Compartmentalization of S-RNase and HT-B degradation in self-incompatible Nicotiana

Ariel Goldraij, Katsuhiko Kondo, Christopher B. Lee, C. Nathan Hancock, Mayandi Sivaguru, Sonia Vazquez-Santana, Sunran Kim, Thomas E. Phillips, Felipe Cruz-Garcia, Bruce McClure

Research output: Contribution to journalArticlepeer-review


Pollen-pistil interactions are crucial for controlling plant mating. For example, S-RNase-based self-incompatibility prevents inbreeding in diverse angiosperm species. S-RNases are thought to function as specific cytotoxins that inhibit pollen that has an S-haplotype that matches one of those in the pistil. Thus, pollen and pistil factors interact to prevent mating between closely related individuals. Other pistil factors, such as HT-B, 4936-factor and the 120 kDa glycoprotein, are also required for pollen rejection but do not contribute to S-haplotype-specificity per se. Here we show that S-RNase is taken up and sorted to a vacuolar compartment in the pollen tubes. Antibodies to the 120 kDa glycoprotein label the compartment membrane. When the pistil does not express HT-B or 4936-factor, S-RNase remains sequestered, unable to cause rejection. Similarly, in wild-type pistils, compatible pollen tubes degrade HT-B and sequester S-RNase. We suggest that S-RNase trafficking and the stability of HT-B are central to S-specific pollen rejection.

Original languageEnglish (US)
Pages (from-to)805-810
Number of pages6
Issue number7078
StatePublished - Feb 16 2006

ASJC Scopus subject areas

  • General


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