Veleba Adam, Šmarda Petr, Zedek František, Horová Lucie, Šmerda Jakub, Bureš Petr
Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, Brno, CZ 61137, Czech Republic.
Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, Brno, CZ 61137, Czech Republic
Ann Bot. 2017 Feb;119(3):409-416. doi: 10.1093/aob/mcw229. Epub 2016 Dec 26.
Studies in the carnivorous family Lentibulariaceae in the last years resulted in the discovery of the smallest plant genomes and an unusual pattern of genomic GC content evolution. However, scarcity of genomic data in other carnivorous clades still prevents a generalization of the observed patterns. Here the aim was to fill this gap by mapping genome evolution in the second largest carnivorous family, Droseraceae, where this evolution may be affected by chromosomal holokinetism in Drosera METHODS: The genome size and genomic GC content of 71 Droseraceae species were measured by flow cytometry. A dated phylogeny was constructed, and the evolution of both genomic parameters and their relationship to species climatic niches were tested using phylogeny-based statistics.
The 2C genome size of Droseraceae varied between 488 and 10 927 Mbp, and the GC content ranged between 37·1 and 44·7 %. The genome sizes and genomic GC content of carnivorous and holocentric species did not differ from those of their non-carnivorous and monocentric relatives. The genomic GC content positively correlated with genome size and annual temperature fluctuations. The genome size and chromosome numbers were inversely correlated in the Australian clade of Drosera CONCLUSIONS: Our results indicate that neither carnivory (nutrient scarcity) nor the holokinetism have a prominent effect on size and DNA base composition of Droseraceae genomes. However, the holokinetic drive seems to affect karyotype evolution in one of the major clades of Drosera Our survey confirmed that the evolution of GC content is tightly connected with the evolution of genome size and also with environmental conditions.
近年来对食虫植物狸藻科的研究发现了最小的植物基因组以及基因组GC含量进化的异常模式。然而，其他食虫分支中基因组数据的匮乏仍然阻碍了对所观察模式的普遍化。在此，目的是通过绘制第二大食虫植物科茅膏菜科的基因组进化图谱来填补这一空白，在茅膏菜科中，这种进化可能受茅膏菜属染色体全着丝粒现象的影响。方法：通过流式细胞术测量了71种茅膏菜科植物的基因组大小和基因组GC含量。构建了一个有时间标定的系统发育树，并使用基于系统发育的统计方法检验了这两个基因组参数的进化及其与物种气候生态位的关系。
茅膏菜科的2C基因组大小在488至10927Mbp之间变化，GC含量在37.1%至44.7%之间。食虫植物和全着丝粒物种的基因组大小和基因组GC含量与其非食虫和单着丝粒的亲缘物种并无差异。基因组GC含量与基因组大小和年温度波动呈正相关。在茅膏菜属的澳大利亚分支中，基因组大小与染色体数目呈负相关。结论：我们的结果表明，食虫性（营养匮乏）和全着丝粒现象对茅膏菜科基因组的大小和DNA碱基组成均无显著影响。然而，全着丝粒驱动似乎影响了茅膏菜属一个主要分支的核型进化。我们的调查证实，GC含量的进化与基因组大小的进化以及环境条件紧密相连。
