背景:BaoliaH.W.Kung&G.L.Chu是仅在迭部县已知的单型属,甘肃省,中国。它的系统立场是矛盾的,其形态解剖学特征与所有其他藜科不同。最近的研究将Baolia视为Corispermoideae的姐妹组。因此,我们对该物种的叶绿体基因组进行了测序和比较,并根据叶绿体基因组和标记序列解析了其系统发育位置。
结果:我们对来自两个Baoliabracteata种群和两个Corispermum物种的16个样品的18个叶绿体基因组进行了测序。Baolia的这些基因组大小从152,499到152,508bp不等。简单序列重复(SSR)主要位于Baolia叶绿体基因组的LSC区域,它们中的大多数由单核苷酸A/T重复序列组成。值得注意的是,两个种群之间的SSR类型和数量存在差异。我们的系统发育分析,基于来自33个物种的完整叶绿体基因组和三个标记的组合(ITS,rbcL,和matK)来自91个物种,揭示了Baolia和Corispermoideae(Agriophyllum,Anthochlamys,和Corispermum)形成了支撑良好的进化枝和Acroglochin的姐妹。根据我们的分子测年结果,Acroglochin之间的重大分歧事件,宝莉亚,Corispernae发生在中始新世,大约44.49Mya.祖先状态重建分析表明,Baolia表现出与核心Corispermoideae特征中发现的共生状态,包括果皮和种皮。
结论:比较B.bracteata的叶绿体基因组与11种典型的Chenopodioideae和Corispermoideae的叶绿体基因组,我们观察到了一个很高的整体相似性和一个值得注意的大约3,100bp的倒置案例。仅在两个Atriplex和四个Chenopodium物种中的DNA片段。我们建议应在更广泛的意义上考虑Corispermoideae,它包括Corispermeae(核心Corispermoideae:Agriophylum,Anthochlamys,和Corispermum),以及两个新的单型部落,Acrosoglochinae(Acroglochin)和Baolieae(Baolia)。
BACKGROUND: Baolia H.W.Kung & G.L.Chu is a monotypic genus only known in Diebu County, Gansu Province, China. Its systematic position is contradictory, and its morphoanatomical characters deviate from all other Chenopodiaceae. Recent study has regarded Baolia as a sister group to Corispermoideae. We therefore sequenced and compared the chloroplast genomes of this species, and resolved its phylogenetic position based on both chloroplast genomes and marker sequences.
RESULTS: We sequenced 18 chloroplast genomes of 16 samples from two populations of Baolia bracteata and two Corispermum species. These genomes of Baolia ranged in size from 152,499 to 152,508 bp. Simple sequence repeats (SSRs) were primarily located in the LSC region of Baolia chloroplast genomes, and most of them consisted of single nucleotide A/T repeat sequences. Notably, there were differences in the types and numbers of SSRs between the two populations of B. bracteata. Our phylogenetic analysis, based on both complete chloroplast genomes from 33 species and a combination of three markers (ITS, rbcL, and matK) from 91 species, revealed that Baolia and Corispermoideae (Agriophyllum, Anthochlamys, and Corispermum) form a well-supported clade and sister to Acroglochin. According to our molecular dating results, a major divergence event between Acroglochin, Baolia, and Corispermeae occurred during the Middle Eocene, approximately 44.49 mya. Ancestral state reconstruction analysis showed that Baolia exhibited symplesiomorphies with those found in core Corispermoideae characteristics including pericarp and seed coat.
CONCLUSIONS: Comparing the chloroplast genomes of B. bracteata with those of eleven typical Chenopodioideae and Corispermoideae species, we observed a high overall similarity and a one notable noteworthy case of inversion of approximately 3,100 bp. of DNA segments only in two Atriplex and four Chenopodium species. We suggest that Corispermoideae should be considered in a broader sense, it includes Corispermeae (core Corispermoideae: Agriophyllum, Anthochlamys, and Corispermum), as well as two new monotypic tribes, Acroglochineae (Acroglochin) and Baolieae (Baolia).