The importance of species identity in the biocontrol process: identifying the subspecies of Acacia nilotica (Leguminosae : Mimosoideae) by genetic distance and the implications for biological control

Wardill, Trevor J., Graham, Glenn C., Zalucki, Myron, Palmer, William A., Playford, Julia and Scott, Kirsten D. (2005) The importance of species identity in the biocontrol process: identifying the subspecies of Acacia nilotica (Leguminosae : Mimosoideae) by genetic distance and the implications for biological control. Journal of Biogeography, 32 12: 2145-2159. doi:10.1111/j.1365-2699.2005.01348.x


Author Wardill, Trevor J.
Graham, Glenn C.
Zalucki, Myron
Palmer, William A.
Playford, Julia
Scott, Kirsten D.
Title The importance of species identity in the biocontrol process: identifying the subspecies of Acacia nilotica (Leguminosae : Mimosoideae) by genetic distance and the implications for biological control
Journal name Journal of Biogeography   Check publisher's open access policy
ISSN 0305-0270
Publication date 2005
Sub-type Article (original research)
DOI 10.1111/j.1365-2699.2005.01348.x
Volume 32
Issue 12
Start page 2145
End page 2159
Total pages 15
Editor Robert J. Whittaker
Place of publication Oxford
Publisher Blackwell Publishing Ltd
Collection year 2005
Language eng
Subject C1
270401 Plant Systematics, Taxonomy and Phylogeny
779904 Control of pests and exotic species
0406 Physical Geography and Environmental Geoscience
Formatted abstract
Aims
A molecular genetic distance study has been used in an initial survey to identify subspecies and genotypes of the weed Acacia nilotica in Australia, information needed to find suitable biocontrol agents. We use patterns of DNA sequence variation (in two DNA fragments) from each of the nine described subspecies of Acacia nilotica (L.) Delile (Leguminosae: Mimosoideae) that is to determine their genetic similarity, to verify if the Australian populations are A. nilotica ssp. indica (Benth.) Brenan, and to establish if any other subspecies are present in Australia.

Location

Australia and southern Africa through the Arabian peninsular to the Indo-Pakistan subcontinent.

Methods
Representative specimens from the global distribution of the nine A. nilotica subspecies were sourced primarily from herbaria sheet specimens where available, and secondarily from field collections. These specimens together with related outgroups from Mimosoideae were genetically analysed using the DNA fragments trnL and internal transcribed spacer one (ITS1). We calculated a similarity index as set out in paup* using upgma (Unweighted Pair-Group Method Arithmetic average) methods to cluster taxa to produce a genetic distance phenogram.

Results
Sequence results from ITS1 and trnL DNA fragments identified seven of the described subspecies of A. nilotica. Acacia nilotica ssp. cupressiformis (J. Stewart) Ali & Faruqi and A. nilotica ssp. adstringens (Schumach. & Thonn.) Roberty were not found to be genotypically distinct from A. nilotica ssp. indica and A. nilotica ssp. nilotica, respectively, based on the two DNA fragments. Subspecific ITS1 genotypes were geographically distributed similarly to previous reports that were based on morphology, with the exception that the hemispherica ITS1 genotype also occurred in Somalia. We confirmed that the Australian A. nilotica populations are mostly comprised of subspecies indica, but in addition, some individuals were found to be genetically identical to an unidentified Pakistan genotype not previously reported as occurring in Australia.

Main conclusions
Australian A. nilotica populations originated from India and Pakistan and we recommend further analysis to determine the complete genetic diversity profile and origins of the Australian populations. We highlight the importance of determining any hybridization between Australian populations of A. nilotica and native subgenus Acacia species. This study demonstrates the importance of genotyping weed species targeted for biocontrol and/or listed host specificity test species that may be easily misidentified. Biocontrol practitioners can justify genetic studies by considering the costs should a project fail through misidentification.
Keyword Ecology
Geography, Physical
Diagnostic
Distribution
Genetic Distance
Hybridization
Internal Transcribed Spacer
Misidentification
Origin
Taxonomy
Trnl
Mating System-analysis
Intron Spacer Regions
Matk Coding Sequence
Chloroplast Dna
Molecular Phylogenetics
Natural-population
Control Agents
Ssp Indica
Weed
Q-Index Code C1

 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 25 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 28 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Wed, 15 Aug 2007, 07:10:44 EST