SCR/SP11 encodes the male determinant of recognition specificity of self-incompatibility(SI)in Brassica species and is sporophytically expressed in the anther tapetum.Based on dominance relationships in pollen and nuc...SCR/SP11 encodes the male determinant of recognition specificity of self-incompatibility(SI)in Brassica species and is sporophytically expressed in the anther tapetum.Based on dominance relationships in pollen and nucleotide sequence similarity,the S haplotypes in Brassica have been classified as class I or class II,with class-I S haplotypes being dominant over class-II S haplotypes.Here,we revealed that S-22 in B.rapa belonging to class I is recessive to class-II S-44 and class-I S-36 in pollen,whereas it is dominant over S-60,S-40,and S-29 based on pollination tests.SCR/SP11 of S-22(SCR-22)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 SCR-22 was found to be suppressed in S-22/S-44 and S-22/S-36 heterozygotes.Normal transcription of SCR-44 was considered to be due to the transcription suppression of Smi sRNA of the S-22 haplotype and a very low methylation state of the SCR-44 promoter region in the tapetum of S-22/S-44 heterozygotes.In SCR-22,only the cytosine residue located at the–37 bp position of the promoter region was hypermethylated in the tapetum of S-22/S-44 heterozygotes,and few methylated cytosines were detected in the promoter and coding regions of SCR-22 in S-22/S-36 heterozygotes.SCR-22 was also expressed in microspores in S-22 homozygotes but not in S-22/S-44 and S-22/S-36 heterozygotes.These results suggest that a mechanism different from class-II SCR/SP11 suppression may operate for the suppression of recessive class-I SCR-22 in S heterozygotes.展开更多
基金supported in part by the Japan Society for the Promotion of Science(JSPS)Postdoctoral Fellowship for Foreign Research to C.-L.W.(P10094)the National Natural Science Foundation of China(No.31401856 to C.-L.W.)the Natural Science Foundation of Jiangsu Province(No.BK20140482 to C.-L.W.).
文摘SCR/SP11 encodes the male determinant of recognition specificity of self-incompatibility(SI)in Brassica species and is sporophytically expressed in the anther tapetum.Based on dominance relationships in pollen and nucleotide sequence similarity,the S haplotypes in Brassica have been classified as class I or class II,with class-I S haplotypes being dominant over class-II S haplotypes.Here,we revealed that S-22 in B.rapa belonging to class I is recessive to class-II S-44 and class-I S-36 in pollen,whereas it is dominant over S-60,S-40,and S-29 based on pollination tests.SCR/SP11 of S-22(SCR-22)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 SCR-22 was found to be suppressed in S-22/S-44 and S-22/S-36 heterozygotes.Normal transcription of SCR-44 was considered to be due to the transcription suppression of Smi sRNA of the S-22 haplotype and a very low methylation state of the SCR-44 promoter region in the tapetum of S-22/S-44 heterozygotes.In SCR-22,only the cytosine residue located at the–37 bp position of the promoter region was hypermethylated in the tapetum of S-22/S-44 heterozygotes,and few methylated cytosines were detected in the promoter and coding regions of SCR-22 in S-22/S-36 heterozygotes.SCR-22 was also expressed in microspores in S-22 homozygotes but not in S-22/S-44 and S-22/S-36 heterozygotes.These results suggest that a mechanism different from class-II SCR/SP11 suppression may operate for the suppression of recessive class-I SCR-22 in S heterozygotes.
