Joseph C. Polacco, PhD



Professor Emeritus



BS Biochemistry Cornell University Ithaca, N.Y.
PhD Biochemistry Duke University Durham, N.C.

Research Area

Nitrogen and nitric oxide metabolism in plants.

Research Description

Emeritus Professor Joe Polacco has ‘de-emphasized’ research somewhat, but retains ties with labs in Europe and South America.  He co-advises Brazilian students at MU or as a visiting professor (e.g. Wiebke-Ströhm et al. 2012), and pursues his long-standing interest in Ni activation (Polacco et al. 2011) of plant (mainly soybean) ureases.

Ni roles in plant metabolism remain an interest (Polacco et al. 2013; Fabiano et al. 2015), esp. in economically important coffee and soybean.  However, Polacco has turned more attention to urease roles in plant defense (insecticidal, inflammatory, and fungitoxic) (Tezotto et al. 2016) and rhizosphere signaling (Medeiros-Silva et al, 2014).  Understanding defense roles was the aim of a Mizzou Advantage Undergraduate Research Team project in which Polacco, Dr. Gary Weisman (Biochemistry) and Dr. Qisheng Song (Entomology), directed a 6-member undergraduate research team to examine these properties.  Intact Helicobacter pylori urease was found to work through the P2Y2R signaling pathways stimulating intracellular Ca2+ mobilization and mitogen-activated protein kinase (MAPK) activation in cultured astrocytes.

The insecticidal effect of a specific urease sub-peptide is still being tested in Drosophila, an insect that lacks the gut cathepsins that release this peptide in urease-sensitive insects.  If Drosophila proves sensitive, it will be subjected to genetic manipulation to identify the peptide’s target and mode of action.

Notable Honors and Service

  • Fulbright Research Awards (2000, 2005)
  • International Engagement Award, Missouri International Student Council (April 2016)

Selected Publications

Strodtman KN, Stevenson SE, Waters JK, Mawhinney TP, Thelen JJ, Polacco JC, Emerich DW. (2017). The Bacteroid Periplasm in Soybean Nodules Is an Interkingdom Symbiotic Space. Mol Plant Microbe Interact. 30(12):997-1008. doi: 10.1094/MPMI-12-16-0264-R. [PubMed]

Rechenmacher C, Wiebke-Strohm B, Oliveira-Busatto LA, Polacco JC, Carlini CR, Bodanese-Zanettini MH. (2017). Effect of soybean ureases on seed germination and plant development. Genet Mol Biol. 40(1 suppl 1):209-216. doi: 10.1590/1678-4685-GMB-2016-0107. [PubMed]

de Macedo FG, Bresolin JD, Santos EF, Furlan F, Lopes da Silva WT, Polacco JC, Lavres J. (2016). Nickel Availability in Soil as Influenced by Liming and Its Role in Soybean Nitrogen Metabolism. Front Plant Sci. 7:1358. doi: 10.3389/fpls.2016.01358. eCollection 2016. [PubMed]

Fabiano CC, Tezotto T, Favarin JL, Polacco JC, Mazzafera P. (2015). Essentiality of nickel in plants: a role in plant stresses. Front Plant Sci. 6:754. doi: 10.3389/fpls.2015.00754. eCollection 2015. [PubMed]

Polacco JC, Mazzafera P, Tezotto T. (2013). Opinion: nickel and urease in plants: still many knowledge gaps. Plant Sci. 199-200:79-90. doi: 10.1016/j.plantsci.2012.10.010. Review. Erratum in: Plant Sci. 2013 May;205-206:1. [PubMed]

Polacco JC, Hyten DL, Medeiros-Silva M, Sleper DA, Bilyeu KD. (2011). Mutational analysis of the major soybean UreF paralogue involved in urease activation. J Exp Bot. 62(10):3599-608. doi: 10.1093/jxb/err054. [PubMed]