Macrophomina euphorbiicola

Macrophomina euphorbiicola A.R. Machado, D.J. Soares & O.L. Pereira, Eur. J. Pl. Path. 153: 96 (2018) Figure 1.

Index Fungorum number: IF815562.

Saprobic on dead seeds of Plukenetia volubilis L. Sexual morph: Not observed. Asexual morph: Conidiomata 116–172 × 130–161 μm (x̅ = 137 × 149 μm, n = 20), circular, dark brown to black, solitary or gregarious, immersed through the epidermis, visible as black dots or papilla on the host, glabrous. Peridium up to 11–24 μm wide, composed of dark brown to black thick-walled textura angularis, becoming thin-walled and hyaline towards the inner region. Ostiole 12–32 μm diam., cylindrical, short, straight, centrally or laterally located. Paraphyses absent. Conidiophores subcylindrical to ampulliform, reduced to conidiogenous cells. Conidiogenous cells 6–14 × 2–5 μm (x̅ = 9 × 3 μm, n = 20), terminal, hyaline, cylindrical to ellipsoidal, smooth-walled. Conidia 22–26 × 8–11 μm (x̅ = 23 × 9 μm, n = 50), hyaline, oblong to cylindrical, with rounded apex, and narrow, straight, frequently constricted in the middle, aseptate, contents granular, thick- and smooth-walled, bearing octagonal beard-shaped appendages, or widely flared or irregular, undulate, mucoid apical appendage, basal appendages absent.

Culture characteristics: Conidia germinating on PDA within 12 h with germ tubes produced from the middle or each end. Colonies are fast growing on PDA, reaching 90 mm diam. after 5–6 days at 20–23 °C. Sparse, aerial, filamentous, after 2 weeks, becoming dark brown to black.

Material examined: Thailand, Chiang Rai Province, Thoeng, Tambon Nang Lae, Rai Ruen Rom Organic Farm, 19°39’30.2’’ N, 100°09’26.4’’ E, on dead seeds of Plukenetia volubilis L., 11 June 2019, Na Wu, YW62 (MFLU 23-0004), living culture MFLUCC 23-0057.

Notes: Macrophomina euphorbiicola was introduced by Machado et al. [43]. Due to the previous cultures failing to sporulate, comparison with the type species was not possible. The phylogenetic analysis showed that our isolate was nested within M. euphorbiicola and claded closer to M. pseudophaseolina (Figure 1). We, thus, identify the new collection as M. euphorbiicola.