Abstract Abstract
Two new rust species, Raveneliapiepenbringiae and R.hernandezii (Pucciniales) on Senegalia spp. (Fabaceae) are described from the Neotropics (Panama, Costa Rica). A key to the species on neotropical Senegalia spp. is provided. Molecular phylogenetic analyses based on 28S rDNA sequence data suggest that the representatives of Senegalia rusts distributed in the neotropics evolved independently from species known from South Africa. This is further supported by the teliospore morphology, which is characterised by uniseriate cysts in the neotropical Senegalia rusts and contrasting multiseriate cysts in the paleotropic Ravenelia species that infect this host genus.
Keywords: Senegalia rust, rust fungi, Phylogeny, Taxonomy
Introduction
With more than 200 described species, the genus Ravenelia is amongst the most speciose genera within the rust fungi (Pucciniales) (Cummins and Hiratsuka 2003). In the tropics and subtropics, members of this genus parasitise a diverse range of hosts of the legume family (Fabaceae), including Caesalpinioideae, Faboideae and Mimosoideae. Numerous species of Ravenelia are known from the neotropics, mostly from Mexico (Cummins 1978), Brazil (Dianese et al. 1993, Rezende and Dianese 2001; Hennen et al. 2005) and Argentina (Hernández and Hennen 2002).
However, in the neotropics, occurrence of Ravenelia species is poorly known in other countries such as Panama and Costa Rica. Preliminary checklists of abundant fungi in Central America report only a single species of Ravenelia in Panama (R.entadae) (Piepenbring 2006) and 18 species of Ravenelia in Costa Rica, respectively (Berndt 2004).
Specimens of a rust fungus on Senegaliahayesii (Benth.) Britton and Rose were collected in Panama in 2013. Another species of Ravenelia was discovered through the analysis of herbarium specimens of the U.S. National Fungal Collections (BPI) on Senegaliatenuifolia (L.) Britton and Rose. On the basis of morphological and molecular data, these two specimens were herein analysed and described respectively as Raveneliapiepenbringiae and R.hernandezii.
Material and methods
Light- and electron microscopic investigations
Spores representing different spore stages were scraped from the leaf surfaces of dried herbarium specimens and stained in lactophenol solution on microscope slides. For the analysis of soral structures, hand sections were prepared under a stereomicroscope. Samples were microscopically studied with a Zeiss Axioplan Light Microscope and Zeiss AxioCam. Cellular structures were measured using ZEN 2 (Blue Edition) Software. Infected leaflets of the herbarium specimens were mounted on double-sided sticky carbon tape on metal stubs and coated with gold in a Sputtercoater BAL-TEC SCD OSO (Capovani Brothers Inc, USA). Superficial ornamentation of spores was investigated using a ZEISS Sigma VP scanning electron microscope at the Ruhr-University Bochum, Germany.
DNA extraction and PCR
Genomic DNA extractions were carried out using the INNUPrep Plant DNA Kit (Analytic Jena, Germany) according to the manufacturer’s protocol. Spores were milled in a Retsch Schwingmühle MM2000 (F. Kurt Retsch GmbH &Co KG, Haan, Germany), using two steel beads and liquid nitrogen in three consecutive cycles. An amount of 40 ml of lysis buffer was added to loosen spore remnants by vortexing from the Eppendorf tube lid, followed by centrifuging in a final cycle. Polymerase chain reaction (PCR) of 28S rDNA was conducted using the Taq-DNA-Polymerase Mix (PeqLab, Erlangen, Germany). To compensate for small amounts of spores applied for DNA extractions up to 5ml of genomic DNA extraction were used as the template in 25 ml reactions. Primer pair LR0R (Moncalvo et al. 1995) and LR6 (Vilgalys and Heester 1990) were used to obtain sequences of the 28S rDNA, with thermal cycling conditions set at 96 °C (3 min) followed by 40 cycles of 30 sec at 95 °C, 40 sec at 49 °C and 1 min at 72 °C, with a final extension for 7 min at 72 °C. PCR products, which showed only weak bands on agarose gels, were purified with Zymo Research DNA Clean & Concentrator-5 Kit (ZymoResearch Corp., Irvine, USA), according to the manufacturer’s protocol. The remaining PCR products were purified using Sephadex G-50 columns (Sigma-Aldrich Chemie GmbH, Taufkirchen, Germany). Sequencing was carried out in both directions using the same primers as in PCR at the sequencing service of the Faculty of Chemistry and Biochemistry of the Ruhr-University Bochum, Germany and by GATC (GATC Biotech, Konstanz, Germany)
Phylogenetic analyses
Sequences were screened against the NCBI Genbank using the BLAST algorithm to check for erroneously amplified contaminations and were afterwards edited manually using Sequencher 5.0 software (Gene Codes Corp., Michigan, USA). In total, 26 sequences were included (Table 1) to construct an alignment of the 28S rDNA-sequence data using MAFFT v6.832b (Katoh and Standley 2013). Maximum likelihood (ML) analyses were performed with RxML 8.0.26 (Stamatakis 2014) using RAxML GUI v. 1.31 (Silvestro and Michalak 2012) based on the General Time Reversible model of nucleotide substitution plus gamma distribution (GTR+G; Rodriguez et al. 1990) and 1000 generations. Four representative species of Endoraecium (KJ862335, KJ862298, KJ862337, KJ862344) were set as multiple outgroups. Maximum Parsimony (MP) analyses were carried out using MEGA6 (Tamura et al. 2013) using the heuristic search option with tree bisection-reconnection (TBR) branch swapping algorithm with 10 initial trees using random step-wise addition. The reliability of topology was tested using the bootstrap method with 1000 replicates.
Table 1.
Specimens analysed in this study, including GenBank Accession Numbers. Published references are given for sequences obtained from GenBank. †: BPI (U.S. National Fungus Collections, USA); ‡: KR (Staatliches Museum für Naturkunde Karlsruhe, Germany); $: PREM (Plant Protection Research Institute, South Africa); |: Z+ZT (Universität Zürich, Switzerland and Eidgenössische Technische Hochschule Zürich, Switzerland); ¶: BRIP (Department of Agriculture and Fisheries, Australia); #: PMA (Universidad de Panamá, Panama).
| Voucher | Species | Substrate | Reference | Origin | LSU |
|---|---|---|---|---|---|
| GenBank | |||||
| BPI841185† | Raveneliacohniana Henn. | Senegaliapraecox (Grieseb.) Seigler & Ebinger | This work | Catamarca Province, Argentina | MG954487 |
| BPI841034† | Raveneliaechinatavar.ectypa (Arthur & Holw.) Cummins | Calliandraformosa (Kunth) Benth. | Scholler and Aime, 2006 | Tucuman Province, Argentina | DQ323925* |
| KR-M-0043650‡ | Raveneliaescharoides Syd. | Senegaliaburkei (Benth.) Kyal. & Boatwright | This work | Mpumalanga, South Africa | MG954480 |
| KR-M-0043651‡ | Raveneliaescharoides Syd. | Senegaliaburkei (Benth.) Kyal. & Boatwright | This work | Limpopo, South Africa | MG954481 |
| KR-M-0043652‡ | Raveneliaescharoides Syd. | Senegaliaburkei (Benth.) Kyal. & Boatwright | This work | Limpopo, South Africa | MG954482 |
| PREM61223$ | Raveneliaevansii Syd. | Vachelliasieberiana (Burtt Davy) Kyal. & Boatwr. | This work | KwaZulu-Natal, South Africa | MG945988 |
| PREM61228$ | Raveneliaevansii Syd. | Vachelliasieberiana (Burtt Davy) Kyal. & Boatwr. | This work | KwaZulu-Natal, South Africa | MG945989 |
| PREM61855$ | Raveneliahalsei Doidge | Senegaliaataxacantha (D.C) Kyal. & Boatwright | This work | Mpumalanga, South Africa | MG954484 |
| Z+ZT RB5788| | Raveneliahavanensis Arthur | Enterolobiumcontortisiliquum (Vell.) Morong | Aime, 2006 | Tucuman Province, Argentina | DQ354557* |
| BPI872308† | Raveneliahernandezii Ebinghaus & Begerow | Senegaliatenuifolia (L.) Britton & Rose | This work | Guanacaste, Costa Rica | MG954488 |
| PREM61222$ | Raveneliamacowaniana Pazschke | Vachelliakarroo (Hayne) Banfi & Galasso | This work | Limpopo Province, South Africa | MG946007 |
| PREM61210$ | Raveneliamacowaniana Pazschke | Vachelliakarroo (Hayne) Banfi & Galasso | This work | Eastern Cape Province, South Africa | MG946004 |
| PREM61221$ | Raveneliamacowaniana Pazschke | Vachelliakarroo (Hayne) Banfi & Galasso | This work | North-West Province, South Africa | MG946005 |
| BPI841195† | Raveneliamacrocarpa Syd. & Syd. | Sennasubulata (Griseb.) H.S. Irwin & Barneby | Scholler and Aime 2006 | Argentina | DQ323926* |
| BRIP56908¶ | Ravenelianeocaledoniensis Huguenin | Vachelliafarnesiana (L.) Wight & Arn. | McTaggart et al. 2015 | Kununurra, Australia | KJ862348* |
| BRIP56907¶ | Ravenelianeocaledoniensis Huguenin | Vachelliafarnesiana (L.) Wight & Arn. | McTaggart et al. 2015 | Northern Territory, Australia | KJ862347* |
| KR-M-0045114‡ | Raveneliapienaarii Doidge | Senegaliacaffra (Thunb.) P.J.H. Hurter & Mabb. | This work | Gauteng, South Africa | MG954483 |
| PREM61892$ | Raveneliapienaarii Doidge | Senegaliacaffra (Thunb.) P.J.H. Hurter & Mabb. | This work | KwaZulu-Natal, South Africa | MG954482 |
| MP5157 (PMA)# | Raveneliapiepenbringiae Ebinghaus & Begerow | Senegaliahayesii (Benth.) Britton & Rose | This work | Chiriquí Province, Panama | MG954489 |
| BRIP56904¶ | Ravenelia sp. | Cassia sp. Mill. | McTaggart et al. 2015 | Northern Territory, Australia | KJ862349* |
| PREM61858$ | Raveneliatransvaalensis Doidge | Senegaliamellifera (Vahl) Seibler & Ebinger | This work | North-West Province, South Africa | MG954485 |
| PREM61893$ | Raveneliatransvaalensis Doidge | Senegaliamellifera (Vahl) Seibler & Ebinger | This work | North-West Province, South Africa | MG954486 |
| BRIP56539¶ | Endoraeciumauriculiforme McTaggart & Shivas | Acaciadifficilis Maiden | McTaggart et al., 2015 | Northern Territory, Australia | KJ862398* |
| BRIP27071¶ | Endoraeciumtierneyi (Walker & Shivas) Scholler & Aime | Acaciaharpophylla F.Muell. ex Benth. | McTaggart et al. 2015 | Queensland, Australia | KJ862335* |
| BRIP56557¶ | Endoraeciumtropicum McTaggart & Shivas | Acaciatropica (Maiden & Blakely) Tindale | McTaggart et al. 2015 | Northern Territory, Australia | KJ862337* |
| BRIP56545¶ | Endoraeciumviolae-faustiae Berndt | Acaciadifficilis Maiden | McTaggart et al. 2015 | Northern Territory, Australia | KJ862344* |
Results
Phylogenetic analyses
The alignment of the 28S rDNA sequence data consisted of 26 sequences representing 18 taxa and had a total length of 1015 nucleotides with 305 variable characters, 250 parsimony-informative sites and 55 singletons. The tree topologies of MP and ML analyses were identical and thus only the ML tree is shown. A clade, comprising rusts on neotropical Senegalia species, i.e. R.cohniana, R.hernandezii sp. nov. and R.piepenbringiae sp. nov., displays a robustly supported sister-group (MLBS/MPBS = 99/100) to two neotropically distributed rusts which infect non-Senegalia hosts (i.e. R.echinatavar.ectypa on Calliandraformosa, DQ323925 and R.havanensis on EnterolobiumcontortisiliquumDQ354557) (Scholler and Aime 2006, Aime 2006). A second clade, based on sequences obtained from Ravenelia species on Senegalia spp. with paleotropical origin, appeared only distantly related to the former species cluster (MLBS/MPBS = 100/99) (Figure 1).
Figure 1.
Maximum likelihood reconstruction of Ravenelia spp. based on 28S rDNA sequence data. Bootstrap values are shown above branches based on 1000 replicates (MLBS and MPBS, respectively), values below 75 are not shown. Names of species collected on neotropical Senegalia hosts including R.piepenbringiae and R.hernandezii are highlighted (bold, red box). For paleotropically distributed species of Senegalia rusts, see black box.
Taxonomy
Ravenelia piepenbringiae
Ebinghaus & Begerow, sp. nov. on Senegalia hayesii (Benth.) Britton & Rose (Mimosoideae, Leguminosae)
Mycobank: MB 824297
Figure 2.
Raveneliapiepenbringiae. A Telia in chlorotic spots associated with infection of SenegaliahayesiiB, C sori showing uredinio- and teliospores and teliospores, respectively D SEM image of a telium E SEM view of a teliospore F, I LM images of teliospores G SEM image of urediniospores showing equatorially arranged germ pores H drawings of urediniospores. Scale bars: 3 mm (A); 0.1 mm (B); 0.2 mm (C); 40 mm(D); 10 mm (E); 20 mm(F); 5 mm(G); 10 mm(H); 20 mm(I).
Type.
Panama, Chiriquí Province, Dolega District, Los Algarrobos, Casa de la Alemana, Bosquecito, approx. 150 m a.s.l., 8°29'45.31"N, 82°25'56.24"W on Senegaliahayesii (Benth.) Britton and Rose, 17 February 2013, coll. M. Piepenbring MP 5157 [holotype: s.n. (PMA), isotypes: KR-M-0043654 (KR). M-0141345 (M)]
Etymology.
Named after M. Piepenbring, who discovered the rust fungus in her garden and provided the specimens.
Spermogonia and aecia not seen. Uredinia hypophyllous, single or in irregular groups, light brown, often associated with necrotic spots that are also evident on the adaxial surface, 0.1–0.8 mm in diameter, aparaphysate, subepidermal, covered by the epidermis when young, later erumpent. Urediniospores obovoidal, ellipsoidal or slightly curved, often limoniform with an acuminate apex, ochraceous brown, (18)21–25(29) × 12–15(20) mm; spore wall laterally 1–1.5 mm thick, apically and basally often slightly thickened, distinctly verrucose to echinulate; aculei 1.0–1.5 mm high, distances between aculei about 2 mm, germ pores 4–7, in equatorial position. Telia replacing uredinia or developing independently from uredinia, chestnut to dark brown, sometimes confluent. Teliospores roundish to broadly ellipsoidal to oblong in planar view, hemispherical in lateral view, with 4–6 probasidial cells across, single-layered, each teliospore formed by 9–13 probasidial cells, (44)58–73(78) mm in diameter, single probasidial cells (19)22–26(31) × (11)17–22(28) mm; cell wall thickened at the surface of the teliospore (epispore), 2–4(5) mm thick, often with a thin and hyaline outer layer, each probasidial cell with 7–11 rod-shaped, straight spines that are (1)2–3(4.5) mm long; cysts at the basis of the teliospores, uniseriate and in the same position and number as the peripheral probasidial cells, globose, hyaline, swelling in water, slightly swelling in lactophenol.
Further specimens. Type locality, 22 January 2014, M. Piepenbring 5203 [M-0141344 (M), s.n. (UCH)]. Type locality, 12 January 2017, M. Piepenbring & I. D. Quiroz González 5333 (UCH, s.n.).
Ravenelia hernandezii
Ebinghaus & Begerow, sp. nov. on Senegalia tenuifolia (L.) Britton and Rose (Mimosoideae, Leguminosae)
Mycobank: MB 824298
Figure 3.
Raveneliahernandezii. A Infected leaflets of S.tenuifoliaB Mixed sori containing urediniospores and teliospores C Teliospore seen in LM D telium seen by SEM E Adaxial view of a teliospore by LM, with arrows indicating the uniseriate cysts F SEM view of spinescent teliospores G LM view of the upper surface H drawing of a urediniospore. Scale Bars: 0.5 mm (A); 0.1 mm (B); 20 mm (C–G); 10 mm (H).
Type.
Costa Rica, Guanacaste, Area de Conservación Guanacaste, Sendero Bosque húmedo (10°50.702'N, 85°36.450'W) on Senegaliatenuifolia (L.) Britton and Rose, coll. J.R. Hernandez, 1. December 2003. Holotype: BPI 872308 (BPI).
Etymology.
Named after J.R. Hernández who collected the type specimen.
Spermogonia and aecia not seen. Uredinia hypophyllous, minute, single or in small and often loose groups, ochraceous to light brown, 0.1–0.3 mm in diameter, aparaphysate, subepidermal, erumpent and surrounded by torn epidermis; urediniospores obovoidal, ellipsoidal, often reniform or slightly curved, ochraceous brown, often with an attached fragment of the pedicel, (17)18–21(24) × (8)9–10(12) mm; spore wall thin, laterally (0.5)1–1.5 mm thick, apically and basally slightly thickened, distinctly echinulate; aculei approximately 1.0–1.5 mm high, germ pores 5–6, in equatorial position. Telia replacing uredinia, chestnut- to dark brown. Teliospores (59)67–75(96) mm, roundish or broadly ellipsoidal to oblong in planar view, hemispherical in lateral view, 5–6 probasidial cells across, single-layered, central cells often arranged in two rows of 3 or 4 cells, each cell (19)22–25(39) × (11)17–22(28) mm, cell wall thickened at the apex, (2.5)3.0–4.5(6.0) mm thick, often with a thin and hyaline outer layer, probasidial cells each with 3–5 rod-shaped straight spines (1)3–4(6) mm long; cysts on the abaxial side of the teliospores, uniseriate and in same position and number as the peripheral probasidial cells, globose, hyaline, swelling in water, slight swelling in lactophenol.
Discussion
A total of 10 species of Ravenelia have been described to date from the neotropics parasitising Senegalia trees: R.cohniana Hennings on S.praecox (Griseb.) Seigler & Ebinger, R.idonea Jackson & Holway, R.lata Hennen & Cummins on S.glomerosa (Benth.) Britton & Rose, R.monosticha Speg. on S.bonariensis (Gillies ex Hook. & Arn.) Seigler & Ebinger, R.pringlei Cummins on S.greggii (A. Gray) Britton & Rose, R.rata Jackson & Holway on S.pedicellata (Benth.) Seigler & Ebinger, R.roemerianae Long on S.roemeriana (Scheele) Britton & Rose, R.scopulata Cummins & Baxter on S.greggii (A. Gray) Britton & Rose, R.stevensii Arthur on S.riparia (Kunth) Britton & Rose ex Britton & Killip and R.versatilis (Peck) Dietel on S.anisophylla (Watson) Britton & Rose. No species of Ravenelia has been reported to affect Senegaliahayesii or S.tenuifolia. Most of these species known to parasitise Senegalia spp. are distinguished from species identified in this study by abundant paraphyses in the uredinia, except for Raveneliarata which also lacks paraphyses in the uredinia. However, this species differs from R.piepenbringiae and R.hernandezii by abundant tuberculate teliospore ornamentations 2–3µm in length and by formation of only 2–4 cysts per teliospore. Both newly described species exhibit longer tuberculate spines and bear 6–8 cysts per teliospore. Raveneliacohniana is the only species that resembles various teliospore and urediniospore characteristics of R.piepenbringiae and R.hernandezii (see Table 2). The teliospores of R.hernandezii, however, are larger in size than those of the latter two species (Table 2). In contrast to the teliospores, urediniospores of R.hernandezii tend to be smaller and more slender, while they mostly lack the characteristic acuminate apex present in urediniospores of R.piepenbringiae (Table 2; compare Figures 1H and 2H). Hernández and Hennen (2002) considered R.concinna Syd. on S.riparia (Kunth) Britton & Rose ex Britton & Killip and S.glomerosa, R.distans Arthur & Holway on an unidentified mimosoid host and R.lindquistii Hennen & Cummins on Senegaliapraecox as synonyms of R.cohniana due to a nearly identical morphology. However, given the likewise close morphological resemblance in R.piepenbringiae, R.hernandezii and R.cohniana, despite being phylogenetic entities, this assumption needs revision by molecular phylogenetic means.
Table 2.
Summary of morphological characteristics of Ravenelia species infecting Senegalia trees in the neotropics. All measurements are given in mm. Absent characters are indicated with dashes.
| Species | Teliospore characters | Source | ||||||||||
| Teliospore size | Probasidial cell size | Epispore | Ornamentation | Cells in Diameter | Arrangement of Cysts | |||||||
| Number per cell | length | shape | ||||||||||
| R. cohniana | (39)45–73(74) | 16–22 × 13–15 | not stated | (2)3–5(8). | 3–5 | spinescent | (3)4–5(6) | uniseriate | Hernández and Hennen (2002) | |||
| R. escharoides | 55–90 | 30–35 × 16–20 | up to 6 | 4–9 | 1–2 | verrucose | 6–8 | multiseriate | Doidge (1939) | |||
| R. halsei | 80–112 | 25–30 × 10–15 | 5–6 | – | – | smooth | 9–11 | uniseriate | Doidge (1939) | |||
| R. hernandezii | (59)67–75(96) | (19)22–25(39) × (11)17–22(28) | (2.5)3–4.5(6) | 3–5 | (1)3–4(6) | spinescent | 5–6 | uniseriate | This study | |||
| R. lata | 53–64 | (18)22–26 (width) | not stated | 6–20 | not stated | spinescent | 4 | multiseriate | Hennen et al. (2005) | |||
| R. monosticha | (50)53–55 × 65–70 | 16–19 × 13–15 | not stated | 4–8 | not stated | verrucose | 4–6 | uniseriate | Spegazzini (1923) | |||
| R. pienaarii | 80–120 | 25–30 × 10–15 | up to 7 | 4–7 | 1–1.5(2) | verrucose | (6)7–10 | multiseriate | Doidge (1939) | |||
| R. piepenbringiae | (44)58–73(78) | (19)22–26(31) × (11)17–22(28) | 2–4(5) | 7–11 | (1)2–3(4.5) | spinescent | 4–6 | uniseriate | This study | |||
| R. pringlei | (55)70–95(105) | (12)14–18(20) (width) | not stated | not stated | not stated | verrucose | (5)6–8 | uniseriate | Cummins (1975) | |||
| R. rata | (30)33–40(44) | 14–20 × 12–17 | 1.5 | not stated | 2–3 | verrucose | 2–4 | uniseriate | Hennen et al. (2005) | |||
| R. roemerianae | 63–100 | Not stated | not stated | 3–10 | 2 | verrucose | 5–7 | uniseriate | Long (1917) | |||
| R. scopulata | (55)65–100(110) | (13)16–19(21) (width) | not stated | not stated | not stated | smooth | 5–8 | multiseriate | Cummins and Baxter (1976) | |||
| R. stevensii | 40–63 | Not stated | not stated | 1–3 | 6–19 | verrucose | 3–6 | multiseriate | Arthur (1915) | |||
| R. transvaalensis | 75–100 | 30–35 × 15–17.5 | up to 6 | – | – | smooth | 5–6 | multiseriate | Doidge (1939) | |||
| R. versatilis | 85–105 | 10–16 (width) | not stated | – | – | smooth | 7–9 | not stated | Dietel (1894) | |||
| Paraphyses | Urediniospore characters | Source | ||||||||||
| Position | Shape | Size | Cell wall | Germ pores | Shape | |||||||
| Number | Position | |||||||||||
| R. cohniana | – | – | (12)20–28(32) × (11)13–17(19) | 1.5–2.5(3) | (3)4(6) | equatorial | oblong-ellipsoidal | Hernández and Hennen (2002) | ||||
| R. escharoides | – | – | 17–22×14–17 | 1.5 | Not stated | not stated | obovoidal-ellipsoidal | Doidge (1939) | ||||
| R. halsei | not stated | not stated | – | – | – | – | – | Doidge (1939) | ||||
| R. hernandezii | – | – | (17)18–21(24) × (8)9–10(12) | (0.5)1–1.5 | 5–6 | equatorial | obovoidal-ellipsoidal | This study | ||||
| R. lata | peripheral | capitate | (22)25–32(36) × (12)14–17(18) | 1.5–2 | (4)5–6 | equatorial | obovoidal-oblong | Hennen et al. (2005) | ||||
| R. monosticha | peripheral | capitate | (23)26–30(33) × (8)12–14(15) | 1.5–2 | 4–5(6) | equatorial | obovoidal-ellipsoidal | Spegazzini (1923) | ||||
| R. pienaarii | – | – | 20–25 × 15–19 | 1.5 | 6 | equatorial | ellipsoidal-subglobose | Doidge (1939) | ||||
| R. piepenbringiae | – | – | (18)21–25(29) × 12–15(20) | 1–1.5 | 4–7 | equatorial | obovoidal-limoniform | This study | ||||
| R. pringlei | not stated | clavate - capitate | (10)11–15(17) × (20)26–33(35) | (1)1.5(2) | 8 | bizonate | oblong-ellipsoidal | Cummins (1975) | ||||
| R. rata | – | – | – | – | – | – | – | Hennen et al. (2005) | ||||
| R. roemerianae | intrasoral | clavate | 10–14 × 27–38 | 1–1.5 | 8 | bizonate | obovoidal-oblong | Long (1917) | ||||
| R. scopulata | not stated | clavate | (17)19–24 × (11)12–14(15) | (1)1.5(2) | 6–8 | bizonate | oblong-ellipsoidal | Cummins and Baxter (1976) | ||||
| R. stevensii | peripheral | clavate - capitate | 8–13 × 25–30 | <1 | 4 | equatorial | oblong-obovoidal | Arthur (1915) | ||||
| R. transvaalensis | – | – | – | – | – | – | – | Doidge (1939) | ||||
| R. versatilis | intrasoral | clavate - capitate | 13–18 × 26–32 | Not stated | 8 | bizonate | obovoidal-oblong | Dietel (1894) | ||||
The resemblance of teliospore characters in R.cohniana and the species identified in the present study suggests a close relationship which is supported by the phylogenetic reconstructions. These neotropical rusts on Senegalia further appear to have evolved independently from those Senegalia rusts that have a paleotropic origin (Fig. 1, Table 1). The phylogenetic distinction of both lineages is also mirrored by a morphological feature: the arrangement of teliosporic cysts is uniseriate in the analysed neotropic species but multiseriate in all investigated paleotropic Senegalia rusts (Table 2).
Key to species of Ravenelia infecting neotropical Senegalia trees
| 1 | Teliospores ≤64 mm; urediniospores with equatorially arranged germ pores | 2 |
| – | Teliospores >64 mm; urediniospores with bizonate or equatorially arranged germ pores | 4 |
| 2 | Paraphyses present in uredinia | 3 |
| – | Paraphyses absent in uredinia | R. rata |
| 3 | Teliospores with <6 verrucae per cell; on S.riparia | R. stevensii |
| – | Teliospores with 6–20 spines per cell; on S.glomerosa | R. lata |
| 4 | Urediniospores with 6–8 bizonate germ pores; teliospores verrucose or smooth | 5 |
| – | Urediniospores if present with equatorially arranged germ pores; teliosporesspinescent or verrucose; teliospore cysts uniseriate | 8 |
| 5 | Teliospores smooth | 6 |
| – | Teliospores verrucose | 7 |
| 6 | On S.anisophylla; urediniospores 12–14 × 19–24 mm | R. versatilis |
| – | On S.greggii; urediniospores 13–18 × 26–32 mm | R. scopulata |
| 7 | With intrasoral paraphyses; on S.roemeriana | R. roemerianae |
| – | On S.greggii | R. pringlei |
| 8 | Paraphyses present; teliospores verrucose; on S.bonariensis | R. monosticha |
| – | Paraphyses absent; teliospores spinescent | 9 |
| 9 | Teliospores with 7–11 spines per cell; urediniospores often limoniform; on S.hayesii | R. piepenbringiae |
| – | Teliospores with 3–5 spines per cell; urediniospores obovoidal to ellipsoidal,sometimes limoniform | 10 |
| 10 | Teliospores 59–96 mm in diameter; urediniospores <13mm in width; urediniospore wall laterally 1–1.5 mm; on S.tenuifolia | R. hernandezii |
| – | Teliospores 39–75 mm in diameter; urediniospores 11–19 mm in width; urediniospore wall laterally 1.5–2.5 mm; on S.praecox | R. cohniana |
Supplementary Material
Acknowledgements
We gratefully acknowledge Dr. Meike Piepenbring, the US National Fungus Collections (USDA-ARS) and the South African Mycology Collections (PREM) for providing herbarium specimens on loan. We also wish to thank Katharina Görges for providing drawings of the urediniospores of R.piepenbringia and R.hernandezii.
Citation
Ebinghaus M, Begerow D (2018) Ravenelia piepenbringiae and Ravenelia hernandezii, two new rust species on Senegalia (Fabaceae, Mimosoideae) from Panama and Costa Rica. MycoKeys 41: 51–63. https://doi.org/10.3897/mycokeys.41.27694
References
- Aime C. (2006) Toward resolving family-level relationships in rust fungi (Uredinales). Mycoscience 47: 112–122. 10.1007/S10267-006-0281-0 [DOI] [Google Scholar]
- Berndt R. (2004) A checklist of Costa Rican rust fungi. In: Agerer R, Piepenbring M, Blanz P. (Eds) Frontiers in Basidiomycete Mycology.IHW Verlag, München, 185–236 .
- Cummins GB, Hiratsuka Y. (2003) Illustrated Genera of Rust Fungi (3rd edn). Phytopathological Society, St. Paul, MN, APS Press, St. Paul, MN.
- Dianese JC, Medeiros RB, Santos LTP, Furlanetto C, Sanchez M, Dianese AC. (1993) Batistopsora gen. nov. and new Phakopsora, Ravenelia, Cerotellium, and Skierka species from the Brazilian Cerrado. Fitopatologia Brasileira 18: 436–450. [Google Scholar]
- Farr DF, Rossman AY. (2015) Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. http://nt.ars-grin.gov/fungaldatabases [Accessed 17 December 2015]
- Hennen JF, Figueiredo MB, de Carvalho Jr AA, Hennnen PG. (2005) Catalogue of the species of plant rust fungi (Uredinales) of Brazil. Instituto de Pesquisas, Jardim Botanico do Rio de Janeiro: Rio de Janeiro, Brazil.
- Hennings P. (1896) Beiträge zur Pilzflora Südamerikas I. Myxomycetes, Phycomycetes, Ustilagineae und Uredineae. Hedwigia 35: 246.
- Hernández JR, Hennen JF. (2002) The Genus Ravenelia in Argentina. Mycological Research 106: 954–974. 10.1017/S0953756202006226 [DOI] [Google Scholar]
- Katoh K, Standley DM. (2013) MAFFT multiple sequence alignment software version 7: improvements in performance and usability. Molecular Biology and Evolution 30: 772–780. 10.1093/molbev/mst010 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moncalvo JM, Wang HH, Hseu RS. (1995) Phylogenetic relationships in Ganoderma inferred from the internal transcribed spacers and 25S ribosomal DNA sequences. Mycologia 87: 223–238. 10.1080/00275514.1995.12026524 [DOI] [Google Scholar]
- Piepenbring M. (2006) Checklist of fungi in Panama. Puente Biológico Volume 1: 1–190. [Google Scholar]
- Rambaut A. (2009) FigTree, a graphical viewer of phylogenetic trees. http://tree.bio.ed.ac.uk/software/figtree
- Rezende DV, Dianese JC. (2001) New Ravenelia species on leguminous hosts from the Brazilian Cerrado. Fitopatologia Brasileira 26: 627–634. 10.1590/S0100-41582001000300008 [DOI] [Google Scholar]
- Rodriguez FJ, Oliver JL, Marín A, Medina JR. (1990) The general stochastic model of nucleotide substitution. Journal of Theoretical Biology 142: 485–501. 10.1016/S0022-5193(05)80104-3 [DOI] [PubMed] [Google Scholar]
- Scholler M, Aime C. (2006) On some rust fungi (Uredinales) collected in an Acaciakoa–Metrosiderospolymorpha woodland, Mauna Loa Road, Big Island, Hawaii. MycoScience 47: 159–165. 10.1007/S10267-006-0286-8 [DOI] [Google Scholar]
- Silvestro D, Michalakis I. (2012) raxmlGUI: a graphical front-end for RAxML. Organisms Diversity and Evolution 12: 335–337. doi: 10.1007/s1127-011-0056-0 [DOI] [Google Scholar]
- Spegazzini CL. (1909) Mycetes Argentinenses. Anales del Museo Nacional de Buenos Aires. Series. 3, 12: 296.
- Stamatakis A. (2014) RAxML version 8: a tool for phylogenetic analysis and post-analysis of large phylogenies. Bioinformatics 30: 1312–1313. 10.1093/bioinformatics/btu033 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sydow H, Sydow P. (1916) Fungi amazonici a cl. E. Ule lecti. Annales Mycologici 14: 65–97. [Google Scholar]
- Tamura K, Stecher G, Peterson D, Filipski A, Kumar S. (2013) MEGA6: Molecular Evolutionary Genetics Analysis version 6.0. Molecular Biology and Evolution 30: 2725–2729. 10.1093/molbev/mst197 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vilgalys R, Hester M. (1990) Rapid genetic identification and mapping of enzymatically amplified ribosomal DNA from several Cryptococcus species. Journal of Bacteriology 172: 4238–4246. 10.1128/jb.172.8.4238-4246.1990 [DOI] [PMC free article] [PubMed] [Google Scholar]
- White TJ, Bruns T, Lee S, Taylor JW. (1990) Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis MA, Gelfand DH, Sninsky JJ, White TJ. (Eds) PCR Protocols: A Guide to Methods and Applications.Academic Press, Inc., New York, 315–324.
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.