scholarly journals Ecological adaptation and phylogenetic analysis of microsymbionts nodulating Polhillia, Wiborgia and Wiborgiella species in the Cape fynbos, South Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tiisetso Mpai ◽  
Sanjay K. Jaiswal ◽  
Christopher N. Cupido ◽  
Felix D. Dakora

AbstractPolhillia, Wiborgia and Wiborgiella species are shrub legumes endemic to the Cape fynbos of South Africa. They have the ability to fix atmospheric N2 when in symbiosis with soil bacteria called ‘rhizobia’. The aim of this study was to assess the morpho-physiological and phylogenetic characteristics of rhizobia associated with the nodulation of Polhillia, Wiborgia and Wiborgiella species growing in the Cape fynbos. The bacterial isolates from root nodules consisted of a mixture of fast and intermediate growers that differed in colony shape and size. The isolates exhibited tolerance to salinity (0.5–3% NaCl) and pH (pH 5–10) and different antibiotic concentrations, and could produce 0.51 to 51.23 µg mL−1 of indole-3-acetic acid (IAA), as well as solubilize tri-calcium phosphate. The ERIC-PCR results showed high genomic diversity in the rhizobial population and grouped them into two major clusters. Phylogenetic analysis based on 16S rRNA, atpD, glnII, gyrB, nifH and nodC gene sequences revealed distinct and novel evolutionary lineages related to the genus Rhizobium and Mesorhizobium, with some of them being very close to Mesorhizobium australicum. However, the phylogenetic analysis of glnII and nifH genes of some isolates showed incongruency.

2009 ◽  
Vol 23 (3) ◽  
pp. 193 ◽  
Author(s):  
Matjaž Kuntner ◽  
Ingi Agnarsson

Phylogenies are underutilised, powerful predictors of traits in unstudied species. We tested phylogenetic predictions of web-related behaviour in Clitaetra Simon, 1889, an Afro-Indian spider genus of the family Nephilidae. Clitaetra is phylogenetically sister to all other nephilids and thus important for understanding ancestral traits. Behavioural information on Clitaetra has been limited to only C. irenae Kuntner, 2006 from South Africa which constructs ladder webs. A resolved species-level phylogeny unambiguously optimised Clitaetra behavioural biology and predicted web traits in five unstudied species and a uniform intrageneric nephilid web biology. We tested these predictions by studying the ecology and web biology of C. perroti Simon, 1894 on Madagascar and C. episinoides Simon, 1889 on Mayotte. We confirm predicted arboricolous web architecture in these species. The expected ontogenetic allometric transition from orbs in juveniles to elongate ladder webs in adults was statistically significant in C. perroti, whereas marginally not significant in C. episinoides. We demonstrate the persistence of the temporary spiral in finished Clitaetra webs. A morphological and behavioural phylogenetic analysis resulted in unchanged topology and persisting unambiguous behavioural synapomorphies. Our results support the homology of Clitaetra hub reinforcement with the nephilid hub-cup. In Clitaetra, behaviour was highly predictable and remained consistent with new observations. Our results confirm that nephilid web biology is evolutionarily conserved within genera.


2009 ◽  
Vol 46 (9) ◽  
pp. 651-661 ◽  
Author(s):  
Constanze Bickelmann ◽  
Johannes Müller ◽  
Robert R. Reisz

A restudy of the Upper Permian diapsid Acerosodontosaurus piveteaui from Madagascar indicates that the bone formerly identified as the quadratojugal is a fragment of a rib. This in turn implies that, in contrast to previous studies, the lower temporal arcade must be considered incomplete and derived relative to the ancestral condition. Since the phylogenetic position of Acerosodontosaurus is poorly understood, the taxon was entered into a modified phylogenetic data matrix of diapsid reptiles, and the purported monophyly of “Younginiformes” was tested for the first time by including all potential members of the clade as separate taxa, as well as other taxa from the same deposits. The results of the phylogenetic analysis do not support the monophyly of “younginiform” reptiles. Instead, most taxa cluster unresolved at the base of Neodiapsida, a finding that has important implications for the understanding of early diapsid evolution because it suggests that early neodiapsids represent several distinct evolutionary lineages. Acerosodontosaurus and Hovasaurus do form a clade, a finding consistent with the stratigraphic age and biogeography of these taxa.


2010 ◽  
Vol 76 (13) ◽  
pp. 4587-4591 ◽  
Author(s):  
C. Talbi ◽  
M. J. Delgado ◽  
L. Girard ◽  
A. Ramírez-Trujillo ◽  
J. Caballero-Mellado ◽  
...  

ABSTRACT Phylogenetic analysis of 16S rRNA, nodC, and nifH genes of four bacterial strains isolated from root nodules of Phaseolus vulgaris grown in Morocco soils were identified as Burkholderia phymatum. All four strains formed N2-fixing nodules on P. vulgaris and Mimosa, Acacia, and Prosopis species and reduced acetylene to ethylene when cultured ex planta.


2015 ◽  
Vol 65 (Pt_2) ◽  
pp. 723-731 ◽  
Author(s):  
Ronel Roberts ◽  
Emma T. Steenkamp ◽  
Gerhard Pietersen

Greening disease of citrus in South Africa is associated with ‘Candidatus Liberibacter africanus’ (Laf), a phloem-limited bacterium vectored by the sap-sucking insect Trioza erytreae (Triozidae). Despite the implementation of control strategies, this disease remains problematic, suggesting the existence of reservoir hosts to Laf. The current study aimed to identify such hosts. Samples from 234 trees of Clausena anisata, 289 trees of Vepris lanceolata and 231 trees of Zanthoxylum capense were collected throughout the natural distribution of these trees in South Africa. Total DNA was extracted from samples and tested for the presence of liberibacters by a generic Liberibacter TaqMan real-time PCR assay. Liberibacters present in positive samples were characterized by amplifying and sequencing rplJ, omp and 16S rRNA gene regions. The identity of tree host species from which liberibacter sequences were obtained was verified by sequencing host rbcL genes. Of the trees tested, 33 specimens of Clausena, 17 specimens of Vepris and 10 specimens of Zanthoxylum tested positive for liberibacter. None of the samples contained typical citrus-infecting Laf sequences. Phylogenetic analysis of 16S rRNA gene sequences indicated that the liberibacters obtained from Vepris and Clausena had 16S rRNA gene sequences identical to that of ‘Candidatus Liberibacter africanus subsp. capensis’ (LafC), whereas those from Zanthoxylum species grouped separately. Phylogenetic analysis of the rplJ and omp gene regions revealed unique clusters for liberibacters associated with each tree species. We propose the following names for these novel liberibacters: ‘Candidatus Liberibacter africanus subsp. clausenae’ (LafCl), ‘Candidatus Liberibacter africanus subsp. vepridis’ (LafV) and ‘Candidatus Liberibacter africanus subsp. zanthoxyli’ (LafZ). This study did not find any natural hosts of Laf associated with greening of citrus. While native citrus relatives were shown to be infected with Laf-related liberibacters, nucleotide sequence data suggest that these are not alternative sources of Laf to citrus orchards, per se.


Bothalia ◽  
1972 ◽  
Vol 10 (4) ◽  
pp. 599-614 ◽  
Author(s):  
M. J. A. Werger ◽  
F. J. Kruger ◽  
H. C. Taylor

The Braun-Blanquet phytosociological method was tested in the complex Fynbos vegetation of the South-western Cape Region o f South Africa. In the Swartboschkloof Nature Reserve, Jonkers- hoek, the Fynbos, riverine scrub and forest vegetation was classified preliminarily into eight com­munities, which are described floristically and related to habitat. The results hold promise, and the possibilities of classifying the Cape Fynbos in a formal phytosociological system are discussed.


The Auk ◽  
2006 ◽  
Vol 123 (3) ◽  
pp. 660-680 ◽  
Author(s):  
Camila C. Ribas ◽  
Leo Joseph ◽  
Cristina Y. Miyaki

AbstractParakeets in the genus Pyrrhura occur in Amazonia and in almost all other major Neotropical forests. Their uneven distribution (with some widespread and several geographically restricted endemic taxa) and complex patterns of plum- age variation have long generated a confused taxonomy. Several taxonomically difficult polytypic species are usually recognized. Here, we present a mitochondrial DNA (mtDNA) phylogenetic analysis of Pyrrhura, with emphasis on the especially problematic picta-leucotis complex, to provide a more robust basis for interpreting the systematics and historical biogeography of the group. Our main findings are that (1) Pyrrhura can be divided into three main evolutionary lineages, one comprising P. cruentata, an Atlantic Forest endemic, the second comprising the picta-leucotis complex, and the third comprising the remaining species; (2) the traditionally recognized species P. picta and P. leucotis are not monophyletic; and (3) most of the species recognized by Joseph (2000, 2002) are diagnosable as independent evolutionary units, with the exception of the following species pairs: P. snethlageae and P. amazonum, P. leucotis and P. griseipectus, and P. roseifrons and P. peruviana. Other than P. cruentata, the two clades that constitute Pyrrhura appear to have radiated and evolved their present mtDNA diversity over short periods during the Plio-Pleistocene.Sistemática Molecular y Patrones de Diversificación en Pyrrhura (Psittacidae), con Énfasis en el Complejo Picta-Leucotis


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