Loss of pollen-S function in two self-compatible selections of Prunus avium is associated with deletion/mutation of an S haplotype-specific F-box gene.
Recently, an S haplotype-specific F-box (SFB) gene has been proposed as a candidate for the pollen-S specificity gene of RNase-mediated gametophytic self-incompatibility in Prunus (Rosaceae). We have examined two pollen-part mutant haplotypes of sweet cherry (Prunus avium). Both were found to retain the S-RNase, which determines stylar specificity, but one (S3' in JI 2434) has a deletion including the haplotype-specific SFB gene, and the other (S4' in JI 2420) has a frame-shift mutation of the haplotype-specific SFB gene, causing amino acid substitutions and premature termination of the protein. The loss or significant alteration of this highly polymorphic gene and the concomitant loss of pollen self-incompatibility function provides compelling evidence that the SFB gene encodes the pollen specificity component of self-incompatibility in Prunus. These loss-of-function mutations are inconsistent with SFB being the inactivator of non-self S-RNases and indicate the presence of a general inactivation mechanism, with SFB conferring specificity by protecting self S-RNases from inactivation.
Sonneveld
Tineke
T
Plant Science Division, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, United Kingdom.
Tobutt
Kenneth R
KR
Vaughan
Simon P
SP
Robbins
Timothy P
TP
D019943:Amino Acid Substitution / Q000235:genetics; D018389:Codon, Nonsense / Q000235:genetics; D044782:F-Box Motifs / Q000235:genetics*; D016368:Frameshift Mutation / Q000235:genetics; D017353:Gene Deletion; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D020868:Gene Silencing / Q000502:physiology; D006239:Haplotypes / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D011058:Pollen / Q000235:genetics*; D027861:Prunus / Q000235:genetics*; D012100:Reproduction, Asexual / Q000235:genetics*; D012260:Ribonucleases / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D037941:Silencer Elements, Transcriptional / Q000235:genetics
D018389:Codon, Nonsense; D012260:Ribonucleases