Molecular Phylogeny of ten Kenyan Plectranthus species in the Coleus clade

Musila FM, Lukhoba CW, Dossaji SF, Nguta JM. "Molecular Phylogeny of ten Kenyan Plectranthus species in the Coleus clade.". In: XXI AETFAT congress. Catholic University of Eastern Africa, Nairobi, Kenya; 2017.

Date Presented:

18 May


Plectranthus is one important genus of flowering plants whose member species have a variety of uses in the horticultural and in the medical field. Plectranthus species are difficult to distinguish morphologically and many species have been given different names by different authors. Use of morphological characters is not sufficiently enough to delimit the genus successfully. Molecular, anatomical and biochemical markers are better in studying interspecific variation compared to gross morphological markers. So far no study on molecular phylogeny of the Kenyan Plectranthus species has been conducted. By comparing the same gene sequence across species within a genus, a phylogenetic tree can be constructed which can support or give new insights into the existing classification and rule out the confusion brought by synonymy. As a result, the current study used molecular characters to classify ten Plectranthus species in the Coleus clade within the Plectranthus genus. The molecular characters used in the study were DNA sequences of two chloroplast genes: MatK and Rbcl genes considered as universal molecular markers. Genomic DNA from the ten species was obtained followed by amplification and sequencing of the two genes in each species. From the results, a phylogenetic tree reconstructed using MatK genes groups P. caninus, P. otostegioides, P. barbatus and P. lanuginosus together and all the four species form a monophyletic group. These four species together with P.aegyptiacus form a larger monophyletic group. The same pattern can be observed in the phylogenetic tree created using the Rbcl genes. Again based on the MatK genes; P. pseudomarruboides, P. ornatus, P. montanous and P. amboinicus have been showed to be closely related and are monophyletic. Again these four species together with P.edulis form a larger monophyletc group. This close relationship of these species can also be observed in phylogenetic tree produced using the Rbcl genes. The present study has grouped the ten study Plectranthus species using molecular characters into phylogenies which are supported by previous studies and proved that molecular characters can aid in plant identification and phylogenetic studies.
Key words; Plectranthus, Molecular phylogeny, MatK gene, Rbcl gene.

aetfat_2017-fredrick_m.ppt1.91 MB

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