Molecular differentiation of the Murraya paniculata Complex (Rutaceae: Aurantioideae: Aurantieae)

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Background: Orange jasmine has a complex nomenclatural history and is now known asMurraya paniculata(L.) Jack. Our interest in this common ornamental stemmed from the need to resolve its identity and the identities of closely related taxa as hosts of the pathogen ‘CandidatusLiberibacter asiaticus’ and its vectorDiaphorina citri. Understanding these microbe-vector-plant relationships has been hampered by taxonomic confusion surroundingMurrayaat both the generic and specific levels.Results: To resolve the taxonomic uncertainty, six regions of the maternally-inherited chloroplastal genome and part of the nuclear-encoded ITS region were amplified from 85 accessions ofMurrayaandMerrilliausing the polymerase chain reaction (PCR). Clustering used maximum parsimony (MP), maximum likelihood (ML) and Bayesian inference (BI). Chronograms were produced for molecular dating, and to test the monophyly ofMurrayarigorously, using selected accessions ofMurrayaand 26 accessions of the Rutaceae and Simarubaceae. Sequence data from the ITS and chloroplastal regions suggest thatMurraya paniculata(sensu (Swingle WT and Reece CR, The Citrus Industry, p. 190–430, 1967)) can be separated into four distinct but morphologically somewhat cryptic taxa:Murraya paniculata(sensu (Mabberley DJ, Taxon 65:366–371, 2016)),M. elongata,M. sumatranaandM. lucida. In addition,Murraya omphalocarpawas identified as a putative hybrid ofM. paniculataandM. lucidawith two geographically isolated nothovarieties representing reciprocal crosses.Murrayais monophyletic, and molecular dating suggests that it diverged fromMerrilliaduring the Miocene (23–5 Ma) with thisMurrayagroup speciating and dispersing during the Middle Miocene onwards.Conclusions: The accessions from Asia and Australasia used in this study grouped into biogeographical regions that match herbarium specimen records for the taxa that suggest natural allopatric distributions with limited overlap and hybridity.Murraya paniculatahas been distributed around the world as an ornamental plant. The division of theMurraya paniculatacomplex into four species with a rare hybrid also confirms morphological studies.
Funding Information
  • Australian Center for International Agricultural Research (na)
  • Plant Protection Research Institute (na)

This publication has 65 references indexed in Scilit: