Molecular and General Genetics MGG

, Volume 260, Issue 2–3, pp 261–268

Cloning and characterization of cDNAs encoding S-RNases from almond (Prunus dulcis): primary structural features and sequence diversity of the S-RNases in Rosaceae

  • K. Ushijima
  • H. Sassa
  • R. Tao
  • H. Yamane
  • A. M. Dandekar
  • T. M. Gradziel
  • H. Hirano
ORIGINAL PAPER

Abstract

cDNAs encoding three S-RNases of almond (Prunus dulcis), which belongs to the family Rosaceae, were cloned and sequenced. The comparison of amino acid sequences between the S-RNases of almond and those of other rosaceous species showed that the amino acid sequences of the rosaceous S-RNases are highly divergent, and intra-subfamilial similarities are higher than inter-subfamilial similarities. Twelve amino acid sequences of the rosaceous S-RNases were aligned to characterize their primary structural features. In spite of␣their high level of diversification, the rosaceous S-RNases were found to have five conserved regions, C1, C2, C3, C5, and RC4 which is Rosaceae-specific conserved region. Many variable sites fall into one region, named RHV. RHV is located at a similar position to that of the hypervariable region a (HVa) of the solanaceous S-RNases, and is assumed to be involved in recognizing S-specificity of pollen. On the other hand, the region corresponding to another solanaceous hypervariable region (HVb) was not variable in the rosaceous S-RNases. In the phylogenetic tree of the T2/S type RNase, the rosaceous S-RNase fall into two subfamily-specific groups (Amygdaloideae and Maloideae). The results of sequence comparisons and phylogenetic analysis imply that the present S-RNases of Rosaceae have diverged again relatively recently, after the divergence of subfamilies.

Key words Gametophytic self-incompatibility   T2/S type RNase   Rosaceae   Almond   Phylogenetic tree 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • K. Ushijima
    • 1
  • H. Sassa
    • 1
  • R. Tao
    • 2
  • H. Yamane
    • 2
  • A. M. Dandekar
    • 3
  • T. M. Gradziel
    • 3
  • H. Hirano
    • 1
  1. 1.Kihara Institute for Biological Research and Graduate School of Integrated Science, Yokohama City University Maioka 641-12, Totsuka-ku, Yokohama 244-0831, Japan e-mail: sassa@yokohama-cu.ac.jp Fax: +81-45-820-1901JP
  2. 2.Graduate School of Agriculture, Kyoto University Kyoto, 606-8502, JapanJP
  3. 3.Department of Pomology, University of California Davis, CA 95616, USAUS

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