Identification and functional analysis of pistil self-incompatibility factor HT-B of petunia

Alejandro Raul Puerta, Koichiro Ushijima, Takato Koba, Hidenori Sassa

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


Gametophytic self-incompatibility (GSI) in Solanaceae, Rosaceae, and Plantaginaceae is controlled by a multiallelic S-locus. The specificities of pistil and pollen are controlled by separate S-locus genes, S-RNase and SLF/SFB, respectively. Although the S-specificity is determined by the S-locus genes, factors located outside the S-locus are also required for expression of GSI. HT-B is one of the pistil non-S-factors identified in Nicotiana and Solanum, and encodes a small asparagine/aspartate-rich extracellular protein with unknown biochemical function. Here, HT-B was cloned from Petunia and characterized. The structural features and expression pattern of Petunia HT-B were very similar to those of Nicotiana and Solanum. Unlike other solanaceous species, expression of HT-B was also observed in self-compatible Petunia species. RNA interference (RNAi)-mediated suppression of Petunia HT-B resulted in partial breakdown of GSI. Quantitative analysis of the HT-B mRNA accumulation in the transgenics showed that a 100-fold reduction is not sufficient and a >1000-fold reduction is required to achieve partial breakdown of GSI.

Original languageEnglish
Pages (from-to)1309-1318
Number of pages10
JournalJournal of experimental botany
Issue number4
Publication statusPublished - Mar 2009


  • HT-B
  • Petunia inflata
  • Pistil
  • RNAi
  • Self-incompatibility

ASJC Scopus subject areas

  • Physiology
  • Plant Science


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