TY - JOUR
T1 - Time-gated confocal microscopy reveals accumulation of exocyst subunits at the plant-pathogen interface
AU - Overdijk, Elysa J.R.
AU - Tang, Han
AU - Borst, Jan Willem
AU - Govers, Francine
AU - Ketelaar, Tijs
PY - 2020/1/23
Y1 - 2020/1/23
N2 - Polarized exocytosis is essential for plant development and defence. The exocyst, an octameric protein complex that tethers exocytotic vesicles to the plasma membrane, targets exocytosis. Upon pathogen attack, secreted materials form papillae to halt pathogen penetration. To determine if the exocyst is directly involved in targeting exocytosis to infection sites, information about its localization is instrumental. Here, we investigated exocyst subunit localization in the moss Physcomitrella patens upon pathogen attack and infection by Phytophthora capsici. Time-gated confocal microscopy was used to eliminate autofluorescence of deposited material around infection sites, allowing the visualization of the subcellular localization of exocyst subunits and of v-SNARE Vamp72A1-labelled exocytotic vesicles during infection. This showed that exocyst subunits Sec3a, Sec5b, Sec5d, and Sec6 accumulated at sites of attempted pathogen penetration. Upon pathogen invasion, the exocyst subunits accumulated on the membrane surrounding papilla-like structures and hyphal encasements. Vamp72A1-labelled vesicles were found to localize in the cytoplasm around infection sites. The re-localization of exocyst subunits to infection sites suggests that the exocyst is directly involved in facilitating polarized exocytosis during pathogenesis.
AB - Polarized exocytosis is essential for plant development and defence. The exocyst, an octameric protein complex that tethers exocytotic vesicles to the plasma membrane, targets exocytosis. Upon pathogen attack, secreted materials form papillae to halt pathogen penetration. To determine if the exocyst is directly involved in targeting exocytosis to infection sites, information about its localization is instrumental. Here, we investigated exocyst subunit localization in the moss Physcomitrella patens upon pathogen attack and infection by Phytophthora capsici. Time-gated confocal microscopy was used to eliminate autofluorescence of deposited material around infection sites, allowing the visualization of the subcellular localization of exocyst subunits and of v-SNARE Vamp72A1-labelled exocytotic vesicles during infection. This showed that exocyst subunits Sec3a, Sec5b, Sec5d, and Sec6 accumulated at sites of attempted pathogen penetration. Upon pathogen invasion, the exocyst subunits accumulated on the membrane surrounding papilla-like structures and hyphal encasements. Vamp72A1-labelled vesicles were found to localize in the cytoplasm around infection sites. The re-localization of exocyst subunits to infection sites suggests that the exocyst is directly involved in facilitating polarized exocytosis during pathogenesis.
U2 - 10.1093/jxb/erz478
DO - 10.1093/jxb/erz478
M3 - Article
VL - 71
SP - 837
EP - 849
JO - Journal of Experimental Botany
JF - Journal of Experimental Botany
SN - 0022-0957
IS - 3
ER -