S-locus F-Box proteins are solely responsible for S-RNase-based self-incompatibility of Petunia Pollen

Linhan Sun, Justin S. Williams, Shu Li, Lihua Wu, Wasi A. Khatri, Patrick G. Stone, Matthew D. Keebaugh, Teh Hui Kaoa

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Self-incompatibility (SI) in Petunia is regulated by a polymorphic S-locus. For each S-haplotype, the S-locus contains a pistilspecific S-RNase gene and multiple pollen-specific S-locus F-box (SLF) genes. Both gain-of-function and loss-of-function experiments have shown that S-RNase alone regulates pistil specificity in SI. Gain-of-function experiments on SLF genes suggest that the entire suite of encoded proteins constitute the pollen specificity determinant. However, clear-cut loss-offunction experiments must be performed to determine if SLF proteins are essential for SI of pollen. Here, we used CRISPR/ Cas9 to generate two frame-shift indel alleles of S2-SLF1 (SLF1 of S2-haplotype) in S2S3 plants of P. inflata and examined the effect on the SI behavior of S2 pollen. In the absence of a functional S2-SLF1, S2 pollen was either rejected by or remained compatible with pistils carrying one of eight normally compatible S-haplotypes. All results are consistent with interaction relationships between the 17 SLF proteins of S2-haplotype and these eight S-RNases that had been determined by gain-offunction experiments performed previously or in this work. Our loss-of-function results provide definitive evidence that SLF proteins are solely responsible for SI of pollen, and they reveal their diverse and complex interaction relationships with S-RNases to maintain SI while ensuring cross-compatibility.

Original languageEnglish (US)
Pages (from-to)2959-2972
Number of pages14
JournalPlant Cell
Issue number12
StatePublished - Dec 2018

All Science Journal Classification (ASJC) codes

  • Plant Science


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