Figure 1 - uploaded by Wolfgang Maier
Content may be subject to copyright.
Phylogenetic reconstruction of Ravenelia species on different Vachellia hosts A Maximum likelihood tree with 1000 bootstrap repeats based on combined nrITS and LSU rDNA sequence data. Bootstrap values below 75 are not shown. Three highly supported groups represent R. evansii, R. macowaniana and R. xanthophloeae sp. nov., respectively. Specimens that originated from formerly unreported host species are highlighted in bold B Parsimony network analysis based on the same dataset as in the ML-analysis. Each line represents one base substitution while small circles represent intermediate but missing sequences. Numbers next to lines indicate the positions of the substitutions in the alignment. Sequences in rectangular boxes were inferred as ancestral by this analysis.
Source publication
Trees in the genus Vachellia (previously Acacia ) are commonly infected by the gall-inducing rusts Raveneliamacowaniana and R.evansii . Rust galls bearing aecial infections and relating uredinial and telial infections on the leaves of nine Vachellia species not previously recorded to be infected by Ravenelia spp. have recently been collected in Sou...
Contexts in source publication
Context 1
... phylogenetic tree of the combined rDNA sequence data set was deposited at TreeBASE (http://purl.org/phylo; submission IDS22307). Maximum likelihood analysis of the combined dataset resulted in a phylogenetic tree that consisted of three highly supported groups representing R. evansii, R. macow- aniana and a novel Ravenelia species described below (Fig. ...
Context 2
... parsimony network analysis, based on the combined set of nrITS and LSU rDNA sequence data, separated three distinct groups each comprising the same specimens representing R. evansii, R. macowaniana and the novel Ravenelia species in our phylogenetic analysis, respectively (Fig. 1B). Network analysis relying on LSU alone could not separate R. macowaniana from the novel taxon, while separa- tion of these two groups was observed based on nrITS alone (not shown). The R. evansii group consisted of six haplotypes of 17 sequences that differed by a maxi- mum of two substitutions from the inferred ancestral sequences ...
Context 3
... teliospore morphology of R. evansii specimens showed a considerable overall varia- bility in all six investigated teliospore characteristics (Suppl. material 1: Fig. S1, Table 2). The voucher specimens PREM61869 (on V. borleae), PREM61876 and PREM61868 (both on V. exuvialis) had significantly smaller teliospores compared to the remaining specimens, but variation in this trait could also be observed within single host associa- tions, e.g. within those from V. davyi and V. robusta (Suppl. material 1: ...
Context 4
... 1: Fig. S1, Table 2). The voucher specimens PREM61869 (on V. borleae), PREM61876 and PREM61868 (both on V. exuvialis) had significantly smaller teliospores compared to the remaining specimens, but variation in this trait could also be observed within single host associa- tions, e.g. within those from V. davyi and V. robusta (Suppl. material 1: Fig. ...
Context 5
... Furthermore, V. xanthophloea is apparently resistant to infection by the frequently co- occurring and closely related R. macowaniana. This observation lends additional support to the separation of R. macowaniana and R. xanthophloeae as distinct species. Sequence divergence was smaller amongst the specimens of R. evansii than within R. macowaniana (Fig. 1). This is in contrast to teliospore morphology, where the six examined teliospore traits showed considerable variability in R. evansii, but very little variation in R. macowaniana. Specifically, an effect of the host association on teliospore morphology could be demonstrated and this was most pronounced in specimens of R. evansii ...
Similar publications
The genus Ravenelia represents the third largest genus of rust fungi and parasitizes a great number of leguminous shrubs and trees, mainly in the subtropics and tropics. Molecular phylogenetic analyses of this genus using nc 28S rDNA and CO3 sequences are presented with a special focus on South African representatives of Ravenelia. Many of the spec...
Citations
... Vachellia and Senegalia and are well-known floral symbols of the continent with their wide spreading canopies (generally considered an adaptation to browsing) (Dreyfus & Dommergues, 1981;Ebinghaus et al., 2018). African savannas dominated by Vachellia and However, it is also considered that the high abundance of Vachellia and Senegalia improve soil fertility though the process of biological nitrogen fixation and their symbiotic relationship with rhizobia bacteria (Lamprey et al., 1974, Reid et al., 1999Barnes, 2001b;Bargali & Bargali, 2009;Van Auken & Bush, 2013). ...
The genera Vachellia and Senegalia, of the family Fabaceae, with most species in these genera able to biologically able to fix nitrogen, play a major role in structuring southern African savannas and determining their productivity. The biogeography of Vachellia and Senegalia shows that they dominate African savannas in regions of water stress, high herbivory by browsing mammals (e.g., giraffe) and relatively fertile soils. The characteristic discontinuous tree cover of savanna ecosystems suggests that a complex set of environmental factors such as drought, herbivory, and fire limit tree establishment during early demographic stages (seedling survival). Most species in these two genera have a capacity to biologically fix nitrogen via mutualism with rhizobial bacteria. These bacteria are free living in the soil and infect roots to form root nodules, where N2 is converted into plant useable NH4 that is used in growth. However, little is known under what environmental circumstances these plants fix nitrogen. A new understanding of how water stress and herbivory influence the growth and N2 fixation dynamics of seedlings and saplings can provide knowledge needed to help reconcile the dynamics of savanna vegetation at wider scales.
Here, I aimed to determine the effects of water availability and herbivory on nodule development in Vachellia and Senegalia during early life stages and examine links to plant performance. To investigate these relationships I worked on two experiments. First, I conducted a glasshouse experiment examining the relationship between nodulation and water availability in seedlings (Chapter 2). Second, I worked on a 30 month field experiment that enabled me to examine questions around an interaction between nodulation and herbivory (Chapter 3).
In the glasshouse experiment I investigated the effects of water availability on growth (height, root: shoot ratio, biomass) and nodulation in Vachellia sieberiana and Vachellia erioloba seedlings over a four month period (Chapter 2). The seedlings were watered at either 4%, 8% or 16% soil moisture and were harvested at month intervals (2 months – Harvest 1, 3 months – Harvest 2, or 4 months – Harvest 3) to track nodule and biomass development. V. erioloba did not nodulate and was unaffected by changes in soil moisture and V. sieberiana seedlings nodulated under all soil moisture treatments. V. sieberiana seedlings grown in the driest conditions (4%) had the lowest nodule count likely as a lack of soil moisture immobilises rhizobia were the tallest plants. However, the nodules of V. sieberiana grown in 4% SMC had the largest biomass. Seedlings grown in 16% had the highest nodule count, and the lowest biomass. However, V. sieberiana grown in 8% soil moisture had the highest rate of biological nitrogen fixation (BNF) likely to be a product of N demand, coupled with optimal conditions for the rhizobia living in the soil. It was clear that age mattered, and plants that were three months old or more nodulated more prolifically, supporting previous research. I conclude that N2 fixation is energy expensive to plant therefore will only be invoked if the benefits outweigh the costs, but due to the complexity of the relationship and the many influencing factors there is an optimal stress level. This optimal stress level is where N2 fixation is required due to disturbed conditions, but the disturbance cannot be so great that it hinders the rhizobia bacteria, limiting nodule development. Furthermore, the ability to nodulate under disturbed conditions has created a niche for V. sieberiana allowing it to take advantage of stress that may weaken surrounding vegetation.
In my third chapter, I investigated how browsing herbivory of seedlings impacts above and below ground biomass and nodulation in Vachellia sieberiana, Vachellia exuvialis, and Senegalia nigrescens saplings. My study was part of a larger experiment located at the Wits Rural Facility, South Africa examining plant survival. My study species were germinated from seed and subsequently exposed clipped to mimic browsing at 3 months, 4 months, or 4 months old, with control plots not clipped. Plants were grown for two growing seasons and I harvested them at 30 months of age. Plants of V. sieberiana exposed to herbivory had a lower biomass than control plants. In contrast, the biomass of V. exuvialis was unaffected by herbivory when clipped at three or four months of age. S. nigrescens clipped at three months of age were able to recover lost above ground biomass. For all three species nodulation was stimulated when clipping took place at three months old or greater. I suggest that nodulation and consequent fixation enables woody legumes to compensate for the effects of herbivory facilitating plant establishment and enabling plants to escape the “browse” trap.
Overall, I found evidence that an ability to nodulate and fix nitrogen provides species of Vachellia and Senegalia the opportunity to compensate for tissue loss and damage as a result of stress and disturbance during juvenile life stages. However, among the species studied here, there is wide variation in the functional traits and responses of individual species, likely due to the wide range of environmental niches occupied by the species of these genera. To date, little work has been undertaken examining nodulation in savanna woody legumes in response to stress and disturbance. While it had previously been shown that nodulation enabled young plants from Vachellia to compete with grasses during establishment, my data demonstrate for the first time that browsing herbivory can also induce nodulation. Future work should expand experiments to a wider array of species from these genera in order to determine the degree to which species responses to herbivory and water stress can be generalised. Nodulation enables Vachellia and Senegalia seedlings to survive at the critical and vulnerable stage of development following germination.
The genus Cerradoa (type species Cerradoa palmaea) was established in 1978 by Hennen and Ono and named after the Brazilian Cerrado biome. The holotype collected in Planaltina, Federal District, Brazil, belonged to the first rust fungus reported on palms (Arecaceae). For decades, the status of Cerradoa as a distinct genus has been regarded as doubtful, representing a synonym of Edythea (Uropyxidaceae) starting with the second edition of the Illustrated Genera of Rust Fungi in 1983. Our molecular phylogenetic analyses, as well as our morphological investigations, allowed us to reject this synonymy, leading to the reinstatement of Cerradoa within the Pucciniaceae. Cerradoa, together with morphologically similar genera such as the newly established Pseudocerradoa with two species (Ps. paullula and Ps. rhaphidophorae) infecting araceous hosts, the fern rust Desmella, and also P. engleriana, could not be assigned to any of the seven identified major lineages within the Pucciniaceae. Edythea, instead of being maintained as a member of the Uropyxidaceae, was herein placed in Pucciniaceae, shown phylogenetically in close relationship to Cumminsiella mirabilissima, both infecting the Berberidaceae. Additionally, our extensive phylogenetic analyses add guidance for future taxonomic revisions in the highly polyphyletic genus Puccinia and other established taxa within the family Pucciniaceae.
Fungi are eukaryotes that play essential roles in ecosystems. Among fungi, Basidiomycota is one of the major phyla with more than 40,000 described species. We review species diversity of Basidiomycota from five groups with different lifestyles or habitats: saprobic in grass/forest litter, wood-decaying, yeast-like, ectomycorrhizal, and plant parasitic. Case studies of Agaricus, Cantharellus, Ganoderma, Gyroporus, Russula, Tricholoma, and groups of lichenicolous yeast-like fungi, rust fungi, and smut fungi are used to determine trends in discovery of biodiversity. In each case study, the number of new species published during 2009–2020 is analysed to determine the rate of discovery. Publication rates differ between taxa and reflect different states of progress for species discovery in different genera. The results showed that lichenicolous yeast-like taxa had the highest publication rate for new species in the past two decades, and it is likely this trend will continue in the next decade. The species discovery rate of plant parasitic basidiomycetes was low in the past ten years, and remained constant in the past 50 years. We also found that the establishment of comprehensive and robust taxonomic systems based on a joint global initiative by mycologists could promote and standardize the recognition of taxa. We estimated that more than 54,000 species of Basidiomycota will be discovered by 2030, and estimate a total of 1.4–4.2 million species of Basidiomycota globally. These numbers illustrate a huge gap between the described and yet unknown diversity in Basidiomycota.
Rusts constitute a major group of the Kingdom Fungi and they are distributed all over the world on a wide range of wild and cultivated plants. It is the largest natural group of plant pathogens including 95% of the subphylum Pucciniomycotina and about 8% of all described Fungi. This article provides an overview and outline of rust fungi of India with important descriptive notes. After compilation of available literature on Indian rust fungi from various sources, it was observed that these fungi are distributed in 16 families, 69 genera and 640 species. They belong to Coleosporiaceae, Crossopsoraceae, Gymnosporangiaceae, Melampsoraceae, Milesinaceae, Ochropsoraceae, Phakopsoraceae, Phragmidiaceae, Pileolariaceae, Pucciniaceae, Pucciniastraceae, Raveneliaceae, Skierkaceae, Sphaerophragmiaceae, Tranzscheliaceae and Zaghouaniaceae. There are still many rust fungi with uncertain taxonomic position, and they have been referred to incertae sedis. The placement of all fungal genera is provided at the class, order and family-level along with number of species in a genus. Notes for each rust family along with total Indian records and other taxonomic information on transferred genera and species are also presented. A phylogenetic analysis from a combined LSU and ITS dataset for 25 rust genera is presented to provide a better understanding of their phylogeny and evolution.
Rusts constitute a major group of the Kingdom Fungi and they are distributed all over the world on a wide range of wild and cultivated plants. It is the largest natural group of plant pathogens including 95% of the subphylum Pucciniomycotina and about 8% of all described Fungi. This article provides an overview and outline of rust fungi of India with important descriptive notes. After compilation of available literature on Indian rust fungi from various sources, it was observed that these fungi are distributed in 16 families, 69 genera and 640 species. They belong to Coleosporiaceae, Crossopsoraceae, Gymnosporangiaceae, Melampsoraceae, Milesinaceae, Ochropsoraceae, Phakopsoraceae, Phragmidiaceae, Pileolariaceae, Pucciniaceae, Pucciniastraceae, Raveneliaceae, Skierkaceae, Sphaerophragmiaceae, Tranzscheliaceae and Zaghouaniaceae. There are still many rust fungi with uncertain taxonomic position, and they have been referred to incertae sedis. The placement of all fungal genera is provided at the class, order and family-level along with number of species in a genus. Notes for each rust family along with total Indian records and other taxonomic information on transferred genera and species are also presented. A phylogenetic analysis from a combined LSU and ITS dataset for 25 rust genera is presented to provide a better understanding of their phylogeny and evolution.
The rust fungi ( Pucciniales ) with 7000+ species comprise one of the largest orders of Fungi , and one for which taxonomy at all ranks remains problematic. Here we provide a taxonomic framework, based on 16 years of sampling that includes ca . 80 % of accepted genera including type species wherever possible, and three DNA loci used to resolve the deeper nodes of the rust fungus tree of life. Pucciniales are comprised of seven suborders – Araucariomycetineae subord. nov. , Melampsorineae , Mikronegeriineae , Raveneliineae subord. nov. , Rogerpetersoniineae subord. nov. , Skierkineae subord. nov. , and Uredinineae – and 18 families – Araucariomycetaceae fam. nov. , Coleosporiaceae , Crossopsoraceae fam. nov. , Gymnosporangiaceae , Melampsoraceae , Milesinaceae fam. nov. , Ochropsoraceae fam. & stat. nov. , Phakopsoraceae , Phragmidiaceae , Pileolariaceae , Pucciniaceae , Pucciniastraceae , Raveneliaceae , Rogerpetersoniaceae fam. nov. , Skierkaceae fam. & stat. nov. , Sphaerophragmiaceae , Tranzscheliaceae fam. & stat. nov. , and Zaghouaniaceae . The new genera Araucariomyces (for Aecidium fragiforme and Ae. balansae ), Neoolivea (for Olivea tectonae ), Rogerpetersonia (for Caeoma torreyae ), and Rossmanomyces (for Chrysomyxa monesis , Ch. pryrolae , and Ch. ramischiae ) are proposed. Twenty-one new combinations and one new name are introduced for: Angiopsora apoda , Angiopsora chusqueae , Angiopsora paspalicola , Araucariomyces balansae , Araucariomyces fragiformis , Cephalotelium evansii , Cephalotelium neocaledoniense , Cephalotelium xanthophloeae , Ceropsora weirii , Gymnotelium speciosum , Lipocystis acaciae-pennatulae , Neoolivea tectonae , Neophysopella kraunhiae , Phakopsora pipturi , Rogerpetersonia torreyae , Rossmanomyces monesis , Rossmanomyces pryrolae , Rossmanomyces ramischiae , Thekopsora americana , Thekopsora potentillae , Thekopsora pseudoagrimoniae , and Zaghouania notelaeae . Higher ranks are newly defined with consideration of morphology, host range and life cycle. Finally, we discuss the evolutionary and diversification trends within Pucciniales .
