QUANTITATIVE VARIATION FOR APOMICTIC REPRODUCTION IN THE GENUS BOECHERA (BRASSICACEAE)
QUANTITATIVE VARIATION FOR APOMICTIC REPRODUCTION IN THE GENUS BOECHERA (BRASSICACEAE)
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DOI：
10.3732/ajb.1000188
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发表时间：
2010-10-01
影响因子：
3
通讯作者：
Sharbel, Timothy F.
中科院分区：
文献类型：
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作者：
Aliyu, Olawale M.;Schranz, M. Eric;Sharbel, Timothy F.
研究结论：有性亲缘植物无性生殖（无融合生殖）的进化是植物生物学的一大谜团。Boechera属是研究无融合生殖的理想植物，因为它与拟南芥的关系密切，并且在低倍性水平（二倍体和三倍体）下发生有性和无融合生殖物种。无融合生殖的特征在于三个组成部分：未减数的胚囊形成（无融合生殖）、不依赖受精的胚胎发生（孤雌生殖）和功能性胚乳形成（假配生殖或自主胚乳形成）。了解这些性状在物种内和物种之间的变化一直受到阻碍的费力的组织学分析所需的分析大量的samples.Methods：为了量化无融合生殖种子发育的不同组成部分的变异性，我们开发了一种高通量流式细胞术种子筛选技术来测量胚胎：胚乳倍性在来自71个二倍体和三倍体Boechera的超过22 000个单种子中进行了分析。关键结果：在Boechera物种内部和之间确定了三个相互关联的特征：（1）与无融合生殖种子形成相关的大多数性状的变异，（2）无融合生殖表达的三个水平（低、高、专性），以及（3）无减数分裂与孤雌生殖/假受精之间的相关性。结论：这里提出的数据提供了一个框架，用于选择特定的基因型与大的“组学”数据集正在收集的Boechera研究人口结构，基因流和特定性状的进化的相关性。我们推测，低水平的无减数分裂代表的祖先条件的Boechera，而高水平的无减数分裂可能已被诱导的全球基因调控变化与杂交。
Premise of the study : The evolution of asexual seed production (apomixis) from sexual relatives is a great enigma of plant biology. The genus Boechera is ideal for studying apomixis because of its close relation to Arabidopsis and the occurrence of sexual and apomictic species at low ploidy levels (diploid and triploid). Apomixis is characterized by three components: unreduced embryo-sac formation (apomeiosis), fertilization-independent embryogenesis (parthenogenesis), and functional endosperm formation (pseudogamy or autonomous endosperm formation). Understanding the variation in these traits within and between species has been hindered by the laborious histological analyses required to analyze large numbers of samples.Methods : To quantify variability for the different components of apomictic seed development, we developed a high-throughput flow cytometric seed screen technique to measure embryo : endosperm ploidy in over 22 000 single seeds derived from 71 accessions of diploid and triploid Boechera.Key results : Three interrelated features were identified within and among Boechera species: (1) variation for most traits associated with apomictic seed formation, (2) three levels of apomeiosis expression (low, high, obligate), and (3) correlations between apomeiosis and parthenogenesis/pseudogamy.Conclusions : The data presented here provide a framework for choosing specific genotypes for correlations with large "omics" data sets being collected for Boechera to study population structure, gene flow, and evolution of specific traits. We hypothesize that low levels of apomeiosis represent an ancestral condition of Boechera, whereas high apomeiosis levels may have been induced by global gene regulatory changes associated with hybridization.