Pathogen Trojan horse delivers bioactive host protein to alter maize (Zea mays) anther cell behavior in situ.

5 years ago

Pathogen Trojan horse delivers bioactive host protein to alter maize (Zea mays) anther cell behavior in situ.

Virginia Walbot, Chong Teng, Ljudmilla Timofejeva, Reza Hammond, Gunther Doehlemann, Blake C Meyers, Birger Ilau, Karina Van Der Linde, Rachel L Egger

Small proteins are crucial signals during development, host defense, and physiology. Spatiotemporal restricted functions of signaling proteins remain challenging to study in planta. The several month span required to assess transgene expression, particularly in flowers, combined with the uncertainties from transgene position effects and ubiquitous or overexpression, makes monitoring of spatiotemporally restricted signaling proteins lengthy and difficult. This situation could be rectified with a transient assay in which protein deployment is controlled spatially and temporally in planta to assess protein functions, timing, and cellular targets as well as to facilitate rapid mutagenesis to define functional protein domains. In maize (Zea mays), secreted ZmMAC1 (MULTIPLE ARCHESPORIAL CELLS1) was proposed to trigger somatic niche formation during anther development by participating in a ligand-receptor module. We engineered a protein-delivery system that exploits the secretory capabilities of the corn smut fungus Ustilago maydis, to allow protein delivery to individual cells in certain cell layers at precise time points. Pathogen-supplied ZmMAC1 cell-autonomously corrected somatic cell division and differentiation defects in mutant Zmmac1-1 anthers. These results suggest that exploiting host-pathogen interactions may become a useful method for targeting host proteins to cell and tissue types to clarify cellular autonomy and to analyze steps in cell responses.

Publisher URL: http://doi.org/10.1105/tpc.17.00238

DOI: 10.1105/tpc.17.00238