Botany and Microbiology Department, Faculty of Science, Zagazig University, Zagazig, 44519, Egypt.
Biology Department, Faculty of Science, Jazan University, Jazan, Saudi Arabia.
BMC Plant Biol. 2022 Apr 20;22(1):205. doi: 10.1186/s12870-022-03543-7.
The genus Cassia and Senna have been classified under subfamily Caesalpinioideae of family Fabaceae (Leguminosae) of order Fabales. There is a scarce taxonomical studies of the genus Cassia and Senna inhabiting Egyptian environments, thus, the main objective of the current was to revise and authenticate the phylogenetic relationship between studied taxa of the species of the genera Cassia and Senna in Egypt using the recent tools of ITS barcoding, RAPD analysis and metabolic profiling, in comparing to the traditional taxonomical features. From the cluster analysis of the traditional 27 morphological characters, the studied taxa were categorized into two major clades with an average taxonomic distance of 4.3. The clade I include Cassia fistula, C. renigera, C. javanica L subsp. nodosa and C. roughiia that belongs to series Obolospermae, and C. grandis that belongs to series Grandes. The clade (II) includes Senna surattensis and S. alata at taxonomic level 3.6. The taxonomical description of the studied taxa was confirmed from the molecular analysis of ITS sequences and RAPD analysis. The ITS sequences of the tested plants species C. fistula L, C. grandis MD4, C. javanica subsp. nodosa MD7, C. roxburghii MD5, C. renigera MD5 were deposited at genbank with accession numbers MW367973, MZ960447, MW386305, MW326753 and MW32685, respectively. While, the ITS sequences of the S. surrattensis and S. alata were deposited into genbank accession # MD14 MW367670 and MD20 MW412635, respectively. Thus, from the molecular analysis, two clades were clearly separated into Clade I of Cassia and Clade II of Senna. The cluster I represented by C. fistula, C. renigera, C. roxburghii, and C. javanica sub nodosa, and the cluster II represented by S. alata and S. surattensis. From the PCA of RAPD, a clearly discrimination between the two Taxa was observed revealing the characteristic grouping of Cassia and Senna. The species Senna alata and Senna surattensis were grouped together, but the species of C. renigera, C. javanica, C. roxburghii and C. grandis was grouped on a distinct group. The separation of Cassia and Senna species into two clusters verify the segregation of the genus Cassia L. senso lato into two distinct genera namely Senna P. and Cassia L. The morphological, molecular traits of the studied plants were authenticated from the metabolic profiling by GC-MS analysis. Among the 23 identified metabolites, four compounds namely hexadecanoic acid, methyl ester, 9-Octadecenoic acid (Z)-ethyl ester and Vitamin E were detected with fluctuated concentrations, among C. fistula, C. grandis, C. javanica subsp. nodosa and C. roxburghii. Conclusively, the traditional morphological features, molecular barcoding using ITS sequences, RAPD analysis and metabolic traits by GC-MS analysis, authenticates the taxonomical diversity of the genus Cassia and Senna.
决明属和番泻属被归类为豆科（豆科）黎豆目植物的亚科。埃及环境中决明属和番泻属的分类学研究很少，因此，本研究的主要目的是使用最近的 ITS 条形码、RAPD 分析和代谢谱分析工具，修订和验证埃及研究类群的种间系统发育关系，并与传统分类特征进行比较。从 27 个形态特征的聚类分析来看，研究类群分为两个主要分支，平均分类距离为 4.3。第一分支包括决明子、苦参、金合欢 L 亚种 nodosa 和 C. roughiia，属于 Obolospermae 系列，而 C. grandis 属于 Grandes 系列。第二分支（II）包括番泻叶和番泻叶，在分类学水平上为 3.6。通过 ITS 序列和 RAPD 分析的分子分析，确认了研究类群的分类描述。经过测试的植物种决明子 L、C. grandis MD4、C. javanica subsp. nodosa MD7、C. roxburghii MD5 和苦参 MD5 的 ITS 序列已在基因库中以 MW367973、MZ960447、MW386305、MW326753 和 MW32685 的形式进行了存储。同时，S. surrattensis 和 S. alata 的 ITS 序列分别存入 genbank accession # MD14 MW367670 和 MD20 MW412635。因此，从分子分析来看，两个分支清楚地分为决明子分支 I 和番泻叶分支 II。以决明子、苦参、金合欢和 C. javanica sub nodosa 为代表的分支 I，以及以番泻叶和番泻叶为代表的分支 II。从 RAPD 的 PCA 来看，观察到两个类群之间有明显的区分，揭示了决明子和番泻叶的特征分组。番泻叶和番泻叶被归为一组，但苦参、金合欢、C. javanica、C. roxburghii 和 C. grandis 被归为一组。决明子和番泻叶物种分为两个聚类验证了决明子属 L. 广义的分离为两个不同的属，即番泻叶 P. 和决明子 L.。通过 GC-MS 分析的代谢谱，对研究植物的形态、分子特征进行了鉴定。在鉴定出的 23 种代谢物中，检测到 4 种化合物，即十六烷酸甲酯、9-十八烯酸（Z）乙酯和维生素 E，在决明子、C. grandis、C. javanica subsp. nodosa 和 C. roxburghii 中浓度波动。总之，传统的形态特征、基于 ITS 序列的分子条形码、RAPD 分析和 GC-MS 分析的代谢特征，证实了决明子属和番泻叶属的分类多样性。
