Taxonomy and Biogeography of Apomixis in Angiosperms and Associated Biodiversity Characteristics.
Taxonomy and Biogeography of Apomixis in Angiosperms and Associated Biodiversity Characteristics.
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DOI：
10.1080/07352689.2014.898488
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发表时间：
2014-09-03
影响因子：
6.9
通讯作者：
Hörandl E
中科院分区：
文献类型：
--
作者：
Hojsgaard D;Klatt S;Baier R;Carman JG;Hörandl E
被子植物的无融合生殖是种子的无性繁殖。它对被子植物进化和生物多样性的重要性一直难以评估，主要是因为分类文献不足。因此，我们收集了文献报道被子植物无融合生殖的发生，并将信息转移到互联网数据库（www.apomixis.uni-goettingen.de）。然后，我们寻找无融合生殖的发生和公认的措施的分类多样性和地理学之间的相关性。无融合生殖被认为是分类学上广泛的，没有明确的倾向，以特定的群体，并发生在所有分类水平的性。不定胚发生最多（148属），其次为无孢子生殖（110属）和倍数孢子生殖（68属）。所有这三种形式都是遗传分散的，但这种分散与生物多样性的措施密切相关。在无融合生殖的目和科中，无融合生殖的属数与总属数呈正相关。一般来说，菊科、禾本科和兰科的含无融合生殖的目、科和亚科较大，即，它们所含的科或属比不含无融合生殖的目、科或亚科多。此外，许多无融合生殖的属被发现是高度世界性的。在这方面，62%的人居住在多个地理区域。从热带到北极，含有孢子体或配子体无融合生殖体的属的数量减少，这一趋势与一般的生物多样性相似。虽然被子植物似乎倾向于从有性生殖转变为无融合生殖，但也有证据表明有性生殖的逆转。这种逆转可能是由伴随杂交、多倍性或其他细胞遗传学改变的遗传或表观遗传不稳定事件引起的。由于植物内遗传和基因组异质性的增加，在种和属水平上的范围扩展和多样化可能会在性逆转后更快地发生。从属到目的高度多样性和地理上广泛的分类群之间的显着丰富的无融合生殖体的表示，支持这一结论。
Apomixis in angiosperms is asexual reproduction from seed. Its importance to angiospermous evolution and biodiversity has been difficult to assess mainly because of insufficient taxonomic documentation. Thus, we assembled literature reporting apomixis occurrences among angiosperms and transferred the information to an internet database (http://www.apomixis.uni-goettingen.de). We then searched for correlations between apomixis occurrences and well-established measures of taxonomic diversity and biogeography. Apomixis was found to be taxonomically widespread with no clear tendency to specific groups and to occur with sexuality at all taxonomic levels. Adventitious embryony was the most frequent form (148 genera) followed by apospory (110) and diplospory (68). All three forms are phylogenetically scattered, but this scattering is strongly associated with measures of biodiversity. Across apomictic-containing orders and families, numbers of apomict-containing genera were positively correlated with total numbers of genera. In general, apomict-containing orders, families, and subfamilies of Asteraceae, Poaceae, and Orchidaceae were larger, i.e., they possessed more families or genera, than non-apomict-containing orders, families or subfamilies. Furthermore, many apomict-containing genera were found to be highly cosmopolitan. In this respect, 62% occupy multiple geographic zones. Numbers of genera containing sporophytic or gametophytic apomicts decreased from the tropics to the arctic, a trend that parallels general biodiversity. While angiosperms appear to be predisposed to shift from sex to apomixis, there is also evidence of reversions to sexuality. Such reversions may result from genetic or epigenetic destabilization events accompanying hybridization, polyploidy, or other cytogenetic alterations. Because of increased within-plant genetic and genomic heterogeneity, range expansions and diversifications at the species and genus levels may occur more rapidly upon reversion to sexuality. The significantly-enriched representations of apomicts among highly diverse and geographically-extensive taxa, from genera to orders, support this conclusion.