Morphological variation, species delimits, and phylogenetic relationships of four important Ipomoea species in Sri Lanka

P.G.R.G Rathnayake,H.S.M Jayarathne,W.W.M.U.K Wijesundara,W.G.A.S Sumanarathne,L.T Ranaweera,S.D.S.S Sooriyapathirana,R Salih,C.K Weebadde

doi:10.4038/sljae.v2i1.26

P.G.R.G Rathnayake, H.S.M Jayarathne + Show 6 more

Open Access

https://doi.org/10.4038/sljae.v2i1.26

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Abstract

Genus Ipomoea is the largest of the family Convolvulaceae. It is a highly diverse genus distributed all around the world. In Sri Lanka, 13 members have been identified in Ipomoea; however, most of them have not been morpho-genetically characterized. In the present study, we selected I. batatas, I. aquatica, I. nil, and I. pes-caprae for the assessment based on certain criteria viz., food security, leafy vegetable, emergent weed, and coastal conservation capabilities. The morphological variation, species delimits, and phylogenetic relationships among these four species were assessed. The DNA was extracted from young leaf samples using CTAB method and subjected to PCR using ITS and rbcL as markers. The PCR products were subjected to sequencing. The DNA sequences were analyzed, and phylogenetic trees were generated by using PAUP to define the species delimits, identify the speciation and evolutionarily relationships in comparison to the homologous Ipomoea sequences available in GenBank. The tuber bearing ability, flower colour, and leaf shape are the key morphological descriptors that can be used to delimit the selected species. Both rbcL and ITS markers could be used to identify the four species studied distinctively. However, among the two markers, ITS provides a greater variation to identify the four species and their evolutionary relationships. Thus, the present study provides a key platform with usable morphological traits and DNA barcoding markers to characterize all Ipomoea species in Sri Lanka.

Highlights

Ipomoea is a plant genus containing a group of warm climate trees, vines, and shrubs that are distributed mostly in the tropical and temperate zones in the world
Ipomoea is a highly diverse genus comprising of more than 500 different species. It is the largest genus in the flowering plant family Convolvulaceae, which predominantly consists of 1650 tropical species grouped into 50-60 genera (Austin and Huáman 1996)
Four species, I. batatas, I. aquatica, I. nil, and I. pescaprae, were selected for the assessment in the present study based on food and medicinal values, weed properties and ecological and soil conservation properties respectively

Summary

Introduction

Ipomoea is a plant genus containing a group of warm climate trees, vines, and shrubs that are distributed mostly in the tropical and temperate zones in the world. Ipomoea is a highly diverse genus comprising of more than 500 different species. It is the largest genus in the flowering plant family Convolvulaceae, which predominantly consists of 1650 tropical species grouped into 50-60 genera (Austin and Huáman 1996). Most species in Convolvulaceae are climbing or twinning woody or herbaceous plants that frequently possess heart-shaped leaves and funnel-shaped flowers (Lobin 1986). Sri Lanka is one of the tropical countries with very high diversity, which includes 13 species of the genus Ipomoea (Table 1). Four species, I. batatas, I. aquatica, I. nil, and I. pescaprae, were selected for the assessment in the present study based on food and medicinal values, weed properties and ecological and soil conservation properties respectively

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