Alternaria hedjaroudei Y. Ghosta, E. Hashemlou, A. Poursafar & R. Azizi, 2020

Hashemlou, Esmaeil, Ghosta, Youbert, Poursafar, Alireza & Azizi, Razmig, 2020, Morphological and molecular identification of Alternaria hedjaroudei sp. nov., a new species in section Panax from Iran, Phytotaxa 438 (2), pp. 130-140 : 134-138

Alternaria hedjaroudei Y. Ghosta, E. Hashemlou, A. Poursafar & R. Azizi sp. nov. ( Figs. 2 , 3 )

MycoBank No.: MB 831884

Type:— Iran, West Azarbaijan Province: Urmia, Marmishu, 37°37’11.6” N, 44°43’00.2” E, 1567 m a.s.l., isolated from overwintered stems of Serratula coriacea , 25 April 2017. Esmaeil Hashemlou (Holotype: IRAN 17111 F, ex-type culture: IRAN 3241 C) ; GenBank accession numbers: MH678652 ( ITS), MH678650 ( GAPDH), MH678656 ( RPB2 ), MH678654 ( TEF) .

Etymology:—The specific epithet is proposed in honor of Prof. Ghorbanali Hedjaroude, a distinguished mycologist in Iran.

Saprobic on overwintered stems of Serratula coriacea . Sexual morph: Ascomata are formed frequently after 2 months incubation at 4 ºC on PCA culture media and fully matured after 3 months ( Fig. 3a–c ). They are scattered or rarely aggregated, usually formed on the surface of or rarely embedded in culture medium, subglobose, with dark and relatively thick-walled at maturity, textura angularis, 200‒380 µm diam. ( Fig. 3d–e ). Asci are bitunicate, cylindrical, straight or slightly curved, with round apex, 90–120(–125) × 14–17 µm, 8-spored ( Fig. 3f–j ). Pseudoparaphyses hyphoid, septate, 60‒140 × 2‒3 µm ( Fig. 3k ). Ascospores are mainly formed in two rows. Juvenile ascospores are fusoid or ellipsoid. Fully developed ascospores are ellipsoid with the distal cell broadly round than the basal cell; the terminal cells of the ascospores usually remain aseptate, but in rare cases a single longitudinal septum is formed in broadly round distal cell, 4–5 transverse septa and 1(–2) series of longitudinal septa in the central segments, conspicuously constricted at the median transverse septum, mostly inequilateral, 18–28 × 8–10 µm. Ascospores are light brown to brown with darker septa ( Fig. 3l–y ). Asexual morph: Sporulation on the substrate surface of PCA colony is scant and inconspicuous, instead is abundant on branches throughout the aerial growth. Primary conidiophores arising singly, laterally or terminally from aerial hyphae, smooth-walled, simple or rarely branched, light to medium brown, 3–10- septate, straight or somewhat curved, 1–4-geniculate, 30–145 × 4–6 μm ( Fig. 2e–l ). Juvenile conidia are ovoid or ellipsoid. Mature conidia are ovoid, ellipsoid to long ellipsoid, obclavate and laterally symmetrical, however, in a large number of conidia, several cells are markedly swollen and conidia become variously asymmetrical. Conidia are mostly produced singly, they are beakless, except for short to moderately long apical secondary conidiophores (5–40 × 3–5 μm) that function in the formation of simple chains of 2(–3) conidia. The outer wall is smooth, conspicuously constricted at most of their transverse septa. Small sized conidia are 14–28 × 8–16 µm, with 1–4 transverse, and 1 longitudinal septum in some of the transverse segments; medium sized conidia are 28–41 × 8–17 µm, with 3–7 transverse, and 1–2 longitudinal septa in some of the transverse segments and large sized conidia are 42–68 × 11–20(– 28) µm, with 4–9 transverse, and 1–3 longitudinal septa in some of the transverse segments. Conidia are light brown to brown ( Fig. 2m –z ).

Culture characteristics:— Colonies after 7 days at 25 ºC and 8/16 h fluorescent light/dark cycle: on PDA flat, cottony, white to smoke gray, 75 mm diam ( Fig. 2a ); on PCA flat, cottony, olivaceous grey to dark mouse gray, with white aerial hyphae at center, 75 mm diam ( Fig. 2b ); on HA flat, cottony, greenish olivaceous, with white aerial hyphae at center ( Fig. 2c ), 74 mm diam, and on V 8– A flat, felty, iron gray at center, and light brown at margins, 72 mm diam ( Fig. 2d ). Almost entire colony consists of an open wooly and arachnoid aerial long ascending single or funiculus hyphae.

Additional specimens examined:— Iran, West Azarbaijan Province: Urmia , Marmishu, 37°37’7.9”N, 44°42’50.7”E, 1591 m a.s.l., isolated from overwintered stems of Serratula coriacea , 29 March 2018, IRAN 3242 C, GenBank accession numbers: MH678653 ( ITS), MH678651 ( GAPDH), MH678657 ( RPB2 ), MH678655 ( TEF) ; collected by Esmaeil Hashemlou, and at 37°40’39.7” N, 44°59’14.5”, 1340 m a.s.l., isolated from overwintered stems of Serratula coriacea , 12 April 2018, IRAN 3243 C, collected by Youbert Ghosta.

Notes:— Alternaria hedjaroudei is phylogenetically close to, but different from A. avenicola , A. calycipyricola and A. photistica . Growth of Alternaria avenicola on PCA is completely mycelial and there is no sporulation within 7 days on undisturbed PCA colonies ( Simmons 2007). Conidia of A. avenicola has longer conidium body (80–90 µm on scraped or cut PCA and 70–100 µm on V 8– A vs. 14–68 µm in A. hedjaroudei on PCA and 23‒80 on V 8– A). Moreover, formation of abundant thick-walled chlamydospores mostly in chains or clusters in A. avenicola and its larger ascomata (300–600 µm vs. 200–380 µm in A. hedjaroudei ) ( Kwaśna & Kosiak 2003) can be used to distinguish the two species. Alternaria calycipyricola has slower growth rate on V 8– A than A. hedjaroudei and sporulates as relatively short chains of 2–7 conidia and with longer secondary conidiophores (up to 100 µm) compared to A. hedjaroudei with mostly solitary conidia, rarely with chains of only 2–3 conidia and shorter secondary conidiophores (up to 40 µm) ( Roberts 2007, Simmons 2007). Alternaria photistica sporulates as relatively short chains of 3–6 conidia or in loose clumps of branched chains (16–20 conidia per clump) and has more transverse septa in mature ascospores (6–7 vs. 4–5 in A. hedjaroudei ) ( Simmons 1986, 2007).

Figures

FIGURE 2. Alternaria hedjaroudei. a-d, Colonies after 7 days on PDA (a), PCA (b), HA (c), and V8–A (d). e–f, Sporulation pattern. g–l, Primary conidiophores. m–o, Secondary conidiophores. p–z, Conidia. Scale bars 25 µm.

FIGURE 3. Alternaria hedjaroudei. a–c, Ascomata formed on PCA culture medium. d–e, Ascomata wall. f–g, Hymenium. h–j, 8-spored mature asci. k, Pseudoparaphyses. l–z, Ascospores. Scale bars 20 µm.