Bruce A. McClure, PhD

Professor Emeritus


Contact Information

Phone 573-882-3932
Phone (Lab) 573-882-3939
Address 112 Schweitzer Hall


BS Biochemistry University of Minnesota St. Paul, Minn.
PhD Biochemistry University of Minnesota St. Paul, Minn.

Research Area

Cell-cell interactions in pollen recognition and rejection.

Research Description

Research in the McClure lab is focused on understanding how pollen pistil communication controls plant mating. We study S-RNase-based self-incompatibility in Nicotiana and interspecific pollen recognition and rejection between tomato and its wild relatives. The genus Nicotiana is useful because of its ease of experimental manipulation, and the inter- and intra-specific compatibility relationships are well known. For example, N. alatadisplays gametophytic self-incompatibility (SI). Self-pollen and pollen from closely related plants are rejected, thus maintaining hybrid vigor. N. alata also has specific mechanisms for recognizing and rejecting pollen from related species such as N. plumbaginifolia and N. tabacum. Likewise, tomato, Solanum lycopersicum (formerly Lycopersicon esculentum), also has well defined crossing relationships with its wild relatives such as SI S. habrochaities and SI S. pennellii. In addition there are many powerful genetic tools available for studies of tomato.

We use genetic and biochemical techniques to identify factors that contribute to inter- and intra-specific pollen recognition and rejection. A theme for pollen-pistil interactions is that the pistil secretes factors into the extracellular matrix that pollen tubes use as a guide to the ovary. Our challenge is to identify these factors and the pollen factors they interact with to control mating. In SI for example, the pistil produces potentially cytotoxic proteins called S-RNases that are taken up by growing pollen tubes. When pollen is rejected, S-RNase is released into the pollen tube cytoplasm and growth is inhibited. Thus, our research involves biochemical and genetic experiments to identify critical pollen and pistil proteins and cell biological experiments to determine how their cellular context contributes to their functions. By understanding the natural systems control pollination, plant breeders can design new strategies to manipulate their breeding behavior for their own purposes.

Notable Honors and Service

  • Fellow, American Association for the Advancement of Science
  • Board of Directors, Science Teachers of Missouri, 2008-2009
  • Program Director for Plant, Fungal and Microbial Development at the US National Science Foundation (2010-2012)

Selected Publications

Bedinger PA, Broz AK, Tovar-Mendez A, McClure B. (2017). Pollen-Pistil Interactions and Their Role in Mate Selection. Plant Physiol. 173(1):79-90. doi: 10.1104/pp.16.01286. Review. [PubMed]

McClure B. (2016). Reproduction: The genetic basis of heterostyly. Nat Plants. 2(12):16184. doi: 10.1038/nplants.2016.184. [PubMed]

Baek YS, Royer SM, Broz AK, Covey PA, López-Casado G, Nuñez R, Kear PJ, Bonierbale M, Orillo M, van der Knaap E, Stack SM, McClure B, Chetelat RT, Bedinger PA. (2016). Interspecific reproductive barriers between sympatric populations of wild tomato species (Solanum section Lycopersicon). Am J Bot. 103(11):1964-1978. [PubMed]

Tovar-Méndez A, Lu L, McClure B. (2017). HT proteins contribute to S-RNase-independent pollen rejection in Solanum. Plant J. 89(4):718-729. doi: 10.1111/tpj.13416. [PubMed]

Broz AK, Randle AM, Sianta SA, Tovar-Méndez A, McClure B, Bedinger PA. (2017). Mating system transitions in Solanum habrochaites impact interactions between populations and species. New Phytol. 213(1):440-454. doi: 10.1111/nph.14130. [PubMed]

Tovar-Mendez A, McClure B. (2016). Plant Reproduction: Self-Incompatibility to Go. Curr Biol. 26(3):R115-7. doi: 10.1016/j.cub.2015.12.011. [PubMed]

Kear PJ, McClure B. (2012). How did flowering plants learn to avoid blind date mistakes? Self-incompatibility in plants and comparisons with nonself rejection in the immune response. Adv Exp Med Biol. 738:108-23. doi: 10.1007/978-1-4614-1680-7_7. [PubMed]

McClure B. (2012). Plant self-incompatibility: ancient system becomes a new tool. Curr Biol. 22(3):R86-7. doi: 10.1016/j.cub.2011.12.034. Erratum in: Curr Biol. 2012 Mar 6;22(5):450. [PubMed]

McClure B, Cruz-García F, Romero C. (2011). Compatibility and incompatibility in S-RNase-based systems. Ann Bot. 108(4):647-58. doi: 10.1093/aob/mcr179. Review. [PubMed]

Kumar A, McClure B. (2010). Pollen-pistil interactions and the endomembrane system. J Exp Bot. 61(7):2001-13. doi: 10.1093/jxb/erq065. [PubMed]