The F-box protein AhSLF-S2 controls the pollen function of S-RNase-based self-incompatibility.
Recently, we have provided evidence that the polymorphic self-incompatibility (S) locus-encoded F-box (SLF) protein AhSLF-S(2) plays a role in mediating a selective S-RNase destruction during the self-incompatible response in Antirrhinum hispanicum. To investigate its role further, we first transformed a transformation-competent artificial chromosome clone (TAC26) containing both AhSLF-S(2) and AhS(2)-RNase into a self-incompatible (SI) line of Petunia hybrida. Molecular analyses showed that both genes are correctly expressed in pollen and pistil in four independent transgenic lines of petunia. Pollination tests indicated that all four lines became self-compatible because of the specific loss of the pollen function of SI. This alteration was transmitted stably into the T1 progeny. We then transformed AhSLF-S(2) cDNA under the control of a tomato (Lycopersicon esculentum) pollen-specific promoter LAT52 into the self-incompatible petunia line. Molecular studies revealed that AhSLF-S(2) is specifically expressed in pollen of five independent transgenic plants. Pollination tests showed that they also had lost the pollen function of SI. Importantly, expression of endogenous SLF or SLF-like genes was not altered in these transgenic plants. These results phenocopy a well-known phenomenon called competitive interaction whereby the presence of two different pollen S alleles within pollen leads to the breakdown of the pollen function of SI in several solanaceaous species. Furthermore, we demonstrated that AhSLF-S(2) physically interacts with PhS(3)-RNase from the P. hybrida line used for transformation. Together with the recent demonstration of PiSLF as the pollen determinant in P. inflata, these results provide direct evidence that the polymorphic SLF including AhSLF-S(2) controls the pollen function of S-RNase-based self-incompatibility.
Qiao
Hong
H
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100080, China.
Wang
Fei
F
Zhao
Lan
L
Zhou
Junli
J
Lai
Zhao
Z
Zhang
Yansheng
Y
Robbins
Timothy P
TP
Xue
Yongbiao
Y
D000595:Amino Acid Sequence / Q000235:genetics; D032161:Antirrhinum / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D044782:F-Box Motifs / Q000235:genetics*; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D018551:Solanum lycopersicum / Q000235:genetics; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D032306:Petunia / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics; D011058:Pollen / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012098:Reproduction / Q000235:genetics; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014170:Transformation, Genetic / Q000235:genetics
D010455:Peptides; D010940:Plant Proteins; D012260:Ribonucleases; C022542:ribonuclease S