Puccinia doidgeae Tabé, Aime & M. Piepenbr., 2022

Tabe, Affoussatou, Aime, M. Catherine, Yorou, Nourou Soulemane & Piepenbring, Meike, 2022, New records and data on rust fungi (Pucciniales, Basidiomycota) in Benin, Phytotaxa 548 (2), pp. 127-145 : 134-136

Puccinia doidgeae Tabé, Aime & M. Piepenbr. , nom. nov., stat. nov.

MycoBank: 841915

Figures 6–7

Replaced synonym: Puccinia canaliculata var. tenuis Doidge, Bothalia 4: 900 (1948). Type: On Cyperus esculentus L., SOUTH AFRICA. Brits, Hartbeespoort, (no date), F. M. du Toit 33120 (type probably in PREM, n.v., not available upon request). [non Puccinia tenuis (Schwein.) Burrill 1884 ]

Etymology: —Honouring Ethel Mary Doidge, who noticed that this taxon is distinct from typical Puccinia canaliculata .

Uredinia amphigenous, more abundant on the abaxial side of the leaves, elongated, parallel to the veins of the leaves, first subepidermal, later erumpent, orange-brown, containing only urediniospores or sometimes mixed with teliospores. Urediniospores broadly ellipsoidal, globose, or pyriform, (22–)24–28(–30) × (16–)18–22(–24) µm (n = 33), yellow to pale yellow, finely echinulate, golden brown, wall 2 µm thick, with 2 equatorial germ pores, pedicels hyaline, mostly 60–70 µm long. Urediniospores easily break off the pedicels, so urediniospores with pedicels attached to them are rarely observed. After the liberation of numerous urediniospores, a uredinium presents a ‘cushion’ formed by disused pedicels. Telia abaxial, elongated between veins of the leaves, usually 0.5–1 mm long, rarely up to 2 mm, approximately 200 µm broad, subepidermal, black, with teliospores in locules, delimited by pseudoparaphyses evident in transverse sections observed by light microscopy. Pseudoparaphyses densely packed, more or less curved, 50–80 µm long and 1–3 µm broad, slightly enlarged (up to 5 µm) at the tips, light brown. Teliospores clavate, not or slightly constricted at the septa, apex acuminate or rounded, two-celled, (40–)43–55(–70) × (12–)13–16(–17) µm (n = 20), yellowish brown, more strongly pigmented towards the tips, wall 1–1.5 µm thick at the sides, 6–7(–9) µm thick at the apex, pedicels reddish brown, pigmentation darker than at the tips of the teliospores, up to 45 µm long (n = 10).

Sequence data of the 28S ribosomal DNA indicate that P. canaliculata var. tenuis is not conspecific with other specimens of P. canaliculata ( Fig. 8 ). Therefore and because of morphological differences (see below), we propose to raise the variety to species rank. As the name at the new rank, Puccinia tenuis , is occupied by the name P. tenuis (Schwein.) Burrill , we propose to replace it by the new name P. doidgeae .

Host and distribution in Benin: —Uredinia and telia on Cyperus esculentus (Cyperaceae) , Northwestern Benin.

Specimen examined: — Uredinia and telia on Cyperus esculentus : BENIN. Atacora: Boukoumbé, Koutatiégou village , Koussogou hamlet, elev. 234 m, 10°11’ N, 1°05’ E, 15 September 2019, M . Piepenbring , M. U . Schmidt , and participants of the symposium 2019, MP5444 (= TA430 ) ( UNIPAR), GenBank Acc. no. LSU: OL 437033 , ITS: OL 437018 .

Specimens examined for comparison: — Puccinia canaliculata (Schwein.) Lagerh. on Cyperus rotundus L.: BENIN. Borgou: Parakou, around Campus of the University of Parakou, elev. 356 m, 9°20’ N, 2°38’ E, 15 September 2019, A. Tabé, Y. Meswaet, R. Dramani, TA427 (UNIPAR), GenBank Acc. no. LSU: OL437027 . On the same host plant with spikelets of different colour, at the same locality, elev. 356 m, 9°20’ N, 2°38’ E, 15 September 2019, A. Tabé, Y. Meswaet, R. Dramani, TA436 (UNIPAR), GenBank Acc. no. LSU: OL437028 , ITS: OL437017 . These two specimens only present uredinia and were identified as P. canaliculata based on molecular sequence data ( Fig. 8 ).

Host species of P. doidgeae : —Primary host species: Cyperus esculentus , Cyperus sp. (Cyperaceae) ( Doidge 1948, Viennot-Bourgin 1959). Secondary host species: not known.

Distribution: —Africa [ Guinea ( Viennot-Bourgin 1959), South Africa ( Doidge 1948)]. This species has not been reported outside Africa and is reported here for the first time for Benin. Specimens of P. doidgeae probably have been identified as P. canaliculata in the past.

Comments: —According to the key for the identification of species of Puccinia infecting Cyperus spp. ( Kern 1919) , the specimen from Benin represents P. canaliculata , due to urediniospores with two equatorial germ pores and walls uniformly 1–2 µm thick. In addition, P. canaliculata differs from P. cyperi Arthur by the presence of loculate telia, that have also been referred to as telia with stroma. The specimen from Benin, however, differs from P. canaliculata by slenderer teliospores (13–16 µm wide) versus 15–21 µm ( Kern 1919) and 14–22 µm ( Barreto & Evans 1995) for typical teliospores of P. canaliculata . Based on this difference, Doidge (1948) established the new variety, P. canaliculata var. tenuis , that was later confirmed by Viennot-Bourgin (1959).

Figures

FIGURE 6. Puccinia doidgeae on Cyperus esculentus (MP5444). A Abaxial uredinia and telia B orange-brown, erumpent uredinia, black embedded telia, and whitish to orange young sori.

FIGURE 7. Puccinia doidgeae on Cyperus esculentus (MP5444). A Part of a uredinium with ruptured host tissue, numerous pedicels, and some urediniospores in various developmental stages B mature urediniospores with germ pores drawn in surface view or in optical sections C teliospores with pigmented pedicels and slightly pigmented tips D a telium with two locules delimited by pseudoparaphyses, filled with teliospores, and surrounded by host tissue. Dots of different density indicate more or less strong pigmentation. Scale bars: 10 µm (A, D); 5 µm (B, C).

FIGURE 8. RAxML analysis of 28S rDNA sequences of Puccinia spp. mostly on species of Cyperaceae. Sequences newly generated for this study are indicated in bold. RAxML bootstrap support>70 is indicated next to supported node.