Erin L. Connolly, Ph.D.

Erin L. Connolly, Ph.D.

  • Professor and Department Head of Plant Science
119 Tyson Building
University Park, PA 16802

Areas of Expertise

  • Plant mineral nutrition
  • Micronutrient transport
  • Molecular mechanisms of iron transport


  • Ph.D., Genetics, University of California, Davis, 1997
  • B.A., Biology, Dartmouth College, 1990

Current estimates indicate that ~3 billion people suffer from iron deficiency and plant foods serve as the principal source of iron for most people. In addition, ~30% of the world's soils are considered iron-limiting for plant growth. Improving iron uptake and partitioning in plants could therefore have dramatic effects on plant and human health. Research in the Connolly Lab focuses on the molecular mechanisms of micronutrient uptake and trafficking in plants. We are particularly interested in the mechanisms that underlie the delivery of iron to mitochondria and chloroplasts. In addition, we have a long-term goal of elucidating the mechanisms that function to maintain iron homeostasis in plants. 

Selected Publications

Poudel, P., Connolly, E.L., Kwasniewski, M., Lambert, J.D., Di Gioia, F. (2024). Zinc biofortification via fertigation using alternative zinc sources and concentration levels in pea, radish, and sunflower microgreens. Scientia Horticulturae 331:113098.

Poudel, P., Di Gioia, F., Lambert, J.D., Connolly, E.L. (2023). Zinc biofortification through seed nutri-priming using alternative zinc sources and concentration levels in pea and sunflower microgreens. Front. Plant Sci. 14:1177844. doi: 10.3389/fpls.2023.1177844

Brenton Z.W., Juengst B.T., Cooper E.A., Myers M.T., Jordan K.E., Dale S.M., Glaubitz J.C., Wang X., Boyles R.E., Connolly E.L., Kresovich S. (2020). Species-Specific Duplication Event Associated with Elevated Levels of Nonstructural Carbohydrates in Sorghum bicolor.

Cheng N, Yu H, Rao X, Park S, Connolly EL, Hirschi KD, Nakata PA. (2020). Alteration of iron responsive gene expression in Arabidopsis glutaredoxin S17 loss of function plants with or without iron stress.  Plant Signal Behav. (2020).15(6):1758455. doi: 10.1080/15592324.2020.1758455.

Jain A., Dashner Z.S. and Connolly E.L. (2019). Mitochondrial Iron Transporters (MIT1 and MIT2) Are Essential for Iron Homeostasis and Embryogenesis in Arabidopsis thaliana. Front. Plant Sci. 10:1449. doi: 10.3389/fpls.2019.01449

Jeong J., Merkovich A., Clyne M. and Connolly E.L. (2017). Directing iron transport in dicots: regulation of iron acquisition and translocation. Curr. Opin. Plant Biol. 39:106-113.

Yu H., Yang J., Shi Y., Donelson J., Thompson S.M., Sprague S., Roshan T., Wang D.L., Liu J., Park S., Nakata P.A., Connolly E.L., Hirschi K.D., Grusak M.A. and Cheng N. (2017). Arabidopsis Glutaredoxin S17 Contributes to Vegetative Growth, Mineral Accumulation, and Redox Balance during Iron Deficiency. Front Plant Sci. 8:1045.

Shakoor, N. Ziegler, G., Dilkes, B., Brenton, Z., Boyles, R., Connolly, E.L., Kresovich, S. and Baxter, I. (2016). Integration of experiments across diverse environments identifies the genetic determinants of variants in Sorghum bicolor seed element composition. Plant Physiology 170(4): 1989-98.

Jain, A, Wilson, G.T. and Connolly, E.L. (2014) The diverse roles of FRO family metalloreductases in iron and copper homeostasis, Frontiers in Plant Science. 5:100.

Jain, A. and Connolly E.L. (2013). Mitochondrial Iron Transport and Homeostasis in Plants. Frontiers in Plant Science. 4: 348.

Wilson G.T. and Connolly E.L. (2013). Running a little late: chloroplast Fe status and the circadian clock. EMBO J. 32(4): 490-2

Bernal, M., Casero, D., Singh, V., Wilson, G.T., Grande, A., Yang, H., Dodani, S.C., Pellegrini, M. Connolly, E.L., Huijser, P., Merchant, S. and Kramer, U. (2012). Transcriptome sequencing identifies SPL7-regulated Cu acquisition genes FRO4/FRO5 and the Cu dependence of Fe homeostasis in Arabidopsis. The Plant Cell. 24: 738-761.

Shanmugam, V., Lo, J.-C., Wu, C.-L., Wang, S.-L., Lai, C.-C., Connolly, E.L., Huang, J.-L. and Yeh, K.C. (2011) Differential expression and regulation of iron regulated metal transporters in Arabidopsis halleri and Arabidopsis thaliana – the role in Zn tolerance. New Phytologist 190 (1): 125-137;

Jeong, J. and Connolly, E.L. (2009) Iron uptake mechanisms in plants: Functions of the FRO family of ferric reductases. Plant Science. 176: 709-714;

Einset J. and Connolly, E.L. (2009). Glycine betaine enhances extracellular processes blocking ROS signaling during stress. Plant Signaling and Behavior. 4(3): 197-199

Kerkeb, L., Mukherjee, I., Chatterjee, I., Lahner, B., Salt, D.E. and Connolly, E.L. (2008) Iron-induced turnover of the IRT1 metal transporter requires lysine residues. Plant Physiol. 146(4): 1964-1973

Jeong, J., Cohu, C., Kerkeb, L., Pilon, M., Connolly, E.L., and Guerinot, M.L. (2008) Chloroplast Fe(III) Chelate Reductase Activity is Essential for Seedling Viability under Iron Limiting Conditions. Proc. Natl. Acad Sci USA 105(30): 10619-10624

Connolly, E.L. (2008) Raising the bar for biofortification: Enhanced levels of bioavailable calcium in carrots. Invited Research Focus. Trends in Biotechnol.  26(8): 401-403

Einset J., Winge P., Bones A.M., Connolly E.L. (2008) The FRO2 ferric reductase is required for glycine betaine's effect on chilling tolerance in Arabidopsis root. Physiol. Plant. 134(2): 334-341

Walker E. and Connolly, E.L. (2008) Time to pump iron: Iron-deficiency signaling mechanisms of higher plants. Current Opinion in Plant Biology 11(5): 530-535

Einset, J., Nielsen, E., Connolly, E.L., Bones, A., Sparstad, T., Winge, P., Zhu, J.-K. (2007). Membrane-trafficking RabA4c involved in the effect of glycine betaine on recovery from chilling stress in Arabidopsis. Physiol. Plant. 130(4): 511-518.

Ciftci-Yilmaz S., Morsy M.R., Song L., Coutu A., Krizek B.A., Lewis M.W., Warren D., Cushman J., Connolly E.L., Mittler R. (2007). The EAR-motif of the Cys2/His2-type zinc finger protein Zat7 plays a key role in the defense response of Arabidopsis to salinity stress. JBC 282(12): 9260-9268

Mukherjee, I., Campbell, N.H., Ash, J.S. and Connolly, E.L. (2006) Expression profiling of the ferric chelate reductase (FRO) Gene Family reveals differential regulation by iron and copper. Planta 223:1178-1190

Durrett. T.P. Connolly, E.L. and Rogers, E.E. (2006). Arabidopsis cpFtsY mutants exhibit pleiotropic defects including an inability to increase iron deficiency-inducible root Fe(III) chelate reductase activity.  The Plant Journal 47(3): 467

Connolly, E.L. Campbell, N., Grotz, N., Prichard, C., and Guerinot, M.L. (2003). Overexpression of the FRO2 ferric chelate reductase confers tolerance to growth on low iron and uncovers post-transcriptional control. Plant Physiol. 133:1102-1110.

Connolly, E.L. Fett, J. and Guerinot, M.L. (2002) Expression of the IRT1 metal transporter is controlled by metals at the levels of transcript and protein accumulation. The Plant Cell 14(6): 1347-1357

Connolly, E.L. and Guerinot, M.L. (2002). Iron stress in Arabidopsis- is Genomics Revealing? Genome Biology. 3(8): reviews1024.1-1024.4.

Robinson, N.J., Proctor, C.M., Connolly, E.L. and Guerinot, M.L. (1999) A ferric-chelate reductase for iron uptake from soils. Nature 397: 694-697

Grotz, N., Fox, T., Connolly, E., Park, W., Guerinot, M.L. and Eide, D. (1998).  Identification of a family of zinc transporter genes from Arabidopsis thaliana that respond to zinc deficiency.  Proc. Natl. Acad Sci USA 95(12):7220-7224.