopsis. Plant Physiol 164: 424–439CrossRefPubMedGoogle Scholar
  10. Caillaud MC, Asai S, Rallapalli G, Piquerez S, Fabro G, Jones JD (2013) A downy mildew effector attenuates salicylic acid-triggered immunity in Arabidopsis by interacting with the host mediator complex. PLoS Biol 11: e1001732CrossRefPubMedPubMedCentralGoogle Scholar
  11. Canet JV, Dobon A, Tornero P (2012) Non-recognition-of-BTH4, an Arabidopsis mediator subunit homolog, is necessary for development and response to salicylic acid. Plant Cell 24: 4220–4235CrossRefPubMedPubMedCentralGoogle Scholar
  12. Carles C, Bies-Etheve N, Aspart L, Leon-Kloosterziel KM, Koornneef M, Echeverria M, Delseny M (2002) Regulation of Arabidopsis thaliana Em genes: role of ABI5. Plant J 30: 373–383CrossRefPubMedGoogle Scholar
  13. Chai YM, Jia HF, Li CL, Dong QH, Shen YY (2011) FaPYR1 is involved in strawberry fruit ripening. J Exp Bot 62: 5079–5089CrossRefPubMedGoogle Scholar
  14. Chen R, Jiang HL, Li L, Zhai QZ, Qi LL, Zhou WK, Liu XQ, Li HM, Zheng WG, Sun JQ, Li CY (2012) The Arabidopsis mediator subunit MED25 differentially regulates jasmonate and abscisic acid signaling through interacting with the MYC2 and ABI5 transcription factors. Plant Cell 24: 2898–2916CrossRefPubMedPubMedCentralGoogle Scholar
  15. Chhun T, Chong SY, Park BS, Wong EC, Yin JL, Kim M, Chua NH (2016) HSI2 repressor recruits MED13 and HDA6 to downregulate seed maturation gene expression directly during Arabidopsis early seedling growth. Plant Cell Physiol 57: 1689–1706CrossRefPubMedGoogle Scholar
  16. Choi DS, Hwang BK (2011) Proteomics and functional analyses of pepper abscisic acid–responsive 1 (ABR1), which is involved in cell death and defense signaling. Plant Cell 23: 823–842CrossRefPubMedPubMedCentralGoogle Scholar
  17. Clough SJ, Bent AF (1998) Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana. Plant J 16: 735–743CrossRefPubMedGoogle Scholar
  18. Cohen AC, Bottini R, Pontin M, Berli FJ, Moreno D, Boccanlandro H, Travaglia CN, Piccoli PN (2015) Azospirillum brasilense ameliorates the response of Arabidopsis thaliana to drought mainly via enhancement of ABA levels. Physiol Plantarum 153: 79–90CrossRefGoogle Scholar
  19. Conaway RC, Conaway JW (2011) Function and regulation of the Mediator complex. Curr Opin Genet Dev 21: 225–230CrossRefPubMedPubMedCentralGoogle Scholar
  20. Cutler SR, Rodriguez PL, Finkelstein RR, Abrams SR (2010) Abscisic acid: emergence of a core signaling network. Annu Rev Plant Biol 61: 651–679CrossRefPubMedGoogle Scholar
  21. Dhawan R, Luo H, Foerster AM, Abuqamar S, Du HN, Briggs SD, Mittelsten SO, Mengiste T (2009) HISTONE MONOUBIQUI TINATION1 interacts with a subunit of the mediator complex and regulates defense against necrotrophic fungal pathogens in Arabidopsis. Plant Cell 21: 1000–1019CrossRefPubMedPubMedCentralGoogle Scholar
  22. Elfving N, Davoine C, Benlloch R, Blomberg J, Brannstrom K, Muller D, Nilsson A, Ulfstedt M, Ronne H, Wingsle G, Nilsson O, Bjorklund S (2011) The Arabidopsis thaliana Med25 mediator subunit integrates environmental cues to control plant development. Proc Natl Acad Sci USA 108: 8245–8250CrossRefPubMedPubMedCentralGoogle Scholar
  23. Finkelstein RR, Lynch TJ (2000) The Arabidopsis abscisic acid response gene ABI5 encodes a basic leucine zipper transcription factor. Plant Cell 12: 599–609CrossRefPubMedPubMedCentralGoogle Scholar
  24. Finkelstein RR, Wang ML, Lynch TJ, Rao S, Goodman HM (1998) The Arabidopsis abscisic acid response locus ABI4 encodes an APETALA2 domain protein. Plant Cell 10: 1043–1054PubMedPubMedCentralGoogle Scholar
  25. Fujii H, Chinnusamy V, Rodrigues A, Rubio S, Antoni R, Park SY, Cutler SR, Sheen J, Rodriguez PL, Zhu JK (2009) In vitro reconstitution of an abscisic acid signaling pathway. Nature 462: 660–664CrossRefPubMedPubMedCentralGoogle Scholar
  26. Garciamata C, Lamattina L (2001) Nitric Oxide Induces Stomatal Closure and Enhances the Adaptive Plant Responses against Drought Stress. Plant Physiol 126: 1196–1204CrossRefGoogle Scholar
  27. Gillmor CS, Park MY, Smith MR, Pepitone R, Kerstetter RA, Poethig RS (2010) The MED12-MED13 module of Mediator regulates the timing of embryo patterning in Arabidopsis. Development 137: 113–122CrossRefPubMedPubMedCentralGoogle Scholar
  28. Giraudat J, Hauge BM, Valon C, Smalle J, Parcy F, Goodman HM (1992) Isolation of the arabidopsis ABI3 gene by positional cloning. Plant Cell 4: 1251–1261CrossRefPubMedPubMedCentralGoogle Scholar
  29. Hemsley PA, Hurst CH, Kaliyadasa E, Lamb R, Knight MR, De Cothi EA, Steele JF, Knight H (2014) The Arabidopsis mediator complex subunits MED16, MED14, and MED2 regulate mediator and RNA polymerase II recruitment to CBF-responsive coldregulated genes. Plant Cell 20: 9812–9841Google Scholar
  30. Ito J, Sono T, Tasaka M, Furutani M (2011) MACCHI-BOU 2 is required for early embryo patterning and cotyledon organogenesis in Arabidopsis. Plant Cell Physiol 52: 539–552CrossRefPubMedGoogle Scholar
  31. Johnson JM, Reichelt M, Vadassery J, Gershenzon J, Oelmuller R (2014) An Arabidopsis mutant impaired in intracellular calcium elevation is sensitive to biotic and abiotic stress. BMC Plant Biol 14: 1CrossRefGoogle Scholar
  32. Kidd BN, Edgar CI, Kumar KK, Aitken EA, Schenk PM, Manners JM, Kazan K (2009) The mediator complex subunit PFT1 is a key regulator of jasmonate-dependent defense in Arabidopsis. Plant Cell 21: 2237–2252CrossRefPubMedPubMedCentralGoogle Scholar
  33. Kim MJ, Jang IC, Chua NH (2016) MED15 subunit mediates activation of downstream lipid-related genes by Arabidopsis WRINKLED1. Plant Physiol 171: 1951–1964CrossRefPubMedPubMedCentralGoogle Scholar
  34. Kim YJ, Zheng B, Yu Y, Won SY, Mo B, Chen X (2011) The role of Mediator in small and long noncoding RNA production in Arabidopsis thaliana. EMBO J 30: 814–822CrossRefPubMedPubMedCentralGoogle Scholar
  35. Knight H, Thomson AJ, McWatters HG (2008) Sensitive to freezing6 integrates cellular and environmental inputs to the plant circadian clock. Plant Physiol 148: 293–303CrossRefPubMedPubMedCentralGoogle Scholar
  36. Lai ZB, Schluttenhofer CM, Bhide K, Shreve J, Thimmapuram J, Lee Y, Yun DJ, Mengiste T (2014) MED18 interaction with distinct transcription factors regulates multiple plant functions. Nat Commun 5: 3064CrossRefPubMedGoogle Scholar
  37. Li HM, Jiang HL, Bu QY, Zhao QZ, Sun JQ, Xie Q, Li CY (2011) The Arabidopsis RING finger E3 ligase RHA2b acts additively with RHA2a in regulating abscisic acid signaling and drought response. Plant Physiol 156: 550–563CrossRefPubMedPubMedCentralGoogle Scholar
  38. Li X, Huang L, Zhang YF, Ouyang ZG, Hong YB, Zhang HJ, Li DY, Song FM (2014) Tomato SR/CAMTA transcription factors SlSR1 and SlSR3L negatively regulate disease resistance response and SlSR1L positively modulates drought stress tolerance. BMC Plant Biol 14: 1CrossRefGoogle Scholar
  39. Li W, Yoshida A, Takahashi M, Maekawa M, Kojima M, Sakakibara H, Kyozuka J (2015) SAD1, an RNA polymerase I subunit A34.5 of rice, interacts with Mediator and controls various aspects of plant development. Plant J 81: 282–291CrossRefPubMedGoogle Scholar
  40. Linster E, Stephan I, Bienvenut WV, Maple-Grodem J, Myklebust LM, Huber M, Reichelt M, Sticht C, Moller SG, Meinnel T, Arnesen T, Giglione C, Hell R, Wirtz M (2015) Downregulation of N-terminal acetylation triggers ABA-mediated drought responses in Arabidopsis. Nat Commun 6: 7640CrossRefPubMedPubMedCentralGoogle Scholar
  41. Luo YJ, Wang ZJ, Ji HT, Fang H, Wang SF, Tian LN, Li X (2013) An Arabidopsis homolog of importin β1 is required for ABA response and drought tolerance. Plant J 75: 377–389CrossRefPubMedGoogle Scholar
  42. Ma Y, Szostkiewicz I, Korte A, Moes D, Yang Y, Christmann A, Grill E (2009) Regulators of PP2C phosphatase activity function as abscisic acid sensors. Science 324: 1064–1068PubMedGoogle Scholar
  43. Melcher K, Ng LM, Zhou XE, Soon FF, Xu Y, Suino-Powell KM, Park SY, Weiner JJ, Fujii H, Chinnusamy V, Kovach A, Li J, Wang YH, Li JY, Peterson FC, Jensen DR, Yong EL, Volkman BF, Cutler SR, Zhu JK, Xu HE (2009) A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors. Nature 462: 602–608CrossRefPubMedPubMedCentralGoogle Scholar
  44. Melotto M, Underwood W, Koczan J, Nomura K, He SY (2006) Plant stomata function in innate immunity against bacterial invasion. Cell 126: 969–980CrossRefPubMedGoogle Scholar
  45. Merlot S, Gosti F, Guerrier D,Vavasseur A, Giraudat J (2001) The ABI1 and ABI2 protein phosphatases 2C act in a negative feedback regulatory loop of the abscisic acid signalling pathway. Plant J 25: 295–303CrossRefPubMedGoogle Scholar
  46. Miyazono K, Miyakawa T, Sawano Y, Kubota K, Kang HJ, Asano A,Miyauchi Y, Takahashi M, Zhi YH,Fujita Y, Yoshida T, Kodaira KS, Yamaguchi-Shinozaki K, Tanokura M (2009) Structural basis of abscisic acid signalling. Nature 462: 609–614CrossRefPubMedGoogle Scholar
  47. Murashige T, Skoog F (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol Plant 15: 473–497CrossRefGoogle Scholar
  48. Nambara E, Suzuki M, Abrams S, McCarty DR, Kamiya Y, McCourt P (2002) A screen for genes that function in abscisic acid signaling in Arabidopsis thaliana. Genetics 161: 1247–1255PubMedPubMedCentralGoogle Scholar
  49. Nambara E, Okamoto M, Tatematsu K, Yano R, Seo M, Kamiya Y (2010) Abscisic acid and the control of seed dormancy and germination. Seed Sci Res 20: 55–67CrossRefGoogle Scholar
  50. Park SY, Fung P, Nishimura N, Jensen DR, Fujii H, Zhao Y, Lumba S, Santiago J, Rodrigues A, Chow TFF, Alfred SE, Bonetta D, Finkelstein R, Provart NJ, Desveaux D, Rodriguez PL, McCourt P, Zhu JK, Schroeder JI, Volkman BF, Cutler SR (2009) Abscisic acid inhibits type 2C protein phosphatases via the PYR/PYL family of START proteins. Science 324: 1068–1071PubMedPubMedCentralGoogle Scholar
  51. Santiago J, Dupeux F, Round A, Antoni R, Park SY, Jamin M, Cutler SR, Rodriguez PL, Marquez JA (2009) The abscisic acid receptor PYR1 in complex with abscisic acid. Nature 462: 665–668CrossRefPubMedGoogle Scholar
  52. Schroeder JI, Kwak JM, Allen GJ (2001) Guard cell abscisic acid signalling and engineering drought hardiness in plants. Nature 410: 327–330CrossRefPubMedGoogle Scholar
  53. Shinozaki K, Yamaguchi-Shinozaki K (2007) Gene networks involved in drought stress response and tolerance. J Exp Bot 58: 221–227CrossRefPubMedGoogle Scholar
  54. Tamura N, Yoshida T, Tanaka A, Sasaki R, Bando A, Toh S, Lepiniec L, Kawakami N (2006) Isolation and characterization of high temperature-resistant germination mutants of Arabidopsis thaliana. Plant Cell Physiol 47: 1081–1094CrossRefPubMedGoogle Scholar
  55. Trivedi DK, Gill SS, Tuteja N (2016) Abscisic acid (ABA): Biosynthesis, regulation and role in abiotic stress tolerance. In Tuteja N, Gill SS, eds, Plant Responses to Stress Signaling, Wiley Wiley-VCH Verlag GmbH & Co. Weinheim, Germany, pp 311–322Google Scholar
  56. Yoshida T, Fujita Y, Sayama H, Kidokoro S, Maruyama K, Mizoi J, Shinozaki K, Yamaguchi-Shinozaki K (2010) AREB1, AREB2, and ABF3 are master transcription factors that cooperatively regulate ABRE-dependent ABA signaling involved in drought stress tolerance and require ABA for full activation. Plant J 61: 672–685CrossRefPubMedGoogle Scholar
  57. Yu LX, Setter TL (2003) Comparative transcriptional profiling of placenta and endosperm in developing maize kernels in response to water deficit. Plant Physiol 131: 568–582CrossRefPubMedPubMedCentralGoogle Scholar
  58. Zhai QZ, Zhang X, Wu FM, Feng HL, Deng L, Xu L, Zhang M, Wang QM, Li CY (2015). Transcriptional mechanism of jasmonate receptor COI1-mediated delay of flowering time in Arabidopsis. Plant Cell 27: 2814–2828Google Scholar
  59. Zhang X, Wang C, Zhang Y, Sun Y, Mou Z (2012) The Arabidopsis mediator complex subunit 16 positively regulates salicylatemediated systemic acquired resistance and jasmonate/ethyleneinduced defense pathways. Plant Cell 24: 4294–4309CrossRefPubMedPubMedCentralGoogle Scholar
  60. Zhang X, Yao J, Zhang Y, Sun Y, Mou Z (2013) The Arabidopsis mediator complex subunits MED14/SWP and MED16/SFR6/ IEN1 differentially regulate defense gene expression in plant immune responses. Plant J 75: 484–497CrossRefPubMedGoogle Scholar
  61. Zhao Y, Chan Z, Gao J, Xing L, Cao M, Yu C, Hu Y, You J, Shi H, Zhu Y, Gong Y, Mu Z, Wang H, Deng X, Wang P, Bressan RA, Zhu JK (2016) ABA receptor PYL9 promotes drought resistance and leaf senescence. Proc Natl Acad Sci USA 113: 1949–1954CrossRefPubMedPubMedCentralGoogle Scholar
  62. Zhu YF, Schluttenhoffer CM, Wang PC, Fu FY, Thimmapuram J, Zhu JK, Lee SY, Yun DJ, Mengiste T (2014) CYCLIN-DEPENDENT KINASE8 differentially regulates plant immunity to fungal pathogens through kinase dependent and independent functions. Plant Cell 26: 4149–4170CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© Korean Society of Plant Biologists and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Key Laboratory of Applied Marine BiotechnologyNingbo UniversityNingbo, ZhejiangChina

Personalised recommendations