title: Degradation of S-RNase in compatible pollen tubes of Solanum chacoense inferred by immunogold labeling.
abstract: The flowering plant Solanum chacoense uses an S-RNase-based self-incompatibility system in order to reject pollen that shares the same genes at the S-locus (S-haplotype) with the style (an incompatible reaction). Two different models have been advanced to explain how compatible pollen tubes are protected from the cytotoxic effects of the S-RNase, sequestration of the S-RNase in a vacuolar compartment or degradation of the S-RNase in the cytoplasm. Here, we examine the subcellular distribution of an S11-RNase 18 and 24 h post pollination (hpp) in compatible and incompatible crosses by immunogold labeling and transmission electron microscopy. We find that the S-RNase is present in the cytoplasm of both compatible and incompatible crosses by 18 hpp, but that almost all the cytoplasmic S-RNase is degraded by 24 hpp in compatible crosses. These results provide compelling evidence that S-RNases are degraded in compatible but not in incompatible pollen tubes.
authors: Institut de Recherche en Biologie Végétale (IRBV), Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke est, Montréal, QC H1X 2B2, Canada.
authors: Nicolas
authors: N
authors: Boivin
authors: Institut de Recherche en Biologie Végétale (IRBV), Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke est, Montréal, QC H1X 2B2, Canada.
authors: David
authors: D
authors: Morse
authors: Institut de Recherche en Biologie Végétale (IRBV), Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke est, Montréal, QC H1X 2B2, Canada mario.cappadocia@umontreal.ca.
authors: Mario
authors: M
authors: Cappadocia
mesh_terms: D007150:Immunohistochemistry; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D053205:Pollen Tube / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D054817:Pollination; D012260:Ribonucleases / Q000737:chemistry / Q000378:metabolism*; D032322:Solanum / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D012260:Ribonucleases; C022542:ribonuclease S
keywords: Gametophytic self-incompatibility; Pollination; S-RNase