Phylogeny of Cassieae based on seed morphological and ITS evidence

The Cassieae tribe, comprising economically significant species, is understudied in terms of phylogenetics within China. This study aimed to elucidate the taxonomic status and systematic relationships among Cassieae species by integrating seed coat micro-morphological characteristics with molecular...

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Main Authors: Jing Cai, Chuang Yang, Leyang Wang, Jiaqing He, Qiang Wang
Format: Article
Language:English
Published: PeerJ Inc. 2025-03-01
Series:PeerJ
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Online Access:https://peerj.com/articles/18947.pdf
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author Jing Cai
Chuang Yang
Leyang Wang
Jiaqing He
Qiang Wang
author_facet Jing Cai
Chuang Yang
Leyang Wang
Jiaqing He
Qiang Wang
author_sort Jing Cai
collection DOAJ
description The Cassieae tribe, comprising economically significant species, is understudied in terms of phylogenetics within China. This study aimed to elucidate the taxonomic status and systematic relationships among Cassieae species by integrating seed coat micro-morphological characteristics with molecular data from the internal transcribed spacer (ITS) region of nuclear ribosomal DNA. (1) The results indicate that the tribe is classified into seven distinct clades; Clade V consists of Chamaecrista, which is characterized by primarily monosymmetric flowers with occasional asymmetry, the presence of extrafloral nectaries (EFNs), five or ten stamens, and pods that dehisce elastically. Clade VI is associated with Senna, which displays polysymmetric or monosymmetric flowers, uniformly ten stamens or occasionally three staminodes, variable presence of EFNs, and predominantly indehiscent pods, with rare instances of slit dehiscence. Clade VII is characterized by the presence of Cassia, which exhibits polysymmetric flowers, consistently ten stamens—three of which are elongated and curved, typically exceeding the length of the petals—and indehiscent pods. (2) The monophyly of Cassia and Senna was strongly supported, with Cassia grouping closely with Senna, but distantly from Chamaecrista. (3) It is noteworthy that Senna occidentail and Senna sophera are confirmed as sister taxa, while Senna corymbosa and S. bicapsularis are confirmed as sister taxa. By integrating molecular biology and morphological taxonomy, this research enhances our comprehension of the phylogenetic relationships and evolutionary history within the Cassieae tribe in China.
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spelling doaj-art-eebd9c86e9574f5cbf04db12af0faa712025-08-20T02:50:59ZengPeerJ Inc.PeerJ2167-83592025-03-0113e1894710.7717/peerj.18947Phylogeny of Cassieae based on seed morphological and ITS evidenceJing Cai0Chuang Yang1Leyang Wang2Jiaqing He3Qiang Wang4Hefei Preschool Education College, Hefei, Anhui, ChinaHefei Preschool Education College, Hefei, Anhui, ChinaHefei Preschool Education College, Hefei, Anhui, ChinaSchool of Life Science, Anhui University, Hefei, Anhui, ChinaNational Key Laboratory for Tea Plant Germplasm Innovation and Resource Utilization, Anhui Agricultural University, Hefei, Anhui, ChinaThe Cassieae tribe, comprising economically significant species, is understudied in terms of phylogenetics within China. This study aimed to elucidate the taxonomic status and systematic relationships among Cassieae species by integrating seed coat micro-morphological characteristics with molecular data from the internal transcribed spacer (ITS) region of nuclear ribosomal DNA. (1) The results indicate that the tribe is classified into seven distinct clades; Clade V consists of Chamaecrista, which is characterized by primarily monosymmetric flowers with occasional asymmetry, the presence of extrafloral nectaries (EFNs), five or ten stamens, and pods that dehisce elastically. Clade VI is associated with Senna, which displays polysymmetric or monosymmetric flowers, uniformly ten stamens or occasionally three staminodes, variable presence of EFNs, and predominantly indehiscent pods, with rare instances of slit dehiscence. Clade VII is characterized by the presence of Cassia, which exhibits polysymmetric flowers, consistently ten stamens—three of which are elongated and curved, typically exceeding the length of the petals—and indehiscent pods. (2) The monophyly of Cassia and Senna was strongly supported, with Cassia grouping closely with Senna, but distantly from Chamaecrista. (3) It is noteworthy that Senna occidentail and Senna sophera are confirmed as sister taxa, while Senna corymbosa and S. bicapsularis are confirmed as sister taxa. By integrating molecular biology and morphological taxonomy, this research enhances our comprehension of the phylogenetic relationships and evolutionary history within the Cassieae tribe in China.https://peerj.com/articles/18947.pdfCassiinaeEFNsSeed coat micro-morphologyITS regionPhylogeny
spellingShingle Jing Cai
Chuang Yang
Leyang Wang
Jiaqing He
Qiang Wang
Phylogeny of Cassieae based on seed morphological and ITS evidence
PeerJ
Cassiinae
EFNs
Seed coat micro-morphology
ITS region
Phylogeny
title Phylogeny of Cassieae based on seed morphological and ITS evidence
title_full Phylogeny of Cassieae based on seed morphological and ITS evidence
title_fullStr Phylogeny of Cassieae based on seed morphological and ITS evidence
title_full_unstemmed Phylogeny of Cassieae based on seed morphological and ITS evidence
title_short Phylogeny of Cassieae based on seed morphological and ITS evidence
title_sort phylogeny of cassieae based on seed morphological and its evidence
topic Cassiinae
EFNs
Seed coat micro-morphology
ITS region
Phylogeny
url https://peerj.com/articles/18947.pdf
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AT chuangyang phylogenyofcassieaebasedonseedmorphologicalanditsevidence
AT leyangwang phylogenyofcassieaebasedonseedmorphologicalanditsevidence
AT jiaqinghe phylogenyofcassieaebasedonseedmorphologicalanditsevidence
AT qiangwang phylogenyofcassieaebasedonseedmorphologicalanditsevidence