Neopestalotiopsis sp. 3

Fallahi, Maryam, Armand, Alireza, Al-Otibi, Fatimah, Hyde, Kevin D. & Jayawardena, Ruvishika S., 2025, Pathogenic fungi (Sordariomycetes) associated with annual and perennial crops in Northern Thailand, MycoKeys 117, pp. 191-265 : 191-265

Neopestalotiopsis sp. 3

Fig. 34

Description.

Pathogenic to guava ( Psidium guajava ), and causes small brown leaf spots. Sexual morph not observed. Conidiomata acervular on PDA, solitary or aggregated, immersed or semi-immersed in agar medium containing the dark mass of conidia. Conidiophores reduced to conidiogenous cells. Conidiogenous cells ampulliform to lageniform, hyaline, 3–8 × 2–4 μm. Conidia, olivaceous to yellow-brown, fusiform, straight or slightly curved, 4 - septate, 21–29 × 4.5–6.5 μm (mean = 26 × 5.7 μm, n = 40); basal cell conic, hyaline, 4–7.3 μm long; three median cells 13–20.5 μm long, olivaceous to yellow-brown, septa darker than the rest of the cell; second cell from base yellow-brown, 4.5–9 μm long; third cell olivaceous, 4–7 μm long; fourth cell darker, 3–7 μm long; apical cell 4–5.5 μm long, conic, hyaline, smooth-walled, with 2–3 (mostly 2) tubular apical appendages, 3.5–18 μm long. Basal appendage single, unbranched, tubular, centric, 4–8 μm long.

Culture characteristics.

Colonies on PDA reach 60–70 mm in diameter after 7 days of growth at 25 ° C under 12 h daylight, white, edge undulate, with aerial mycelium on the surface, and black fruiting bodies. The reversing turn pale luteous with age.

Material examined.

Thailand • Chiang Rai Province, Phan District, Sai Khao , leaf spots on guava ( Psidium guajava ), February 2023, Maryam Fallahi, dried culture MF 107-1 ( MFLU 24-0255 ), living culture MFLUCC 24-0251 .

Notes.

Based on phylogenetic analysis of ITS, tub 2, and tef 1 sequence data, strain MFLUCC 24-0251 formed an independent subclade close to strains and type material of Neopestalotiopsis clavispora , N. cavernicola , and Neopestalotiopsis sp. 2 ( MFLUCC 24-0255 ) with no bootstrap support (Fig. 28 ), hence it was kept as an unidentified species, Neopestalotiopsis sp. 3 . The base pair differences between Neopestalotiopsis sp. 3 ( MFLUCC 24-0251 ) and N. clavispora ( MFUCC 12-0281 ), N. cavernicola ( KUMCC 20-0269 , ex-type strain), and Neopestalotiopsis sp. 2 are presented in Table 6 . Based on conidial morphology and colour, the length of conidia, and apical and basal appendage ( Maharachchikumbura et al. 2012; Liu et al. 2021), Neopestalotiopsis sp. 3 ( MFLUCC 24-0251 ) differs from the two above-mentioned species (Table 7 ).

Pathogenicity assay

Pathogenicity tests were conducted to verify the disease-causing capabilities of the strains of Colletotrichum (five strains), Diaporthe (six strains), Fusarium (five strains), and Neopestalotiopsis (five strains).

Pathogenicity tests were performed on five strains of Colletotrichum spp. , and all strains demonstrated pathogenicity towards their respective hosts, whereas the controls exhibited no symptoms (Fig. 35 ). Koch’s postulates were validated through the re-isolation of the same fungi and confirmation of their colony and morphological characteristics.

Pathogenicity tests were carried out on six strains of Diaporthe spp. , and all these strains demonstrated varying degrees of pathogenicity towards their host, while the controls remained symptom-free (Fig. 36 ). Koch’s postulates were validated through the re-isolation of the same fungi and confirmation of their colony and morphological characteristics.

Pathogenicity tests were carried out on five strains of Fusarium isolated from specific hosts, and all the strains were able to infect their hosts, while the controls displayed no symptoms (Fig. 37 ). Verification of Koch’s postulates was achieved by re-isolating the same fungi and confirming their colony and morphological characteristics.

Pathogenicity tests were conducted on five strains of Neopestalotiopsis spp. isolated from various host plants, and all the strains demonstrated pathogenic effects on their hosts, while the controls did not exhibit any symptoms (Fig. 38 ). Koch’s postulates were substantiated through the re-isolation of the same fungi and confirmation of their colony and morphological characteristics.

Figures

Figure 28. Phylogenetic tree of the Neopestalotiopsis ssp. generated by Bayes analysis of combined ITS, tef 1, and tub 2 sequence data. The ultrafast maximum likelihood (ML) bootstrap support values ≥ 50 % (BT) and Bayesian posterior probabilities ≥ 0.95 (BYPP) are shown, respectively, near the nodes. The ex-type strains are marked with an asterisk. The tree is rooted in Pestalotiopsis spathulate (CBS 356 86) and Pestalotiopsis diversiseta (MFLUCC 12 0287).

Figure 34. Neopestalotiopsis sp. 3 (MFLUCC 24-0251) a leaf spots in guava b front and c back views of the colony on PDA after 7 days d front and e back view of the colony on PDA after 60 days at 25 ° C f conidiomata g – i conidiophore and conidiogenous cells j – l conidia. Scale bars: 20 μm

Figure 35. Pathogenicity tests of five strains of Colletotrichum spp. on various hosts a – e pathogenicity tests of C. makassarense (MFLUCC 24-0237) on leaves and fruits of tamarind a controls (leaves) were assayed after three days b inoculated leaves after three days c controls (fruits) were assayed after two weeks d, e inoculated fruits after two weeks f – i pathogenicity tests of C. abelmoschi (MFLUCC 24-0239) on okra f, g controls were assayed after two weeks h, i inoculated fruits after two weeks j – o pathogenicity tests of C. fructicola (MFLUCC 24-0240) on leaves of jackfruit j – l controls were assayed after one week m – o inoculated leaves after one week p – u pathogenicity tests of C. siamense (MFLUCC 24-0235) on leaves of black pepper p – r controls were assayed after one week s – u inoculated leaves after one week v – y pathogenicity tests of C. plurivorum (MFLUCC 24-0238) on fruits of persimmon v, w controls were assayed after five days x, y inoculated fruits after five days.

Figure 36. Pathogenicity tests of six strains of Diaporthe spp. on various hosts a – d pathogenicity tests of D. sennicola (MFLUCC 24-0241) on okra a, b controls were assayed after two weeks c, d inoculated fruits after two weeks e – h pathogenicity tests of D. fistulosi (MFLUCC 24-0244) on spring onion e, f controls were assayed after one week g, h inoculated spring onions after one week i – o pathogenicity tests of D. hongkongensis (MFLUCC 24-0246) and D. siamensis (MFLUCC 24-0245) on rambutan i – k controls were assayed after one week l – o inoculated fruits by strain MFLUCC 24-0246 after one week. n, o inoculated fruits by strain MFLUCC 24-0245 after one week p – v pathogenicity tests of D. rosae (MFLUCC 24-0243) and D. melongenicola (MFLUCC 24-0242) on fruits of makhuea p – r controls were assayed after two weeks s, t inoculated fruits by strain MFLUCC 24-0243 after two weeks u, v inoculated fruits by strain MFLUCC 24-0242 after two weeks.

Figure 37. Pathogenicity tests of five strains of Fusarium spp. on various hosts. a – d Pathogenicity tests of F. sulawesiense (MFLUCC 24-0250) on mangosteen a, b controls were assayed after two weeks c, d inoculated fruits after two weeks e – h pathogenicity tests of F. tanahbumbuense (MFLUCC 24-0231) on leaves of durian e, f controls were assayed after five days g, h inoculated leaves after five days i, j pathogenicity tests of F. tanahbumbuense (MFLUCC 24-0231) on fruits of pepper i controls were assayed after one week j inoculated peppers after one week k – n pathogenicity tests of F. bubalinum (MFLUCC 24-0230) on the stem of dragon fruit k, l controls were assayed after two weeks m, n inoculated stems after two weeks o – r pathogenicity tests of F. nirenbergiae (MFLUCC 24-0248) on spring onion stem o, p controls were assayed after one week q, r inoculated spring onion after one week.

Figure 38. Pathogenicity tests of five strains of Neopestalotiopsis spp. on various hosts a – c pathogenicity tests of N. formicidarum (MFLUCC 24-0254) on rambutan a controls were assayed after one week b, c inoculated fruits after one week d – f pathogenicity tests of Neopestalotiopsis sp. 2 (MFLUCC 24-0255) on mangosteen d controls were assayed after two weeks e, f inoculated fruits after two weeks g – l pathogenicity tests of Neopestalotiopsis sp. 3 (MFLUCC 24-0251) on leaves of guava g – I controls were assayed after five days j – l inoculated leaves after five days m – p pathogenicity tests of N. zakeelii (MFLUCC 24-0252) on persimmon m, n controls were assayed after five days o, p inoculated fruits after five days q – v pathogenicity tests of Neopestalotiopsis sp. 1 (MFLUCC 24-0232) on leaves of sapodilla sapote q – s controls were assayed after five days t – v inoculated leaves after five days.