Self-compatibility in 'Zaohong' Japanese apricot is associated with the loss of function of pollen S genes.
While most Japanese apricot (Prunus mume Sieb. et Zucc.) cultivars display typical S-RNase-based gametophytic self-incompatibility, some self-compatible (SC) cultivars have also been identified. In this study, we confirmed SC of 'Zaohong' through replicated self-pollination tests. Cross-pollination tests showed that SC of 'Zaohong' was caused by a loss of pollen function, so we determined that the S-genotype of 'Zaohong' was S 2 S 15 . Sequence analysis of the S-haplotypes of 'Zaohong' showed no mutations which were likely to alter gene function. Furthermore, expression analysis based on RT-PCR of S-locus genes revealed no differences at the transcript level when compared with 'Xiyeqing', a self-incompatible cultivar with the same S haplotypes. In addition, except for S-locus genes, a new type of F-box gene encoding a previously uncharacterised protein with high sequence similarity (61.03-64.65 %) to Prunus SFB genes was identified. Putative structural regions of PmF-box genes have been described, corresponding to regions in PmSFB alleles, but with some sequence variations. These results suggest that SC in 'Zaohong' occurs in pollen, and that other factors outside the S-locus, including PmF-box genes, might be associated with the loss of function of pollen S genes.
College of Horticulture, Nanjing Agricultural University, No.1 Weigang, Nanjing City, 210095, Jiangsu Province, People's Republic of China.
Pei-Pei
PP
Wang
Zhi-Hong
ZH
Gao
Zhao-Jun
ZJ
Ni
Zhen
Z
Zhang
Bin-Hua
BH
Cai
D000483:Alleles; D000595:Amino Acid Sequence; D044783:F-Box Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011058:Pollen / Q000235:genetics*; D054817:Pollination / Q000235:genetics* / Q000502:physiology; D027861:Prunus / Q000145:classification / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D044783:F-Box Proteins; D010940:Plant Proteins