Pseudophaeocytostroma bambusicola gen. et sp. nov. (Diaporthaceae) from bamboo in Yunnan, P. R. China Author Monkai, Jutamart 0000-0001-6043-0625 Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand & Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand & mjutamart @ gmail. com; https: // orcid. org / 0000 - 0001 - 6043 - 0625 mjutamart@gmail.com Author Phookamsak, Rungtiwa 0000-0002-6321-8416 Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand & Honghe Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Honghe 654400, P. R. China & jomjam. rp 2 @ gmail. com; https: // orcid. org / 0000 - 0002 - 6321 - 8416 jomjam.rp2@gmail.com Author Xu, Sheng 0000-0002-8911-3751 Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand & Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand & Honghe Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Honghe 654400, P. R. China & hambugerking 123 @ gmail. com; https: // orcid. org / 0000 - 0002 - 8911 - 3751 hambugerking123@gmail.com Author Xu, Jianchu 0000-0002-2485-2254 Honghe Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Honghe 654400, P. R. China & Centre for Mountain Futures (CMF), Kunming Institute of Botany, Kunming 650201, P. R. China & CIFOR-ICRAF China Program, World Agroforestry (ICRAF), Kunming 650201, P. R. China & jxu @ mail. kib. ac. cn; https: // orcid. org / 0000 - 0002 - 2485 - 2254 jxu@mail.kib.ac.cn Author Mortimer, Peter E. 0000-0002-8507-7407 Centre for Mountain Futures (CMF), Kunming Institute of Botany, Kunming 650201, P. R. China & peter @ mail. kib. ac. cn; https: // orcid. org / 0000 - 0002 - 8507 - 7407 peter@mail.kib.ac.cn Author Karunarathna, Samantha C. 0000-0001-7080-0781 Center for Yunnan Plateau Biological Resources Protection and Utilization, College of Biological Resource and Food Engineering, Qujing Normal University, Qujing 655011, P. R. China & samantha @ mail. kib. ac. cn; https: // orcid. org / 0000 - 0001 - 7080 - 0781 samantha@mail.kib.ac.cn Author Suwannarach, Nakarin 0000-0002-2653-1913 Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand & Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand & suwan _ 461 @ hotmail. com; https: // orcid. org / 0000 - 0002 - 2653 - 1913 suwan_461@hotmail.com Author Lumyong, Saisamorn 0000-0002-6485-414X Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand & Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand & Academy of Science, The Royal Society of Thailand, Bangkok 10300, Thailand & scboi 009 @ gmail. com; https: // orcid. org / 0000 - 0002 - 6485 - 414 X scboi009@gmail.com text Phytotaxa 2022 2022-11-01 571 1 39 51 journal article 177065 10.11646/phytotaxa.571.1.3 5b9115aa-3e83-4df8-a6fb-05970057f400 1179-3163 7270446 Pseudophaeocytostroma bambusicola Monkai & Phookamsak , sp. nov. FIGURE 3 Index Fungorum number : IF559821; Facesoffungi number : FoF 12717 Etymology : Refers to the host bamboo from which the holotype was collected. Holotype : KUN-HKAS 124569 ; living culture, KUMCC 22-12407 . Saprobic on dead bamboo culms. Sexual morph : Undetermined. Asexual morph : Coelomycetous. Conidiomata 89–420 high × 250–704 μm diam., pycnidial, immersed in the clypeus, becoming raised, erumpent, penetrating on host surface, with small black dots of conidial masses, hemispherical to subconical or lenticularis, uni- to bi-loculate, with an ostiole at the center, occasionally produced 2 ostioles in a locule, glabrous. Ostioles up to 80 μm wide, minutely papillate, immersed in host epidermis, circular. Conidiomatal wall up to 60 μm wide, consist of several layers of pseudoparenchymatous cells, arranged in a textura angularis , with dark brown outer layers and hyaline to pale brown towards the inner layers. Paraphyses 59–148 long × 2–3 μm wide ( x̅ = 99 × 2 μm, n = 20), intermingled between conidiophores, broadly filiform, septate, hyaline, unbranched, obtuse at the apex, with small granules. Conidiophores 4–10 × 2–5.5 μm ( x̅ = 6 × 3 μm, n = 20), tightly aggregated, subcylindrical to ampulliform, or irregular in shape, septate, hyaline to pale brown, branched only at the base. Conidiogenous cells 8–12.5 × 2–3 μm ( x̅ = 10 × 2.5 μm, n = 30), enteroblastic, phialidic, determinate, integrated, subcylindrical, tapering towards the apex, hyaline, smoothwalled. Conidia 9–13 × 3–4.5 μm ( x̅ = 11 × 4 μm, n = 30), oblong to ellipsoid, obtuse at both ends, aseptate, brown, thick and smooth-walled, guttules. Known distribution:— Yunnan , China Culture characteristics:— Conidium germinating on water agar within 24 h at 25 °C. Colonies on PDA reached 5 cm diam. after 7 days at 25 °C, effuse, sparse, entire edge, circular, white in surface, dark gray to black in reverse. Material examined:— China , Yunnan Province , Honghe Autonomous Prefecture , Honghe County , Honghe Hani Rice Terraces , on dead bamboo culms, 26 January 2021 , R . Phookamsak & S . C . Karunarathna , bn17 ( KUN-HKAS 124569 , holotype ), ex-type living culture = KUMCC 22-12407 ; ibid. , Honghe Autonomous Prefecture , Honghe County , Honghe Hani Rice Terraces , on dead bamboo culms, 26 January 2021 , R . Phookamsak & S . C . Karunarathna , bn14 ( KUN-HKAS 124568 ), living culture = KUMCC 22-12410 Notes:— The nucleotide BLAST search of ITS sequence indicated that Pseudophaeocytostroma bambusicola (KUMCC 22-12407) has the closest similarity with Phaeocytostroma sacchari strain CBS 275.34 with 96.26% similarity (Identities = 566/588, with 12 gaps), and is similar to Stenocarpella maydis strain Sm.A1-1, CBS 117558 (ex-epitype strain), CPC 16787, CPC 16786, CPC 16782, CPC 16781, CPC 16779, CPC 16778, CPC 16777 with 95.54% similarity (Identities = 552/579, with 5 gaps). The nucleotide BLAST search of LSU sequence indicated that Ps. bambusicola (KUMCC 22-12407) has the closest similarity with Massariothea thysanolaenae strain MFLUCC 15- 0452 (ex-type strain) with 99.64% similarity (Identities = 829/832, with no gap), and is similar to P. ambiguum strain CBS 128561, CPC 17077, CPC 17076, CPC 17074, CPC 16776 with 99.64% similarity (Identities = 829/832, with one gap). The nucleotide BLAST search of TEF1-α sequence indicated that Ps. bambusicola (KUMCC 22-12407) has the closest similarity with P. sacchari strain CBS 275.34 with 88.86% similarity (Identities = 303/341, with 11 gaps), and is similar to P. ambiguum strain CFMS_1294, CPC 17071 (ex-epitype strain), CPC 16776, CPC 17075 CPC 17074, CPC 17072, CPC 16775 with 84.83% similarity (Identities = 179/211, with 12 gaps). FIGURE 3. Pseudophaeocytostroma bambusicola (KUN-HKAS 124569, holotype ) a Conidiomata on host substrate b Section of a conidioma c Ostiole d Conidiomatal wall e Conidiophores f–h Conidiogenous cells and conidia i Paraphyses j–n Conidia o–p Colonies on PDA after 7 days (o from above, p from below). Scale bars: a = 500 μm, b = 200 μm, c = 100 μm, d = 20 μm, e – h = 10 μm, i = 20 μm, j – n = 10 μm. Pseudophaeocytostroma bambusicola is morphologically similar to Phaeocytostroma sacchari in having filiform paraphyses, aseptate, oblong to ellipsoid, brown, conidia with overlapping size (9–13 vs 9–14.5 μm) ( Sutton 1964 , 1980 , TABLE 2 ). However, our new species differs from P. sacchari in having uni- to bilocular conidiomata, minutely papillate ostiole with wider conidiomata (250–704 vs 350 μm) and not abundant, septate, longer paraphyses (59–148 vs 15–35 μm), while P. sacchari has abundant and aseptate paraphyses ( Sutton 1964 , 1980 , TABLE 2 ). The host preference of P. sacchari is Saccharum sp. , Sorghum sp. and Zea mays ( Sutton 1964 , Farr & Rossman 2022 , TABLE 2 ), whereas our new species was found on bamboo. In the phylogenetic analyses, Pseudophaeocytostroma bambusicola (KUMCC 22-12407, KUMCC 22-12410) formed a distinct subclade adjacent to Ps. “ sacchari ” strains CBS 275.34, UMICH-1, km-1 and 135 with high support (98% ML/95% MP/1.00 PP, FIGURE 1 ). The pairwise nucleotide comparison of ITS and TEF1-α sequence data revealed significant differences (more than 1.5%) between Ps. bambusicola (KUMCC 22-12407) and Ps. “ sacchari ” strains CBS 275.34, km-1, UMICH-1 and 135 for each gene region ( TABLE 3 ). The results of PHI test also supported the intraspecific variation among these strains and indicated the conspecific between strain UMICH-1 and km-1 ( FIGURE 2 ). Thus, Ps. bambusicola was proposed as a new species based on morphological and phylogenetic evidence. TABLE 2. Synopsis of Pseudophaeocytostroma and Phaeocytostroma species. The new species is indicated in black bold.

Species	Host*	Conidiomata	Paraphyses	Conidiophores	Conidia	References
Phaeocytostroma ambiguum	Sorghum bicolor , Zea mays and soil	Up to 550 long × 300 μm wide	40–65 × 2.5–3.5 μm	15–35 × 2–3.5 μm	Alpha conidia: 12–15 × 5.5–6.5 μm, ellipsoidal to pyriform, medium brown Beta conidia: 15–20 × 1.5–2 μm, subcylindrical, straight to slightly curved, hyaline	Petrak & Sydow (1927) , Lamprecht et al. (2011)
Phaeocytostroma calami	Calamus rotang	Up to 1000 μm diam.	40 × 2–2.5 μm	21 × 2–3 μm	8–9 × 2.5–3 μm, cylindrical, pale brown	Panwar & Bohra (1972) , Sutton (1980)
Phaeocytostroma istricum	Zea mays	Up to 1500 high × 350–1000 long × 500–2500 μm wide	Undetermined	40–60 × 1.5–2 μm	7.5–16 × 5–6 μm, ellipsoidal or elongate fusiform, olive-brown	Petrak (1921)
Phaeocytostroma megalosporum	Paddy field soil	Up to 2000 μm diam.	25–60 × 2.5–3.5 μm	15–35 × 2.5–3.5 μm	28–34.5 × 14–17 μm, fusiform to pyriform, dark brown	Sutton (1964)
Phaeocytostroma plurivorum	Helianthus annuus , Ipomoea batatas , Zea mays , sugarcane field soil and grassland soil	Up to 700 long × 300–400 μm wide	30–60 × 1.5–2 μm	13.5–20 × 3–4 μm	14–19 × 7–10.5 μm, pyriform to fusiform, brown	Sutton (1980)
Phaeocytostroma sacchari var. penniseti	Pennisetum purpureum	Up to 450 long × 300 μm wide	40–70 × 2 μm	10–25 × 2.5–4 μm	15.5–19 × 4–5 μm, ellipsoidal or ovate, pale brown	Sutton (1964)
Phaeocytostroma yomense	Decaying submerged wood	337–452 high × 246–393 μm diam.	Undetermined	Undetermined	14–23 × 3–6 μm, cylindrical- ellipsoidal, oblong allantoid, pale brown	Boonmee et al. (2021)
Pseudophaeocytostroma bambusicola	Bamboo	89–420 high × 250–704 μm diam.	59–148 × 2–3 μm	4–10 × 2–5.5 μm	9–13 × 3–4.5 μm, oblong to ellipsoidal, obtuse at both ends, pale brown	This study
Apluda mutica , Chasmopodium caudatum , Hyparrhenia hirta ,
Pseudophaeocytostroma “ sacchari ” (as Phaeocytostroma sacchari )	Pinus sp. , Saccharum officinarum , Saccharum munja , Saccharum sp. , Sorghum bicolor , Sorghum vulgare and Zea mays	Up to 650 long × 350 μm wide	15–35 × 2 μm	5–20 × 1.5–2 μm	9–14.5 × 3.5–5 μm, ellipsoidal or ovate, pale brown	Sutton (1964)

*The host data was also obtained from Farr & Rossman (2022) TABLE 3. The nucleotide differences between Pseudophaeocytostroma bambusicola and Ps. “ sacchari ” strains.

Pseudophaeocytostroma “ sacchari ” strains	Number of different nucleotides/number of all nucleotides (% base pairs difference)
ITS	TEF1-α
CBS 275.34	10/574 (1.74%)	30/331 (9.06%)
UMICH-1	9/518 (1.74%)	-
km-1	9/497 (1.81%)	-
135	17/444 (3.83%)	-

Phaeocytostroma sacchari was introduced and described by Sutton (1964) . Lamprecht et al. (2011) later provided the sequence data for P. sacchari , strain CBS 275.34 which was isolated from Japan without a mention of host substrates and no description provided. Carabez et al. (2014) isolated a fungus strain UMICH-1 from sugarcane displaying stalk rot symptoms in Mexico and identified it as P. sacchari based on morphology and the high similarity of the ITS blast search. Whereas, two strains of P. sacchari (km-1 and 135) were unpublished sequences from the GenBank. Thus, morphological descriptions are not available for these strains. Therefore, we treated these strains as Ps. “ sacchari ” until their correct identification could be confirmed. The examination of ex-type or epitype specimens, more fresh collections and additional sequences are needed for further studies on morphological and genetic variation in this group.