Molecular identification and comparative analysis of novel 18S ribosomal RNA genomic sequences of a wide range of medicinal plants

摘要

Ribosomal RNAs (rRNAs) are universally distributed and known for their functional equivalence among all the known organisms. Analysis of small-subunit rRNAs (16-18S rRNAs) can permit the accurate statistical measurement of a broad range of phylogenetic relationships due to highly conserved sequences. Therefore, we identified and partially sequenced novel isoforms of 18S rRNA gene from 7 wild, medicinal plants (Ferocactus glaucescens, Capparis decidua, Calatropis procera, Maytenus royleana, Prosopis Juliflora, Ficus carica and Mentha spicata) and three cultivated plants (Cyamopsis tetragonoloba, Eruca sativa and Solanum lycopersicum). The genomic sequences of 18S rRNA from all of these diverse plants were analyzed and confirmed by using bioinformatics tools and submitted to genebank. We used ClustalW for pairwise alignment of these novel sequences with other known 18S rRNA sequences to find out their phylogenetic relationships. Our results have shown highly conserved nature of 18S rRNA with variable regions might be indications of some historical signals. Secondary structure constrains of rRNA can affect their phylogenetic interpretations rarely. These novel 18S rRNA sequences can also be used as internal controls for several types of molecular analysis after accurate validations of their consistent expression in the given plant species in future studies, as less is known about these housekeeping genes of wild plants.