Self-compatibility in Brassica napus is caused by independent mutations in S-locus genes
Self-compatibility in Brassica napus is caused by independent mutations in S-locus genes
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DOI：
10.1111/j.1365-313x.2007.03058.x
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发表时间：
2007-05-01
期刊：
影响因子：
7.2
通讯作者：
Nishio, Takeshi
中科院分区：
文献类型：
--
作者：
Okamoto, Shunsuke;Odashima, Masashi;Nishio, Takeshi
甘蓝型油菜是一个双二倍体物种，其A基因组来自甘蓝型油菜，C基因组来自甘蓝。虽然甘蓝型油菜、甘蓝型油菜和人工合成的双二倍体与AC基因组是自交不亲和的，但甘蓝型油菜是自交亲和的。在甘蓝型油菜中鉴定出6种S基因型，其中5种含有来自1个物种的I类S单倍型，1个含有来自其他物种的II类S单倍型，并在其中3个S基因型中发现了导致自交亲和的突变。最主要的S基因(Bns-1；Bns-6)，即cv.‘Westar’具有与油菜S-47(BRS-47)相似的一级S单倍型和与甘蓝S-15(BoS-15)相似的二级S单倍型。‘Westar’的柱头排斥BRS-47和BoS-15的花粉粒，正反交亲和。在BNS-1的SP11/Scr等位基因启动子区域插入了一条约3.6kb的DNA片段，在‘Westar’中未检测到SP11/Scr的转录本。BNS-6株SP11基因组DNA与BoS-15株SP11基因组DNA核苷酸序列100%一致。在人工合成的甘蓝型油菜品系中，一个物种的I类SP11等位基因对另一个物种的II类SP11等位基因表现出显性，表明非功能显性SP11等位基因抑制了隐性SP11等位基因在‘Westar’中的表达。甘蓝型油菜中的另外两个S基因型也存在非功能性I类S单倍型，并伴有隐性BNS-6。这些观察结果表明，甘蓝型油菜的自交亲和性起源独立。
Brassica napus is an amphidiploid species with the A genome from Brassica rapa and the C genome from Brassica oleracea. Although B. rapa, B. oleracea and artificially synthesized amphidiploids with the AC genome are self-incompatible, B. napus is self-compatible. Six S genotypes were identified in B. napus, five of which had class I S haplotypes from one species and a class II S haplotype from the other species, and mutations causing self-compatibility were identified in three of these S genotypes. The most predominant S genotype (BnS-1;BnS-6), which is that of cv. 'Westar', had a class I S haplotype similar to B. rapa S-47 (BrS-47) and a class II S haplotype similar to B. oleracea S-15 (BoS-15). The stigmas of 'Westar' rejected the pollen grains of both BrS-47 and BoS-15, while reciprocal crossings were compatible. Insertion of a DNA fragment of about 3.6 kb was found in the promoter region of the SP11/SCR allele of BnS-1, and transcripts of SP11/SCR were not detected in 'Westar'. The nucleotide sequence of the SP11 genomic DNA of BnS-6 was 100% identical to that of SP11 of BoS-15. Class I SP11 alleles from one species showed dominance over class II SP11 alleles from the other species in artificially synthesized B. napus lines, suggesting that the non-functional dominant SP11 allele suppressed the expression of the recessive SP11 allele in 'Westar'. Two other S genotypes in B. napus also had non-functional class I S haplotypes together with recessive BnS-6. These observations suggest independent origins of self-compatibility in B. napus.