Diplodia parva S.Y. Lee, L.N. Ten & H.Y. Jung, 2021

Lee, Seung-Yeol, Ten, Leonid N., Ayim, Benjamin Yaw, Fulbert, Okouma Nguia, Das, Kallol & Jung, Hee-Young, 2021, Diplodia parva sp. nov., a novel species of the family Botryosphaeriaceae isolated from soil in Korea, Phytotaxa 514 (2), pp. 105-117 : 107-109

Diplodia parva S.Y. Lee, L.N. Ten & H.Y. Jung sp. nov. ( FIGURE 2 )

MycoBank: MB834635

Etymology: The specific epithet is derived from the Latin word parva (“small”), and refers to the small conidia size.

Typus: The culture was isolated from soil in Dongducheon , Korea (37°55’25.5”N, 127°02’49.8”E). The stock culture ( NIBRFG0000499836 ) was deposited in the National Institute of Biological Resources ( NIBR), metabolically inactive culture .

*Ex-type (ex-epitype) strains

The isolated strain is shown in bold

Habitat: The species was found in soil. The soil was a yellowish-brown, fine gravelly clay loam, with a low moisture capacity.

Description: The average diameters of colonies on PDA and MEA were 73.8 mm and 64.9 mm, respectively, after three days of incubation at 25 °C. The growth of mycelial colonies was round, and there were also variations in the diameter of the colonies across the different media ( FIGURE 2 ). On MEA, white mycelium developed and turned dark gray; the reverse color was pale brown to dark brown at the center. On PDA, initially floccose white to brown mycelium developed and turned black after three days at 25 °C. Conidiomata were pycnidial, globose, immersed, unilocular, and dark brown to black; the ostiole was single, central, and circular; the conidiomata wall was brown to dark brown. Conidiophores reduced to conidiogenous cells. Conidiogenous cells were hyaline, subcylindrical to cylindrical, and smooth, arising from the inner wall of the locule. Conidia were oblong to clavate, oval, round and with a blunt edge apex, aseptate with a smooth thick wall, of a size in the range of 22.7– 29.3 μm × 8.9–10.9 μm, hyaline became yellowish to dark brown (n=100). Sometimes the wall edge was dark yellow ( FIGURE 2 ).

Notes: Morphologically, strain KNU16-007 resembles the phylogenetically closely related D. sapinea , Diplodia intermedia A.J.L. Phillips, J. Lopes & A. Alves , D. scrobiculata , D. seriata , Diplodia rosacearum S. Giambra, A. Alves, J. Armengol & S. Burruano , Diplodia crataegicola Dissanayake, Camporesi & K.D. Hyde , and Diplodia citricarpa Abdollahz. & Crous , but the novel species is readily distinguishable from them by its conidia shape and size ( Table 2). The average size of the conidia of strain KNU16-007 (26.0 μm × 9.9 μm) is much shorter than that of D. sapinea (41.5 μm × 16.3 μm), D. scrobiculata (39.5 μm × 14.0 μm), and D. intermedia (31.3 μm × 13.5 μm). The average conidia length of strain KNU16-007 is significantly longer than that of D. crataegicola (14 μm), and slightly longer than that of D. citricarpa (23.5 μm), D. rosacearum (23.7 μm), and D. seriata (24.5 μm). However, the width of its conidia is much shorter than that of D. seriata (13.0 μm) and D. rosacearum (12.8 μm). The conidial length:width ratio clearly differentiates strain KNU16-007 (2.63) from D. crataegicola (1.55), D. seriata (1.88), and D. rosacearum (1.9). Finally, in contrast to D. citricarpa and D. rosacearum , conidia of KNU16-007 do not become 1-septate with age.

Figures

FIGURE 2. Cultural and morphological characteristics of Diplodia parva KNU16-007. A, B and C, pycnidia on pine needle; D, conidiophore; E, front and reverse view of the colony on PDA; F, front and reverse view of the colony on MEA; G, conidiogenous cells; H, conidia. Scale bars:A, B = 100 µm; C, D, G, H = 10 µm.