Washington University in St. Louis
Campus Box in Biology 1137 in Engineering 1099
One Brookings Drive
St. Louis, MO 63130-4899
Research Interests of the Gladys Levis Allen Laboratory of Plant Sensory Physiology
Since "retirement", my research in the Gladys Levis Allen Laboratory of Plant Sensory Physiology - see laboratory web page - has built on earlier interests in mechanosensing and responses by joining with faculty in the Engineering School to share their diverse electromechanical modeling and analytical capabilities.
The first publications from these new collaborations provides a first-ever look at a lysine-rich arabinogalactan protein by atomic force microscopy (e.g. 1st picture). We have high-resolution images of protein situation in various cell types (2nd figure). We will report a biological model for the function of the protein in growth, control of stomata, and protection during drought. Coupled with that is an electromechanical model for achieving protein distributions.
Recently submitted is a demonstration that the hairs on an arabidopsis seedling shoot, shaped like antennae (4th figure) are elaborate mechanosensors that can focus force toward a skirt of cells at its base, buckle, and press against them to initiate oscillations of Ca2+ there. Finite element analysis shows that the trichome wall has thickened and tapered to promote such activity (3rd figure). Rapid elevations of cell wall pH are also seen. Finite element analysis shows that the trichome wall has thickened and tapered to promote such activity (4th figure). The wall of the trichome itself undergoes four localized mechanoresponsive shifts of pH. We propose that this wall is the most elaborate ever described (e.g. 5th figure).
Pickard BG (2013) Arabinogalactan proteins--becoming less mysterious. New Phytologist : 3-5.doi:10.1093/aob/mcu172
Zhou LH, Weizbauer RA, Singamaneni S, Xu F, Genin GM, Pickard BG. (2014) Structures formed by a cell membrane-associated arabinogalactan protein on graphite or mica alone and with Yariv phenylglycosides. Annals of Botany; Part of a Special Issue on Plant Cell Walls : 1-13.doi:10.1093/aob/mcu172
Zhou LH, Liu SB, Wang PF, Lu TJ, Xu F, Genin GM, Pickard BG. (2016) The arabidopsis trichome is an active mechanosensory switch. Plant Cell & Environment, doi: 10.1111/pce.12728. (pdf).
Liu S, Weizbauer RA, Zhou LH, Erhardt DW, Xu F, Genin GM, Pickard BG (in manuscript) Biological and electromechanical models for formations and functions of a perimembrane arabinogalactan-protein in a seedling shoot.