Tan Xiao-Feng, Zhang Lin, Wuyun Ta-Na, Yuan De-Yi, Cao Yu-Fen, Jiang Ao-Fang, Liang Wen-Jie, Zeng Yan-Ling
Key Lab of Non-Wood Forest Product of State Forestry Administration, Central South University of Forestry and Technology, Changsha 410004, China.
Zhi Wu Sheng Li Yu Fen Zi Sheng Wu Xue Xue Bao. 2007 Feb;33(1):61-70.
Self-incompatibility (SI) is an important intraspecific reproductive barrier in flowering plants. To identify the S-alleles of Chinese pear species (Pyrus pyrifolia, P. bretschneideri, P. ussuriensis and P. sinkiangenis etc.), S-RNase-specific PCR amplification, sequence analyses and field pollination tests were performed using two cultivars 'Jingxiang' and 'Esu' of P. bretschneideri as materials. Two new S-RNase genes were identified from the two cultivars. They were 1,122 bp and 1,058 bp in length, and designated as S37-RNase (GenBank accession no. DQ839238) and S38-RNase (GenBank accession no. DQ839239). By comparison of their deduced amino acid sequences with those of S1-to S36-alleles of Oriental pear, it can be seen that both the two new S-alleles had their conserved regions C1 and C2, but their hypervariable regions (HV) were quite different from those of the others. S37 showed a higher similarity (96%) to S38 in the amino acid sequences deduced from them, whereas both of them displayed the highest similarity (98%) to S15 and the lowest (63%) to S32. The two S-alleles had introns of 786 bp and 723 bp, respectively, similar in size to that of S15 (777 bp). Finally, the S-genotypes of 'Jinxiang' and 'Esu' were unambiguously determined as S34S37 and S15S38, respectively.
自交不亲和性（SI）是开花植物中一种重要的种内生殖障碍。为了鉴定中国梨品种（白梨、沙梨、秋子梨和新疆梨等）的S等位基因，以白梨的两个品种‘京香’和‘鄂酥’为材料，进行了S-RNase特异性PCR扩增、序列分析和田间授粉试验。从这两个品种中鉴定出两个新的S-RNase基因。它们的长度分别为1122 bp和1058 bp，分别命名为S37-RNase（GenBank登录号：DQ839238）和S38-RNase（GenBank登录号：DQ839239）。通过将它们推导的氨基酸序列与东方梨的S1至S36等位基因的序列进行比较，可以看出这两个新的S等位基因都有保守区域C1和C2，但它们的高变区（HV）与其他等位基因有很大不同。S37在推导的氨基酸序列上与S38显示出较高的相似性（96%），而它们与S15的相似性最高（98%），与S32的相似性最低（63%）。这两个S等位基因分别有786 bp和723 bp的内含子，大小与S15的内含子（777 bp）相似。最后，‘金香’和‘鄂酥’的S基因型分别明确确定为S34S37和S15S38。
