Abstract
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.
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References
Allen BL, Taatjes DJ (2015) The Mediator complex: a central integrator of transcription. Nat Rev Mol Cell Bio 16: 155−166
Atkinson NJ, Urwin PE (2012) The interaction of plant biotic and abiotic stresses: from genes to the field. J Exp Bot 63: 3523−3543
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: 6036−6049
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: 717–729
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: 5434–5445
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: 113–122
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: 1533–1543
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: 463–481
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: 424–439
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: e1001732
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: 4220–4235
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: 373–383
Chai YM, Jia HF, Li CL, Dong QH, Shen YY (2011) FaPYR1 is involved in strawberry fruit ripening. J Exp Bot 62: 5079–5089
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: 2898–2916
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: 1689–1706
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: 823–842
Clough SJ, Bent AF (1998) Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana. Plant J 16: 735–743
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: 79–90
Conaway RC, Conaway JW (2011) Function and regulation of the Mediator complex. Curr Opin Genet Dev 21: 225–230
Cutler SR, Rodriguez PL, Finkelstein RR, Abrams SR (2010) Abscisic acid: emergence of a core signaling network. Annu Rev Plant Biol 61: 651–679
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: 1000–1019
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: 8245–8250
Finkelstein RR, Lynch TJ (2000) The Arabidopsis abscisic acid response gene ABI5 encodes a basic leucine zipper transcription factor. Plant Cell 12: 599–609
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: 1043–1054
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: 660–664
Garciamata C, Lamattina L (2001) Nitric Oxide Induces Stomatal Closure and Enhances the Adaptive Plant Responses against Drought Stress. Plant Physiol 126: 1196–1204
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: 113–122
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: 1251–1261
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: 9812–9841
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: 539–552
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: 1
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: 2237–2252
Kim MJ, Jang IC, Chua NH (2016) MED15 subunit mediates activation of downstream lipid-related genes by Arabidopsis WRINKLED1. Plant Physiol 171: 1951–1964
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: 814–822
Knight H, Thomson AJ, McWatters HG (2008) Sensitive to freezing6 integrates cellular and environmental inputs to the plant circadian clock. Plant Physiol 148: 293–303
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: 3064
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: 550–563
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: 1
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: 282–291
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: 7640
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: 377–389
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: 1064–1068
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: 602–608
Melotto M, Underwood W, Koczan J, Nomura K, He SY (2006) Plant stomata function in innate immunity against bacterial invasion. Cell 126: 969–980
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: 295–303
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: 609–614
Murashige T, Skoog F (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol Plant 15: 473–497
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: 1247–1255
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: 55–67
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: 1068–1071
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: 665–668
Schroeder JI, Kwak JM, Allen GJ (2001) Guard cell abscisic acid signalling and engineering drought hardiness in plants. Nature 410: 327–330
Shinozaki K, Yamaguchi-Shinozaki K (2007) Gene networks involved in drought stress response and tolerance. J Exp Bot 58: 221–227
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: 1081–1094
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 311–322
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: 672–685
Yu LX, Setter TL (2003) Comparative transcriptional profiling of placenta and endosperm in developing maize kernels in response to water deficit. Plant Physiol 131: 568–582
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: 2814–2828
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: 4294–4309
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: 484–497
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: 1949–1954
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: 4149–4170
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Li, X., Yang, R., Gong, Y. et al. The Arabidopsis Mediator Complex Subunit MED19a is Involved in ABI5-mediated ABA Responses. J. Plant Biol. 61, 97–110 (2018). https://doi.org/10.1007/s12374-017-0277-7
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DOI: https://doi.org/10.1007/s12374-017-0277-7