Pseudopestalotiopsis chinensis F. Liu & L. Cai

Koodalugodaarachchi, Vidyamali, Thilini Chethana, K. W., Jayawardena, Ruvishika S., Bundhun, Digvijayini, Aluthmuhandiram, Janith V. S., Suwannarach, Nakarin, Manawasinghe, Ishara S. & Lumyong, Saisamorn, 2024, New records of Pestalotioid species associated with leaf spot disease on Camellia sinensis from northern Thailand, Phytotaxa 647 (1), pp. 91-114 : 103-105

Pseudopestalotiopsis chinensis F. Liu & L. Cai , Scientific Reports 7:866 (2017)

MycoBank: MB 818923, Faces of fungi number: FoF 09399, Figure 4

Description:—Associated with the leaf lesions of diseased leaves of Camellia sinensis var. assamica . Appearing as black spots on dead leaf epidermis. Asexual morph: On PDA, Conidiomata pycnidial, 114–278 μm diam. (x̅ = 196 μm), semi-immersed to partially erumpent from the substrate, aggregated or scattered, globose, reniform or oblong, exude black, slimy, glistening conidial masses. Conidiophores indistinct and reduced to conidiogenous cells. Conidiogenous cells 7–29 × 2–6 μm (x̅ = 14.6 × 3.3 μm, n = 20), distinct or integrated, annellidic, obovoid, pyriform, clavate or spathulate, hyaline, smooth, thin-walled. Conidia 9.3–32.0 × 4.2–7.2 μm (x̅ = 21.8 × 5.8 μm, n = 20), fusoid, ellipsoid, straight to slightly curved, 4-septate, slightly constricted at the septum, hyaline or pale brown initially, turning to dark brown, smooth, thin-walled at maturity; basal cell conic to acute or obconic, 1–6 μm long (x̅ = 3.3 μm, n = 20); three median cells equal, each 1.2–7.4 μm long (x̅ = 4.7 μm, n = 20), doliiform, concolorous, pale brown to dark brown or olivaceous, septa darker than rest of the cell, wall slightly rugose; second cell from the base 1.2–7.4 μm long; third cell 2.7–6.8 μm long; fourth cell 2.5–7.1 μm long; apical cell 1.1–5.0 μm long (x̅ = 3.1 μm, n = 20), hyaline, subcylindrical to obconic, with 2–3 tubular appendages arising from the crest of the apical cell at different loci, unbranched, flexuous, filiform 4.7–33.5 μm long (x̅ = 20.6 μm, n = 20); basal appendage single, tubular, unbranched, centric, 3.1–11.1 μm long, (x̅ = 5.6 μm, n = 20). Sexual morph: Not observed.

Culture characteristics:—Colonies on the PDA irregular-shaped, attaining 30–40 mm diam. after seven days at 25 °C, with smooth, undulated margin, surface white, cottony, moderate aerial mycelium clots concentrated along the colony margin, flat elevation, reverse yellowish. Sporulates after 15 days; conidiomata black, gregarious.

Known hosts:—Pathogenic, causing grey blight disease on leaves of Camellia sinensis ( Theaceae ) ( Liu et al. 2017, Wang et al. 2019 a, b, Tsai et al. 2021) and associated with leaf spots of Camellia sinensis var. assamica (this study).

Known distribution:— China ( Liu et al. 2017, Wang et al. 2019 a, b, Tsai et al. 2021), Thailand (this study).

Material examined:— Thailand, Chiang Mai Province, Mae Taeng District, Ban Pang Makluay Community Forest, alt. 530 m, on symptomatic leaf of Camellia sinensis var. assamica ( Theaceae ), 28 September 2022, V. Koodalugodaarachchi (MFLU 23-0398), living culture MFLUCC 23-0261.

Notes:— Pseudopestalotiopsis chinensis was introduced by Liu et al. (2017) as the causal agent of the grey blight disease of Camellia sinensis from China. Our isolate (MFLUCC 23-0261) shares similar morphological characteristics with the type of Ps. chinensis (LC3011), in having conidia with 2–3 tubular, apical appendages. The two strains slightly differ from each other only in the conidial sizes (9.3–32.0 × 4.2–7.2 μm vs 25.5–35.5 × 6–9 μm) and median cell lengths (1.2–7.4 vs 4.5–8.5 μm). According to the multi-locus phylogeny, our isolate (MFLUCC 23-0261) clustered with Ps. chinensis (LC6629) with 99% MLBS, 82% MPBS, and 1.00 BYPP. Base pair comparison between Ps. chinensis (LC6629) and our isolate (MFLUCC 23-0261) demonstrated slight nucleotide differences only in the tub2 (0.48%) and tef1-α (0.44%) regions. Thus, based on morphological and phylogenetic evidences, we identify our isolate as a new geographical record of Ps. chinensis in Thailand.

Figures

FIGURE 4. Pseudopestalotiopsis chinensis (MFLU23-0398 (a–e), MFLUCC 23-0261 (f–r), new geographical record). a Diseased leaf of Camellia sinensis var. assamica. b Close-up of the lesion. c Acervular fruiting bodies on the lesion. d Section of a fruiting body on specimen. e Conidiogenous cells of a fruiting body on the specimen. f Upper view of culture on the PDA (at 25 °C). g Reverse view of culture on the PDA (at 25 °C). h–i Pycnidia on the PDA. j Mycelium on the PDA. k–l Conidiogenous cells in culture. m–r Conidia. Scale bars: d, k–r = 20 μm, e = 5 μm, i =100 μm, j = 200 μm.