Fuscosphaeria hungarica D.G. Knapp & Pintye, gen. et sp. nov. (Figs. 2, 4)

MycoBank number: MB 835598; Index Fungorum number: IF 835598; Facesoffungi number: FoF 11765;

Typification: HUNGARY. KISKUNSÁG: semiarid sandy open grassland near Fülöpháza, N46° 52′ E19° 25′, in root of Festuca vaginata, 22 Apr 2014, D.G. Knapp DSE883 (CBS 147250) (holotype 111139BP). GenBank: ITS = MW20 9054; LSU = MW209 059; SSU = MW209065; TEF = MW238843; RPB1 = MW238822; TUB = MW238825.

Etymology: Fusco (from the Latin word fuscus, meaning dark, swarthy) + sphaeria (from the Greek word sphairion, diminutive of sphaira, meaning ball, sphere, referring to its pigmented ascomata-like structures). The species was named “hungarica” because its occurrence solely in one semiarid Hungarian grassland. Fuscosphaeria hungarica differs from one of its closest phylogenetic neighbors Trematosphaeria pertusa CBS 122368, the ex-type strain of the type species of Trematosphaeria (Treamatosphaeriaceae), by its unique fixed alleles in the LSU, SSU, and TEF loci, which was found based on the alignments of separate loci deposited in TreeBASE as study S26261: LSU positions: 54 (T), 61 (C), 62 (C), 63 (G), 64 (T), 67–70 (deletion), 172 (A), 181 (T), 197 (T), 204 (C), 216 (A), 235 (T), 237 (T), 337 (G), 383 (T), 386 (C), 387 (T), 389 (C), 391 (T), 392 (A), 401 (T), 408 (dele-tion), 412 (T), 414–415 (deletion), 429 (C), 430 (G), 446 (T), 449 (G), 468 (C), 474 (G), 476 (C), 479 (deletion), 481 (T), 484 (T), 486 (G), 497 (A), 537 (C), 545 (G), 547 (T), 553 (C), 561 (deletion), 564 (T), 571 (A), 578 (C), 582 (C), 663 (A), 669 (A), 674 (A), 690 (G), 708 (T), 709 (C), 710–720 (deletion), 724 (T); SSU positions: 116 (C), 120 (A), 128 (G), 133 (G), 159 (G), 160 (C), 160 (C), 162 (C), 164 (T), 165 (T), 166 (C), 167 (G), 168 (G), 169 (G), 187 (G), 198 (G), 206 (T), 263 (A), 273 (T), 293 (G), 296 (G), 313 (G), 317 (C), 324 (G), 335 (A), 343 (C), 378 (C), 383 (C), 395 (G), 398 (G), 506 (G), 507 (A), 508 (C), 509 (A), 510 (T), 511 (T), 512 (C), 513 (A), 515 (C), 517 (C), 523 (A), 524 (T), 539 (A), 540 (G), 545 (T), 553 (C), 554 (C), 555 (T), 556 (C), 557 (G), 558 (C), 560 (A), 562 (C), 563 (G), 564 (C), 566 (G), 568 (G), 572 (T), 573 (T), 575 (C), 583 (A), 597 (C), 598 (T), 601 (G), 623 (A), 641 (G), 642 (A), 653 (A), 654 (T), 655 (C), 656 (G), 660 (A), 662 (G), 663 (A), 664 (T), 673 (A), 675 (T), 689 (G), 691 (C), 692 (A), 693 (C), 705 (T), 711 (A), 728 (G), 729 (T), 740 (C), 748 (C), 779 (A), 780 (T), 793 (C), 801 (A), 817 (C), 831 (G), 834 (C), 839 (G), 841 (deletion), 912 (deletion), 918 (deletion), 920 (T), 923 (T), 924 (T), 939 (G), 941 (G), 990 (G), 991 (G), 992 (A), 993 (G), 994 (T), 995 (C), 996 (G), 997 (C), 998 (G), 999 (C), 1000 (T), 1001 (T), 1002 (C), 1003 (G), 1004 (C), 1005 (A), 1009 (G), 1012 (C), 1023 (G), 1024 (A), 1025 (A), 1034 (T), 1035 (T), 1037 (T), 1038 (C), 1040 (C), 1043 (G), 1044– 1045 (deletion), 1051 (C), 1052 (C), 1055 (A), 1056 (A), 1057 (A), 1059 (A), 1196 (T), 1197 (C), 1222 (deletion), 1223 (G), 1316 (G), 1326 (T), 1329 (G), 1332 (C), 1333 (T), 1388 (A), 1424 (T), 1425 (T), 1454 (T); TEF positions: 24 (C), 30 (G), 37 (C), 55 (T), 91 (C), 94 (C), 115 (G), 116 (A), 118 (G), 127 (C), 133 (T), 152 (A), 169 (G), 172 (C), 174 (T), 176 (C), 178 (C), 184 (C), 190 (A), 196 (G), 208 (T), 217 (T), 220 (A), 226 (C), 241 (A), 250 (C), 256 (C), 263 (A), 283 (G), 284 (C), 289 (G), 290 (A), 331 (G), 334 (C), 338 (T), 339 (C), 341 (T), 343 (T), 352 (T), 355 (G), 358 (C), 361 (A), 364 (C), 367 (T), 372 (G), 386 (A), 394 (C), 397 (T), 409 (C), 415 (A), 418 (C), 421 (T), 439 (C), 448 (C), 454 (G), 483 (C), 491 (T), 493 (C), 511 (C), 517 (T), 538 (A), 544 (C), 562 (G), 569 (A), 570 (C), 571 (T), 572 (G), 578 (C), 580 (C), 589 (T), 607 (T), 619 (C), 634 (T), 637 (C), 643 (T), 649 (T), 652 (T), 655 (T), 673 (T), 685 (C), 688 (A), 712 (T), 715 (C), 733 (G), 745 (T), 769 (T), 778 (T), 781 (T), 793 (T), 802 (G), 832 (C), 835 (G), 865 (C), 868 (T), 895 (C), 898 (A), 916 (C), 922 (C).

Culture characteristics: Colonies on MEA are yellowish grey and flat with sparse aerial mycelium. Strains stain the agar dark brown. On PDA, colonies are dark grey and flat with a pale brown marginal zone, and they stain the agar light brown. Chlamydospores were formed.

Additional material examined : HUNGARY. KISKUNSÁG: semiarid sandy open grassland near Fülöpháza, N46° 52′ E19° 25′, on the roots of Festuca vaginata, 22 Apr 2014, D.G. Knapp DSE881; ibid., DSE882; ibid., DSE884; ibid., DSE885.

Notes: Sterile, depressed, globose, sporocarp-like structures were formed on the surface of autoclaved stinging nettle and submerged in WA media supplemented with minced vegetables or pine needles kept at 20 °C 3 months after inoculation. The change in the color of the WA media with minced vegetables from orange to dark brown was observed.

Ecology and distribution: Sandy grasslands of the Kiskunság region of the Great Hungarian Plain, in the areas dominated by Festuca vaginata and Stipa borysthenica as dominant grasses. Isolates belonging to the genus Fuscosphaeria are root-colonizing fungi associated with F. vaginata in Fülöpháza, Hungary. There is neither an isolate/morph-based nor an uncultured sequence-based report of this species from any other geographical region.

Fig. 2 Fuscosphaeria hungarica (ex-holotype, CBS 147250). a Colony on MEA. b Colony on PDA. c, d Sporocarp-like structure produced on the surface of stinging nettle. e Developing sporocarp-like structure. F Cross section of a sporocarp-like structure formed submerged in WA media supplemented with pine needles. g Terminal chlamydospores produced on PDA. Scale bars: 50 μm.

Fig. 4 Phylogenetic tree of Fuscosphaeria hungarica isolates and representative species of families in the suborder Massarineae (Pleosporales). Strains presented in this study are shown in bold. The 50% majority rule consensus phylogram inferred from the Bayesian analysis of the combined dataset of four loci (ITS, LSU, SSU, TEF). Bayesian posterior probabilities (≥ 90) are shown before slashes, ML bootstrap support values (≥ 70) are shown after slashes. Leptosphaeria doliolum var. doliolum (CBS 505.75) served as outgroup. Highlighted sections indicate affiliations to families and asterisks indicate unknown clades sensu Tanaka et al. (2015). The scale bar indicates 0.5 expected changes per site per branch