Molecular Phylogeny of Selected Kenyan Eucalyptus Species Inferred from MatK, rbcL and TrnL-F Genes and Their Suitability for Power Transmission Poles

Abstract

Genus Eucalyptus belongs to the family Myrtaceae and consists of more than 900 species, various hybrids and varieties. The major species that are grown in Kenya are Eucalyptus grandis, E. globulus, E. saligna and E. camaldulensis. Most Eucalyptus species are highly dependent on rainfall and this is challenged by climatic changes owing to global warming making it difficult to effectively match the availability of mature trees and the market demand especially for use as power transmission poles. With the widespread availability of other naturally occurring Eucalyptus species such as E. camaldulensis and E. globulus, it becomes important to determine the genetic diversity and to analyze the phenotypic traits of these species for suitability as power transmission poles in order to counter the overdependence on E. grandis. Phenotypic traits investigated included measuring total tree height and diameter at breast height (DBH), while molecular data were obtained from sequencing MatK, rbcL and TrnL-F genes from selected species and evolutionary analyses such as nucleotide substitution rates, base composition disparity indices, evolutionary divergence, nucleotide diversity indices and phylogeny construction were conducted in MEGA 11. Significant differences in DBH and height among Eucalyptus species were observed when the phenotypic data were subjected to ANOVA. In this study, E. robusta, E. paniculata, E. maculata, E. dunnii, E. camaldulensis and E. citriodora are fit to be used as power transmission poles but they are limited by their short height. However, E. tereticornis and E. glaucina have the desired DBH and height and hence can be used as substitutes for E.grandis. Generally, the molecular phylogeny study has shown that the studied Eucalyptus species are closely related and form various monophyletic clades which can be attributed to the short genetic distances, low substitution rates, low nucleotide bias disparity indices and low diversity scores. Further phylogenetic and gene expression studies involving more Eucalyptus species are needed to better understand Eucalyptus phylogeny, and diversity and identify species with similar genetic make-up to that of E. grandis which has been used extensively for the provision of electricity transmission poles.

Genetic variation and phylogenetic position of Taxus sumatrana (Miq.) de Laub. (Taxaceae) in Sumatra, Indonesia based on trnL-trnF region

“…However, in general nucleotide composition T. sumatrana from Sumatra has a similarity with the sequence from GenBank. The GC content is higher than AT content, causing a more stable bond for this region (Borisova et al 1993;Chebet et al 2022) explain that the trnL-trnF region is a conservative region, where this region that has remained essentially unchanged throughout evolution.…”

“…The trnL-trnF region is one of the recommended regions for DNA Barcode (Zanjanchi and Mehrvarz 2015;Sevindik et al 2019;Sanna et al 2019;Sevindik and Okan 2020;Yi et al 2021;Hocaoglu-Ozyigit et al 2022). The region has a conservative secondary structure and contains homologous elements throughout land plants, the sequence is catalytic, and this region can be used for evolutionary studies at higher taxonomic levels (Chebet et al 2022). The trnL-trnF gene is widely used since the 1990s (D'yachenko et al 2015;Hartvig et al 2015;Koohdar and Sheidai 2022;Kipkiror et al 2023), and has shown successful application in plant molecular systematics in flowering plants (Chen et al 2013), such as Mangifera spp.…”

Growing Eucalypt Outside its Native Range: A Review on Suitability and Beneficial Role

“…E ucalypt (safeda) is evergreen, fastest growing multipurpose species (MPTs), widely adopted in various climatic conditions. It belongs to the Myrtaceae family, with three genera such as Eucalyptus, Corymbia and Angophora comprising about 900 species (Pereira et al, 2014;Mengistu et al, 2020;Chebet et al, 2022). More than 700 known eucalypt species are native to Australia (Hooga et al, 2019) and few species are indigenous to Indonesia, the Philippines and New Guinea (Stanturf et al, 2013;Hayat et al, 2015).…”