Fertilization and Uniparental Chromosome Elimination during Crosses with Maize Haploid Inducers
Fertilization and Uniparental Chromosome Elimination during Crosses with Maize Haploid Inducers
复制标题
与玉米单倍体诱导物杂交期间的受精和单亲染色体消除
DOI：
10.1104/pp.113.223982
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发表时间：
2013-10-01
期刊：
影响因子：
7.4
通讯作者：
Jin, Weiwei
中科院分区：
文献类型：
--
作者：
Zhao, Xin;Xu, Xiaowei;Jin, Weiwei
通过雄性诱导剂产生母本单倍体可以大大加速玉米（Zea mays）的育种过程。然而，单倍体形成的机制仍不清楚。在本研究中，我们构建了两个含有细胞遗传学标记B染色体或外源着丝粒组蛋白H3变体-黄色荧光蛋白载体的诱导系来研究其机制。将这两个诱导系作为传粉媒介与杂种郑单958杂交。在F1单倍体中以较低频率检测到B染色体，这是支持单倍体形成过程中选择性染色体消除发生的直接证据。我们发现大多数诱导染色体在授粉后第一周在单倍体胚胎细胞中被消除。在有缺陷的籽粒的胚乳中也检测到了染色体的逐渐消除，尽管这种现象仅发生在授粉后 15 天的某些胚乳细胞中。我们还使用 50K 单核苷酸多态性阵列对诱导子、非诱导子自交系和 42 个衍生单倍体中的单核苷酸多态性标记进行了全基因组鉴定。我们发现在单个单倍体中检测到来自父本的约 44 Mb 杂合片段，这进一步支持了父本基因渗入的发生。我们的结果表明，选择性消除单亲染色体会导致玉米中单倍体和可能有缺陷的籽粒的形成，这伴随着单倍体细胞中不寻常的父本基因渗入。
Producing maternal haploids via a male inducer can greatly accelerate maize (Zea mays) breeding process. However, the mechanism underlying haploid formation remains unclear. In this study, we constructed two inducer lines containing cytogenetic marker B chromosome or alien centromeric histone H3 variant-yellow fluorescent protein vector to investigate the mechanism. The two inducer lines as the pollinators were crossed with a hybrid ZhengDan958. B chromosomes were detected in F1 haploids at a low frequency, which was direct evidence to support the occurrence of selective chromosome elimination during haploid formation. We found that most of the inducer chromosomes were eliminated in haploid embryonic cells during the first week after pollination. The gradual elimination of chromosomes was also detected in the endosperm of defective kernels, although it occurred only in some endosperm cells as late as 15 d after pollination. We also performed a genome-wide identification of single nucleotide polymorphism markers in the inducers, noninducer inbred lines, and 42 derived haploids using a 50K single nucleotide polymorphism array. We found that an approximately 44-Mb heterozygous fragment from the male parent was detected in a single haploid, which further supported the occurrence of paternal introgression. Our results suggest that selective elimination of uniparental chromosomes leads to the formation of haploid and possible defective kernels in maize as well, which is accompanied with unusual paternal introgression in haploid cells.