Wang Chun-Lei, Zhang Zhi-Ping, Oikawa Eriko, Kitashiba Hiroyasu, Nishio Takeshi
1School of Horticulture and Plant Protection, Joint International Research Laboratory of Agriculture and Agri-Product Safety, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, 48 Wenhui East Road, Yangzhou, 225009 People's Republic of China.
2Graduate School of Agricultural Science, Tohoku University, 468-1 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-0845 Japan.
Hortic Res. 2019 Feb 1;6:25. doi: 10.1038/s41438-018-0103-5. eCollection 2019.
encodes the male determinant of recognition specificity of self-incompatibility (SI) in species and is sporophytically expressed in the anther tapetum. Based on dominance relationships in pollen and nucleotide sequence similarity, the haplotypes in have been classified as class I or class II, with class-I haplotypes being dominant over class-II haplotypes. Here, we revealed that in belonging to class I is recessive to class-II and class-I in pollen, whereas it is dominant over , , and based on pollination tests. of () was sequenced, revealing that the deduced amino-acid sequence of SCR-22 has the longest C-terminal domain among the SCR/SP11 sequences. The expression of was found to be suppressed in and heterozygotes. Normal transcription of was considered to be due to the transcription suppression of sRNA of the haplotype and a very low methylation state of the promoter region in the tapetum of heterozygotes. In , only the cytosine residue located at the -37 bp position of the promoter region was hypermethylated in the tapetum of heterozygotes, and few methylated cytosines were detected in the promoter and coding regions of in heterozygotes. was also expressed in microspores in homozygotes but not in and heterozygotes. These results suggest that a mechanism different from class-II / suppression may operate for the suppression of recessive class-I in heterozygotes.
编码物种中自交不亲和性（SI）识别特异性的雄性决定因子，并在花药绒毡层中进行孢子体表达。根据花粉中的显性关系和核苷酸序列相似性，已将中的单倍型分为I类或II类，I类单倍型对II类单倍型具有显性。在这里，我们发现属于I类的在花粉中对II类和I类是隐性的，而根据授粉试验，它对、和是显性的。对（）的进行了测序，结果表明，推导的SCR - 22氨基酸序列在SCR/SP11序列中具有最长的C末端结构域。发现在和杂合子中被抑制表达。被认为正常转录是由于单倍型的sRNA转录抑制以及杂合子绒毡层中启动子区域的甲基化状态非常低。在中，仅启动子区域 - 37bp位置的胞嘧啶残基在杂合子的绒毡层中发生了高甲基化，在杂合子的启动子和编码区域中检测到的甲基化胞嘧啶很少。在纯合子的小孢子中也有表达，但在和杂合子中不表达。这些结果表明，在杂合子中，可能存在一种不同于II类/抑制的机制来抑制隐性I类。
