Abstract:
Large-scale DNA barcoding provides a new technique for species
identification and evaluation of relationships across various levels
(populations and species) and may reveal fundamental processes in recently
diverged species. Here, we analysed DNA sequence variation in the recently
diverged legumes from the Psoraleeae (Fabaceae) occurring in the Cape
Floristic Region (CFR) of southern Africa to test the utility of DNA barcodes in
species identification and discrimination. We further explored the phylogenetic
signal on fire response trait (reseeding and resprouting) at species and
generic levels. We showed that Psoraleoid legumes of the CFR exhibit a
barcoding gap yielding the combination of matK and rbcLa (matK + rbcLa) dataset as a better barcode than single regions. We found a high score
(100%) of correct identification of individuals to their respective genera but
very low score (<50%) in identifying them to species. We found a
considerable match (54%) between genetic species and morphologicallydelimited
species. We also found that different lineages showed a weak but
significant phylogenetic conservatism in their response to fire as reseeders or
resprouters, with more clustering of resprouters than would be expected by
chance. These novel microevolutionary patterns might be acting continuously
over time to produce multi-scale regularities of biodiversity. This study
provides the first insight into the DNA barcoding campaign of land plants in
species identification and detection of phylogenetic signal in recently diverged
lineages of the CFR.
