Phyllactinia braunii Kushwaha, Raghv. Singh, Chaurasia & Sham. Kumar, 2017

Kushwaha, Prakash, Singh, Raghvendra, Chaurasia, Balmukund & Kumar, Shambhu, 2017, Phyllactinia braunii sp. nov. (Erysiphales) on Cordia myxa from Central India, Phytotaxa 305 (3), pp. 140-148 : 144-145

Phyllactinia braunii Kushwaha, Raghv. Singh, Chaurasia & Sham. Kumar , sp. nov. ( Figs. 1–7 )

MycoBank: MB816178

Diagnosis:— Morphologically similar to Phyllactinia thirumalachari , but the conidiophores (100–240 × 7–12 μm), non-catenate conidia (49.4–83.6 × 15.2–26.6 μm), chasmothecia (190–342 μm diam.), asci (68–95 × 27–34 μm) 2–3-spored, and ascospores (23–42 × 15–23 μm) of P. thirumalachari are longer.

Etymology:— Latin, braunii is derived from Uwe Braun (Martin Luther University, Halle (Saale), Germany), the renowned mycologist and monographer of Erysiphales .

Type:— INDIA. Madhya Pradesh: Chhatarpur Forest, on living leaves of Cordia myxa L. (Boraginaceae), March 2014, coll. Prakash Kushwaha, holotype (AMH 9672), isotype (MH-DHSGU 16).

Colonies hypophyllous, effuse, white, powdery, at first forming regular or irregular patches on the leaf surface, but later coalescing to become irregular and spreading over the entire lower leaf surface. Mycelium external, superficial. Hyphae hyaline, branched, septate, 0.5–1.25 μm wide. Conidiophores macronematous, arising singly as lateral branches of hyphae, unbranched, erect to procumbent, straight to flexuous, cylindrical, hyaline, smooth, thin-walled, 1–4-septate, 30–50 × 1–2.5 μm, foot cell cylindrical, 4–20 × 0.5–4.5 μm. Conidiogenous cells integrated, terminal. Conidia acrogenous, formed singly, sometimes catenate, hyaline, thin-walled, aseptate, clavate, rhomboid, or sometimes fusiform, apex rounded, 26–44 × 6.5–9.5 μm, germinating conidia observed. Ascomata (chasmothecia) hypophyllous, scattered to sub-gregarious, globose to subglobose, initially hyaline to light yellowish, later becoming reddish brown to blackish brown, 110–135 μm diam. Peridial cells obscure, irregularly polygonal. Appendages10–18 per ascoma, thick-walled, hyaline to olivaceous, aseptate, smooth, unbranched, straight, arising from the equatorial zone of the ascoma and radially elongated outward, apex acute, 45–155 × 2.5–7.5 μm, base swollen or bulbous, 12–22 μm diam. Penicillate cells numerous, covering almost the whole surface of ascomata at maturity, stems 8–12 × 4–6 μm, divided at the apex into several very short branches or filaments, 8–21 × 0.5–2.5 μm, tips of filaments swollen, filaments 1–2 times longer than the stem. Asci numerous, short stalked, hyaline to mid olivaceous, thin-walled, smooth, 40–55 × 17–25 μm, containing(1–)2 ascospores. Ascospores ellipsoid to ovoid, sometimes fusiform, hyaline to olivaceous, smooth, thin-walled, aseptate, 20–32 × 16–20 μm, with dense cytoplasm containing yellowish oil like droplets.

Figures

FIGURE 1. Symptoms on Cordia myxa a. Infected host plant. b. Early stage of infection showing powdery appearance. c–e. Late stage of infection with developed cleistothecia. Scale bars: b–d = 15 mm, e = 5 mm.

FIGURE 2. Microphotographs of anamorph of Phyllactinia braunii (AMH 9672, holotype). a–f. Conidia. g. Germinating conidium. h–i. Conidiophores. Scale bars: a = 10 μm, b–i = 20 μm (red arrow for germinated conidium and green arrows for catenate conidia).

FIGURE 3. Microphotographs of Phyllactinia braunii (AMH 9672, holotype).a–b.Initial stage of developingchasmothecia (homogenious cells). c–f. Developing chasmothecia (differentiating cells). g. Fully developed chasmothecium. h–k. Appendages of chasmothecia. l–m Ruptured chasmothecia. n–p. Asci with ascospores. Scale bars: a–b = 20 μm, c–p = 25 μm.

FIGURE 4. Microphotographs of mature chasmothecia of Phyllactinia braunii (AMH 9672, holotype). a. Heavily infected leaf with fully matured chasmothecia. b–d. Mature chasmothecia with several very short filaments of penicillate cells.Arrows show stems of penicillate cells divided at the apex into several very short filaments. Scale bars: a = 15 mm, b–d = 25 μm.

FIGURE 5. Drawings of anamorph of Phyllactinia braunii (AMH 9672, holotype). Conidiophores with conidia. Scale bar: = 50 μm.

FIGURE 6. Drawings of Phyllactinia braunii (AMH 9672, holotype) a. Initial stage of developing chasmothecium (homogenious cells). b. Developing chasmothecium (differentiation of cells). c–d. Fully developed chasmothecium. e. Ruptured chasmothecium with ascus and ascospores. Scale bars: a–c = 50 μm, d–e = 25 μm.

FIGURE 7. SEM characteristics of Phyllactinia braunii (AMH 9672, holotype) a–e. Conida. f–g. Conidia with conidiophores. h. Chasmothecium. i. Fully developed chasmothecium with penicillate cells with several very short branches or filaments. Scale bars: a–g = 10 μm, h–i = 100 μm.