| Authors | J.H. Ou, G.C. Lin & C.Y. Chen 2020 |
|---|---|
| Strain | 18075 |
| Classification | Hypocreales, Sarocladiaceae, Sarocladium |
| Culture collection | BCRC FU31126 |
| Detection frequency | Low |
| Accession number | LC461527 |
| Figure |  Fig. 1 Sarocladium sparsum. a–d. Colony on PDA (a), with reverse in b and MEA (c), with reverse in d. e–g, h. Conidiophores and phialides, with slimy conidial mass in h. i. Adelophialide and conidia. j. Sporodochium-like structure. k. Conidia. l. Transformed conidia. (All from strain BCRC FU31121, except f from strain SA 3-48) (Bars = 5 µm) |
| Colonies | Colonies on PDA attaining 12, 15, 16, 7 mm diam. after 7 days at 24°C, 28°C, 32°C, 37°C respectively, elevated, wooly, white, reverse salmon with pale yellow margin, producing diffuse pale brown pigment in some strains. Colonies on MEA attaining 20, 23, 24, 3 mm diam. after 7 days at 24°C, 28°C, 32°C, 37°C, respectively, flat, coarsely cottony, pale salmon, translucent, reverse salmon. |
| Sporodochia | Sporodochium-like structure occasionally present, as a single conidiophore bearing densely compact branches fasciculate terminal flask-shaped phialides, 5.5–12 × 1–1.5(2.0) µm. |
| Conidiophores | Conidiophores mononematous, macro- or micronematous, arising from submerged hyphae or aerial hyphae at nearly right angle. Conidiophores reduced and bearing single phialide, simple and 5–40 µm long, 1.5–2.0 µm wide at the base, terminating in 1–3 verticillately arranged phialides, or dichotomously branched, where the central primary axis indeterminate in growth with one or occasionally two lateral secondary axis arising along the primary axis, or where the central primary axis is determinate in growth and terminates in 2 branches, 1 of which being an independent secondary new axis appearing monochasial, and the other of which being a phialide; secondary axis developed in a similar manner as primary axis, tertiary axes hardly present. |
| Conidia | Conidia hyaline, 1-celled, ovoid to ellipsoidal with rounded ends, 2.5–3.5 × 1.0–1.5(2) µm (length/width ratio 2.15–2.8), guttulate, forming a slimy mass on top of phialides. Additional conidia, if present, granulate, cylindrical, up to 17 µm long, with rounded ends. |
| Note | Although Sarocladium sparsum, S. attenuatum and S. oryzae are closely related, there are many characters distinct in S. sparsum. Conidiophores in S. sparsum are only sparsely branched and branches and phialides are typically at least slightly diverging and rarely adpressed. Length/width ratio of conidia is significantly smaller. A brown pigment diffusing into the medium was observed in some S. sparsum strains (BCRC FU31125, BCRC FU31126, SA 3-49, BCRC FU31122). A similar pigment produced by an unidentified Sarocladium strain was observed by Bridge et al. (1989) and S. spinificis by Yeh and Kirschner (2014). In S. sparsum, an additional type of conidiophore, characterized by lying on medium surface and producing short and compact branches with clearly shorter phialides, was seen, and accordingly interpreted as a sporodochium-like structure. Strain CBS 414.81 was identified by Giraldo et al. (2015) as S. oryzae. All the nine strains of S. sparsum have identical ITS/LSU/ACT sequences, and did not produce a green pigment. ITS/LSU/ACT sequences of CBS 414.81 and strains of S. sparsum show 100% identity. Evidences provided clearly identify CBS 414.81 as a strain of S. sparsum, which also explains the lack of a green pigment.
Sarocladium sparsum strains and S. oryzae CBS 180.74 show 8/0/23 base differences in ITS/LSU/ACT sequences. Incidentally S. sparsum strains and S. attenuatum CBS 399.73 also show 8/0/23 base differences in ITS/LSU/ACT sequences. Pathogenicity was confirmed by artificial inoculation with 5 strains (SA 1-15, BCRC FU31121, BCRC FU31122, BCRC FU31126, BCRC FU31125). Grain discoloration, unfilled grains, and lesions on leaf sheaths were observed on inoculated rice plants. |
| Pathogenicity | This species causes rice sheath rot disease. |
| Specimens examined | Taiwan, Taichung City, rice grains, Jul 2018, Jie-Hao Ou, 18042 Taiwan, Miaoli County, rice grains, Sep 2018, Jie-Hao Ou, 18075 |
| ITS | GAGGGACATTACCAGAGTGCCATAGGCTCTCCAACCCATTGTGAACATACCTATCGTTCCCTCGGCGGGATCAGCGCGCGGCTGCCTCCGGGCTCCGGGCGTCCGCCGGGGACAACCAAACTCGAATTTTATAGTGATTCTCTGAGGGGCGAGAGCCCGAAAACAAAATAAATCAAAACTTTCAACAACGGATCTCTTGGCTCTGGCATCGATGAAGAACGCAGCGAAATGCGATAAGTAATGTGAATTGCAGAATTCAGTGAATCATCGAATCTTTGAACGCACATTGCGCCCGCCGGCACTCCGGCGGGCATGCCTGTCCGAGCGTCATTTCAACCCTCAGGAGCACCCTTCGGGGCGCACCTGGTGCTGGGGATCAGCGGCCCTCGCGGCCTCTGTCCCCCAAATTCAGTGGCGGTCGCGCCGCAGCCTCCCCTGCGTAGTAGCACAACCTCGCACCGGAGAGCGGAACGACCACGCCGTGAAACCCCCAACTTTTCAAGGTTGACCTCGGATCAGGTAGGAATACCCGCTGAACTTAA |
| LSU | ACCCGCTGAACTTAAGCATATCAATAAGCGGAGGAAAAGAAACCAACAGGGATTGCCTCAGTAACGGCGAGTGAAGCGGCAACAGCTCAAATTTGAAATCTGGCCGCAAGGTCCGAGTTGTAATTTGCAGAGGATGCTTTTGGCGAGGTGCCTTCCGAGTTCCCTGGAACGGGACGCCATAGAGGGTGAGAGCCCCGTACGGTTGGACCACCGAGCCTCTGTAAAGCTCCTTCGACGAGTCGAGTAGTTTGGGAATGCTGCTCTAAATGGGAGGTGTACGTCTTCTAAAGCTAAATACCGGCCAGAGACCGATAGCGCACAAGTAGAGTGATCGAAAGATGAAAAG |
| ACT | GTCCTGCTCACCGAGGCGCCCATCAACCCCAAGTCCAACCGTGAGAAGATGACCCAGATCGTCTTCGAGACCTTCAACGCCCCCGCATTCTACGTCTCTATCCAGGCCGTTCTGTCCCTGTACGCCTCCGGTCGTACCACCGGTATCGTGCTGGACTCTGGTGATGGTGTCACTCACGTTGTCCCCATCTACGAGGGTTTCGCCCTCCCTCACGCCATTGCTCGTGTCGACATGGCTGGCCGTGATCTTACTGATTATCTCATGAAGATCCTTGCTGAGCGTGGTTACACCTTCTCCACCACCGCCGAGCGTGAAATCGTTCGTGACATCAAGGAGAAGCTTTGCTACGTCGCCCTCGACTTCGAGCAGGAGATCCAGACCGCCGCCCAGTCCTCTAGCCTCGAGAAGTCTTACGAGCTTCCTGATGGCCAGGTCATTACCATCGGCAACGAGCGATTCCGCGCCCCTGAGGCTCTCTTCCAGCCCTCTGTCCTCGGTCTCGAGAGCGGTGGTATCCACGTCACCACTTTCAACTCCATCATGAAGTGCGATGTCGACGTCCGAAAGGATCTCTACGGCAACATCGTCATGGTATGTTTTAGGGTCAACCCAGAGATATGATGATTGAAAACTAATCATGACTTAGTCTGGTGGTACCACCATGTACCCTGGTCTCTCCGACCGTATGCAGAAGGAGATCACTGCTCTTGCTCCTTCTTCCATGAAGGTCAAGATCATTGCTCCTCCGGAGCGCAAGTACTCTGTC |
| TUB | AGGACGTTGTCAACAAGCTCAGCACCCTCAGTGTAGTGACCCTTGGCCCAGTTGTTGCCAGCACCGGACTGGCCGAAAACGAAGTTGTCGGGGCGGAAAAGCTGACCGAAGGGACCGGCACGGACGGCGTCCATGGTACCGGGCTCAAGATCGACGAGGACAGCGCGAGGAACATACTTGTTGCCGGAGGCCTGAAGAGGCGGTCAGTGGGTCCACAGCAAGCAAGAGACGCGTTGCTGGCATCTCTCGGTCAAATCCAACCACGAACCTCGTTGAAGTAGACGCTCATGCGCTCGAGCTGGAGCTCAGAGGTGCCGTTGTAGATACCATTGCTGTCGAGACCGTGCTCGCCGGAGATGGTCTGCCAGAAAGCAGCACCAACTTGGTTGCCCTAGATCGAAAACATGGTGAGCCCCGCACATGAAAGTCGAGATGGGAGCTGTTGCAGCTACTTACGCACTGGCCGGTCTGGAGGTGAATCTATTTGCAAAAGAAAAAAGATATGGTCAGCAAGCTGTTTCTCTCTCAAAGCTTCATCGTATGTGTTGACACGCCGCATGGTGACATCCCAAGGCCTTGGTGGTACCCCGCCACGAGTTTAGGGGTAACAACGGTTTTGCTGGCAACAAAGGAACGCGTCGCGGGGGGGGGTTCGAGGCTCGTGGCGCATGGGCGGGAGAAGGAATGGAACTCACAATC |