Sequence Characterization and Spatiotemporal Expression Patterns of PbS 26 - RNase Gene in Chinese White Pear (Pyrus bretschneideri)‎

Abstract EN

Many flowering plants exhibit an important intraspecific reproductive barrier phenomenon, that is, self-incompatibility (SI), in which S-RNase genes play a significant role.

To clarify the specific function of S-RNase genes in Chinese pears, the full length cDNA of PbS 26 - RNase was isolated by rapid amplification of cDNA ends (RACE) technology from Chinese white pear (Pyrus bretschneideri) cultivar “Hongpisu.” The cDNA sequence for PbS 26 - RNase was deposited in GenBank under accession number EU081888.

At the amino acid level, the PbS 26 - RNase displayed the highest similarity (96.9%) with PcSa-RNase of P.

communis, and only seven amino acid differences were present in the two S-RNases.

Phylogenetic analysis of rosaceous S-RNases indicated that the PbS 26 - RNase clustered with maloideous S-RNases, forming a subfamily-specific not a species-specific group.

The PbS 26 - RNase gene was specifically expressed in the style but not other tissues/organs.

The expression level of the PbS 26 - RNase gene rapidly increased at bell balloon stage (BBS), and then it dropped after pollination.

However, the abundance of the PbS 26 - RNase gene transcript in the style was greater after cross-pollination than after self-pollination.

In addition, a method for rapidly detecting the PbS 26 - RNase gene was developed via allele-specific primers design.

The present study could provide a scientific basis for fully clarifying the mechanism of pear SI at the molecular level.