Diverged subpopulations in tropical Urochloa (Brachiaria) forage species indicate a role for facultative apomixis and varying ploidy in their population structure and evolution.
Diverged subpopulations in tropical Urochloa (Brachiaria) forage species indicate a role for facultative apomixis and varying ploidy in their population structure and evolution.
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DOI：
10.1093/aob/mcac115
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发表时间：
2022-11-17
期刊：
影响因子：
4.2
通讯作者：
中科院分区：
文献类型：
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Urochia（syn. Brachiaria）是作为饲料原料播种的热带草属，特别是在边缘土壤中。本研究旨在阐明尾轮虫属物种的遗传多样性和种群结构，以更好地理解种群进化与倍性水平和无融合生殖发生的关系。我们探讨了111个加入的遗传多样性，从五个Urophila种用于开发商业品种。这些加入保存从野生材料收集在其原产地在非洲的中心，他们暂时代表完整的Urophila基因库中使用的育种计划。我们使用RNA测序产生了110万个单核苷酸多态性位点。我们采用遗传混合、主成分和系统发育分析来定义亚群。我们观察到三个高度分化的亚群在U。brizantha，与倍性无关：1株与U. decumbens，和两个分歧，从前者和其他物种在复杂的。我们还观察到两个亚群在U。humidicola，无关倍性;一个亚群有较少的加入，但包括唯一的特点性加入的物种。我们的研究结果也支持了美国的一个部门。在二倍体和多倍体之间，U. ruziziensis和U.马克西姆多倍体U.伏生类与多倍体U. brizantha比二倍体U. decumbens，这支持了两个多倍体群体从一个共同的四倍体祖先的分歧，并提供了倍性杂交障碍的证据。对无融合生殖多倍体U. brizantha种质构成了分化的生态型，可能在杂交育种中得到利用。在非无融合生殖的U中未观察到亚群。ruziziensis。没有发现有性的Uropla多倍体（U. brizantha，U. decumbens）或仅限于小亚群（U。湿生菌）。在Uroplata有性-无融合生殖多倍性复合体中观察到的亚群结构支持地理孤雌生殖，其中多倍体基因型利用无融合生殖的进化优势，即单亲生殖和克隆性，占据广泛的地理区域。
Urochloa (syn. Brachiaria) is a genus of tropical grasses sown as forage feedstock, particularly in marginal soils. Here we aimed to clarify the genetic diversity and population structure in Urochloa species to understand better how population evolution relates to ploidy level and occurrence of apomictic reproduction. We explored the genetic diversity of 111 accessions from the five Urochloa species used to develop commercial cultivars. These accessions were conserved from wild materials collected at their centre of origin in Africa, and they tentatively represent the complete Urochloa gene pool used in breeding programmes. We used RNA-sequencing to generate 1.1 million single nucleotide polymorphism loci. We employed genetic admixture, principal component and phylogenetic analyses to define subpopulations. We observed three highly differentiated subpopulations in U. brizantha, which were unrelated to ploidy: one intermixed with U. decumbens, and two diverged from the former and the other species in the complex. We also observed two subpopulations in U. humidicola, unrelated to ploidy; one subpopulation had fewer accessions but included the only characterized sexual accession in the species. Our results also supported a division of U. decumbens between diploids and polyploids, and no subpopulations within U. ruziziensis and U. maxima. Polyploid U. decumbens are more closely related to polyploid U. brizantha than to diploid U. decumbens, which supports the divergence of both polyploid groups from a common tetraploid ancestor and provides evidence for the hybridization barrier of ploidy. The three differentiated subpopulations of apomictic polyploid U. brizantha accessions constitute diverged ecotypes, which can probably be utilized in hybrid breeding. Subpopulations were not observed in non-apomictic U. ruziziensis. Sexual Urochloa polyploids were not found (U. brizantha, U. decumbens) or were limited to small subpopulations (U. humidicola). The subpopulation structure observed in the Urochloa sexual–apomictic multiploidy complexes supports geographical parthenogenesis, where the polyploid genotypes exploit the evolutionary advantage of apomixis, i.e. uniparental reproduction and clonality, to occupy extensive geographical areas.
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DOI：
10.4025/actasciagron.v30i4.5293
发表时间：
2008-12-01
期刊：
Acta Scientiarum. Agronomy
影响因子：
--
作者：
Ambiel, Ana Claudia;Guaberto, Luciana Machado;Machado Neto, Nelson Barbosa
通讯作者：
Machado Neto, Nelson Barbosa
影响因子：
1.9
作者：
LUTTS, S;NDIKUMANA, J;LOUANT, BP
通讯作者：
LOUANT, BP
影响因子：
1.9
作者：
Burton, WA;Ripley, VL;Salisbury, PA
通讯作者：
Salisbury, PA
影响因子：
5.8
作者：
Bradbury, Peter J.;Zhang, Zhiwu;Buckler, Edward S.
通讯作者：
Buckler, Edward S.
影响因子：
2.3
作者：
Jimena Trivino, Narda;Guillermo Perez, Juan;Worthington, Margaret
通讯作者：
Worthington, Margaret