RNase-based self-incompatibility: puzzled by pollen S.
Many plants have a genetically determined self-incompatibility system in which the rejection of self pollen grains is controlled by alleles of an S locus. A common feature of these S loci is that separate pollen- and style-expressed genes (pollen S and style S, respectively) determine S allele identity. The long-held view has been that pollen S and style S must be a coevolving gene pair in order for allelic recognition to be maintained as new S alleles arise. In at least three plant families, the Solanaceae, Rosaceae, and Plantaginaceae, the style S gene has long been known to encode an extracellular ribonuclease called the S-RNase. Pollen S in these families has more recently been identified and encodes an F-box protein known as either SLF or SFB. In this perspective, we describe the puzzling evolutionary relationship that exists between the SLF/SFB and S-RNase genes and show that in most cases cognate pairs of genes are not coevolving in the expected manner. Because some pollen S genes appear to have arisen much more recently than their style S cognates, we conclude that either some pollen S genes have been falsely identified or that there is a major problem with our understanding of how the S locus evolves.
Newbigin
Ed
E
School of Botany, University of Melbourne, VIC 3010, Australia. edwardjn@unimelb.edu.au
Paape
Timothy
T
Kohn
Joshua R
JR
D000483:Alleles; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism; D005298:Fertility / Q000235:genetics / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011058:Pollen / Q000235:genetics / Q000502:physiology*; D054817:Pollination / Q000235:genetics / Q000502:physiology*; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism*
D044783:F-Box Proteins; D010940:Plant Proteins; D012260:Ribonucleases; C092227:S1-RNase; C022542:ribonuclease S
Curr Opin Plant Biol. 2006 Dec;9(6):639-46
17027324
Proc Natl Acad Sci U S A. 1990 Apr;87(7):2419-23
2320564
Plant Cell. 1999 Nov;11(11):2087-97
10559436
Genetics. 2007 Dec;177(4):2171-80
17947432
Plant Cell. 2004 Nov;16(11):2840-7
15522846
Bioinformatics. 2003 Dec 12;19(18):2496-7
14668244
Genetics. 1939 Jun;24(4):538-52
17246937
Genetics. 2002 Oct;162(2):931-40
12399400
Plant Mol Biol. 2003 Nov;53(4):565-80
15010619
J Mol Evol. 2007 Aug;65(2):175-85
17713808
Genetics. 1994 Aug;137(4):1157-65
7982569
Trends Genet. 2005 Sep;21(9):500-5
16023253
Plant Cell. 2004 Mar;16(3):582-95
14973168
Plant Cell. 2005 Jan;17(1):37-51
15598801
Plant J. 2006 Jun;46(5):780-93
16709194
Plant J. 1998 Dec;16(5):591-9
10036777
Genes Cells. 2003 Mar;8(3):203-13
12622718
Am J Bot. 2005 Feb;92(2):297-315
21652407
Curr Biol. 1997 Jan 1;7(1):R34-7
9072167
J Hered. 2006 Sep-Oct;97(5):514-20
16985081
Annu Rev Plant Biol. 2005;56:467-89
15862104
Genetics. 2007 Apr;175(4):1869-81
17237509
Heredity (Edinb). 1995 Oct;75 ( Pt 4):405-15
7591834
Mol Biol Evol. 2003 Nov;20(11):1778-94
12885955
Plant Cell. 2007 Nov;19(11):3593-609
18024566
FEBS Lett. 1998 Dec 4;440(3):337-42
9872398
Plant Cell Rep. 2004 Feb;22(7):497-501
14564475
Plant Cell. 2004 Sep;16(9):2307-22
15308757
Heredity (Edinb). 2007 Nov;99(5):553-61
17700636
Plant Cell. 2006 Oct;18(10):2531-53
17028207
New Phytol. 2006;172(3):577-87
17083687
Mol Biol Evol. 2002 Jun;19(6):825-9
12032238
Plant J. 2004 Aug;39(4):573-86
15272875
Proc Natl Acad Sci U S A. 2001 Nov 6;98(23):13167-71
11698683
Bioinformatics. 1998;14(9):817-8
9918953
Nature. 2004 May 20;429(6989):302-5
15152253
Plant Mol Biol. 2002 Sep;50(1):29-42
12139007
Plant J. 2007 May;50(4):723-34
17461794
Proc Natl Acad Sci U S A. 1990 Dec;87(24):9732-5
2263623
Bioinformatics. 2003 Aug 12;19(12):1572-4
12912839
Mol Biol Evol. 2008 Apr;25(4):655-63
18209194
Plant Cell. 2003 Mar;15(3):771-81
12615948
Plant Cell. 1996 May;8(5):805-14
8672882