J Integr Plant Biol. ›› 2013, Vol. 55 ›› Issue (5): 443-452.DOI: 10.1111/jipb.12026

• Original Article • Previous Articles     Next Articles

Molecular Characterization and Expression Analysis of S1 self-incompatibility Locus-linked Pollen 3.15 Gene in Citrus Reticulata

Hong-Xia Miao1, Zi-Xing Ye1,2, Yong-Hua Qin1,2* and Gui-Bing Hu1,2,3*   

  1. 1College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
    2Key Laboratory of Biology and Genetic Improvement of Horticultural Crops South China, Ministry of Agriculture, China
    3State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China
  • Received:2012-10-08 Accepted:2012-12-06 Published:2013-04-03
  • About author:**Corresponding author Tel.: +86 20 8528 6905; Fax: +86 20 8528 2107; E-mail: qinyh@scau.edu.cn and guibing@scau.edu.cn


Gametophytic self-incompatibility (GSI) is controlled by a highly polymorphic locus called the S-locus, which is an important factor that can result in seedless fruit in Citrus. The S1 self-incompatibility locus-linked pollen 3.15 gene (S1-3.15) belongs to a type of S locus gene. The role of S1-3.15 in the SI reaction of Citrus has not yet been reported. In this study, full-length sequences of cDNA and DNA encoding the S1-3.15 gene, referred to as CrS1-3.15, were isolated from ‘Wuzishatangju’ (Self-incompatibility, SI) and ‘Shatangju’ (Self-compatibility, SC). The predicted amino acid sequences of CrS1-3.15 between ‘Wuzishatangju’ and ‘Shatangju’ differ by only three amino acids. Compared to ‘Wuzishatangju’, three bases were substituted in the genomic DNA of CrS1-3.15 from ‘Shatangju’. Southern blot results showed that one copy of CrS1-3.15 existed in the genomic DNA of both ‘Wuzishatangju’ and ‘Shatangju’. The expression level of the CrS1-3.15 gene in the ovaries of ‘Shatangju’ was approximately 60-fold higher than that in the ovaries of ‘Wuzishatangju’. When ‘Wuzishatangju’ was cross-pollinated, the expression of CrS1-3.15 was upregulated in the ovaries at 3 d, and the highest expression levels were detected in the ovaries at 6 d after cross-pollination of ‘Wuzishatangju’ × ‘Shatangju’. To obtain the CrS1-3.15 protein, the full-length cDNA of CrS1-3.15 genes from ‘Wuzishatangju’ and ‘Shatangju’ was successfully expressed in Pichia pastoris. Pollen germination frequency of ‘Wuzishatangju’ was inhibited significantly with increasing CrS1-3.15 protein concentrations from SI ‘Wuzishatangju’.

Miao HX, Ye ZX, Qin YH, Hu GB (2013) Molecular characterization and expression analysis of S1 self-incompatibility locus-linked pollen 3.15 Gene in Citrus reticulata. J. Integr. Plant Biol. 55(5), 443–452.

Key words: Citrus reticulata, self-incompatibility, self-compatibility, S1 self-incompatibility locus-linked pollen 3.15 gene, expression analysis, pollen germination

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