Dataset Information

What is Atraphaxis L. (Polygonaceae, Polygoneae): cryptic taxa and resolved taxonomic complexity instead of the formal lumping and the lack of morphological synapomorphies.

ABSTRACT:

Background

The recently proposed recircumscription of the genus Atraphaxis (incl. Atraphaxis section Ovczinnikovia O.V. Yurtseva ex. S. Tavakkoli and Polygonum sect. Spinescentia Boissier (=A. sect. Polygonoides S. Tavakkoli, Kaz. Osaloo & Mozaff.) makes this genus fairly heterogeneous and therefore almost undefinable based on morphology. A critical comprehensive reappraisal of the group is necessary.

Methods

Using the DNA sequence data (ITS1&2 regions of nrDNA and combined trnL intron + trnL-F IGS and rpl32-trnL((UAG)) IGS regions of plastid genome), Maximum Likelihood (ML) and Bayesian analyses (BI) were applied for phylogenetic reconstructions of the tribe Polygoneae with special attention to Atraphaxis, and related taxa. Maximum parsimony reconstructions of the evolution of perianth morphology and sporoderm ornamentation in the tribe Polygoneae were also performed. Life history, morphology of shoots, leaf blades, ocreas, perianth and achene morphology, ultrasculpture of achene surface, and pollen morphology were compared, and SEM and LM images were provided.

Principal findings

The genera Atraphaxis and Polygonum were found to be widely polyphyletic. The rarest and morphologically remarkable endemic of Tian-Shan and Pamir Atraphaxis ovczinnikovii (Atraphaxis sect. Ovczinnikovia O.V. Yurtseva ex. S. Tavakkoli) was confirmed to be a sister of the clade (Atraphaxis + Polygonum sect. Spinescentia) in plastid topology. The genus Bactria (=Atraphaxis sect. Ovczinnikovia), which circumscribes two species, is newly established as a result of this analyses. Morphological data confirm the originality of the taxon.

Discussion

We are arguing for a narrow delimitation of Atraphaxis with petalloid segments and striato-perforate sporoderm ornamentation as morphological synapomorphies. The recently proposed inclusion of Polygonum sect. Spinescentia in Atraphaxis is fairly questionable from a morphological standpoint. The rank of Polygonum sect. Spinescentia requires further clarification. The generic composition of the tribe Polygoneae also requires future reappraisals.

SUBMITTER: Yurtseva OV

PROVIDER: S-EPMC4860328 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Publications

What is Atraphaxis L. (Polygonaceae, Polygoneae): cryptic taxa and resolved taxonomic complexity instead of the formal lumping and the lack of morphological synapomorphies.

Yurtseva Olga V OV Kuznetsova Oxana I OI Mavrodieva Maria E ME Mavrodiev Evgeny V EV

PeerJ 20160503

<h4>Background</h4>The recently proposed recircumscription of the genus Atraphaxis (incl. Atraphaxis section Ovczinnikovia O.V. Yurtseva ex. S. Tavakkoli and Polygonum sect. Spinescentia Boissier (=A. sect. Polygonoides S. Tavakkoli, Kaz. Osaloo & Mozaff.) makes this genus fairly heterogeneous and therefore almost undefinable based on morphology. A critical comprehensive reappraisal of the group is necessary.<h4>Methods</h4>Using the DNA sequence data (ITS1&2 regions of nrDNA and combined trnL i ...[more]

PMID: 27168986

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Project description:BackgroundFagopyrum (Polygonaceae) is a small plant lineage comprised of more than fifteen economically and medicinally important species. However, the phylogenetic relationships of the genus are not well explored, and the characteristics of Fagopyrum chloroplast genomes (plastomes) remain poorly understood so far. It restricts the comprehension of species diversity in Fagopyrum. Therefore, a comparative plastome analysis and comprehensive phylogenomic analyses are required to reveal the taxonomic relationship among species of Fagopyrum.ResultsIn the current study, 12 plastomes were sequenced and assembled from eight species and two varieties of Fagopyrum. In the comparative analysis and phylogenetic analysis, eight previously published plastomes of Fagopyrum were also included. A total of 49 plastomes of other genera in Polygonaceae were retrieved from GenBank and used for comparative analysis with Fagopyrum. The variation of the Fagopyrum plastomes is mainly reflected in the size and boundaries of inverted repeat/single copy (IR/SC) regions. Fagopyrum is a relatively basal taxon in the phylogenomic framework of Polygonaceae comprising a relatively smaller plastome size (158,768-159,985 bp) than another genus of Polygonaceae (158,851-170,232 bp). A few genera of Polygonaceae have nested distribution of the IR/SC boundary variations. Although most species of Fagopyrum show the same IRb/SC boundary with species of Polygonaceae, only a few species show different IRa/SC boundaries. The phylogenomic analyses of Fagopyrum supported the cymosum and urophyllum groups and resolved the systematic position of subclades within the urophyllum group. Moreover, the repeat sequence types and numbers were found different between groups of Fagopyrum. The plastome sequence identity showed significant differences between intra-group and inter-group.ConclusionsThe deletions of intergenic regions cause a short length of Fagopyrum plastomes, which may be the main reason for plastome size diversity in Polygonaceae species. The phylogenomic reconstruction combined with the characteristics comparison of plastomes supports grouping within Fagopyrum. The outcome of these genome resources may facilitate the taxonomy, germplasm resources identification as well as plant breeding of Fagopyrum.

Dataset Information

What is Atraphaxis L. (Polygonaceae, Polygoneae): cryptic taxa and resolved taxonomic complexity instead of the formal lumping and the lack of morphological synapomorphies.

Background

Methods

Principal findings

Discussion

Publications

What is Atraphaxis L. (Polygonaceae, Polygoneae): cryptic taxa and resolved taxonomic complexity instead of the formal lumping and the lack of morphological synapomorphies.

Similar Datasets

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