Department of Botany, Panjab University, Chandigarh, 160014, India.
Mol Biol Rep. 2024 May 24;51(1):668. doi: 10.1007/s11033-024-09582-7.
The species of genus Ageratum (family Asteraceae) are distributed in various parts of the world. Ageratum conyzoides and A. houstonianum are the most commonly occurring species in India. These species are quite similar in their morphology thus creating a challenge in identification during the field survey and taxonomic validation. The accurate identification of the species is highly significant especially when those are of medicinal interest. To overcome the barriers in morphological based identification, DNA barcoding has been employed during the present investigation.
Morphological and DNA barcodes matK and ITS genes, were employed to differentiate between Ageratum conyzoides and A. houstonianum. The obtained matK and ITS gene sequences were submitted to GenBank and BOLD system to obtain accession numbers. The DNA sequences were aligned with database sequences using BLAST and phylogenetic trees were constructed through neighbor-joining algorithm in MEGA 11 software. The distinguish features of A. conyzoides include ovate to elliptic-oblong leaves with a cuneate base and inflorescence heads forming domed to flat-topped clusters. However, A. houstonianum has triangular to ovate leaves with a cordate to truncate base, cymose clusters in the inflorescence and stipulate glandular involucre bracts. The matK gene has shown the highest identity percentages (100%) for A. houstonianum and 99.87% for A. conyzoides. The phylogenetic tree analysis has demonstrated a close association of A. conyzoides and A. houstonianum with their respective species, supported by bootstrap values in the matK and ITS trees.
This study revealed that morphological and molecular data can be successfully utilized in the identification of A. conyzoides and A. houstonianum. The matK and ITS barcodes provide promising results in the identification of Ageratum species, with their phylogeny supporting classification within the family asteraceae.
苍耳属（菊科）的物种分布于世界各地。在印度，苍耳 Ageratum conyzoides 和 A. houstonianum 是最常见的物种。这些物种在形态上非常相似，因此在野外调查和分类验证中识别它们具有一定的挑战性。对物种的准确识别非常重要，特别是当它们具有药用价值时。为了克服基于形态的鉴定障碍，本研究采用了 DNA 条形码技术。
使用形态学和 DNA 条形码 matK 和 ITS 基因来区分苍耳 Ageratum conyzoides 和 A. houstonianum。获得的 matK 和 ITS 基因序列已提交给 GenBank 和 BOLD 系统以获取访问号。使用 BLAST 将 DNA 序列与数据库序列进行比对，并使用 MEGA 11 软件中的邻接法构建系统发育树。A. conyzoides 的特征包括卵形到长椭圆形的叶片，楔形基部和头状花序形成圆顶到平顶的簇。然而，A. houstonianum 具有三角形到卵形的叶片，心形到截形基部，聚伞状花序和具腺体的总苞片。matK 基因显示 A. houstonianum 的最高同一性百分比（100％），而 A. conyzoides 为 99.87％。系统发育树分析表明，A. conyzoides 和 A. houstonianum 与各自的物种密切相关，这得到了 matK 和 ITS 树中支持值的支持。
本研究表明，形态学和分子数据可成功用于鉴定 A. conyzoides 和 A. houstonianum。matK 和 ITS 条形码在鉴定苍耳属物种方面提供了有希望的结果，其系统发育支持在菊科内的分类。
