Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Jul 31;10(8):535.
doi: 10.3390/jof10080535.

Molecular and Morphological Identification of Sarocladium Species Causing Sheath Rot of Rice in Thailand and Their Division into Physiological Races

Jintana Unartngam  1 , Noppol Kopmoo  2 , Umpawa Pinruan  2 , Chatchai Kosawang  3 , Hans Jørgen Lyngs Jørgensen  4
Affiliations

Molecular and Morphological Identification of Sarocladium Species Causing Sheath Rot of Rice in Thailand and Their Division into Physiological Races

Jintana Unartngam et al. J Fungi (Basel). .

Abstract

Sheath rot and dirty panicle are some of the major diseases of rice in Thailand. The diseases are traditionally considered to be caused by the pathogen Sarocladium oryzae and damage and lower both the quantity and quality of rice grain. In this study, 32 fungal isolates collected from the central and northeastern regions of Thailand were analysed phylogenetically using three molecular markers (ITS, D1/D2 of 28S rDNA and ACT) and physiological races were determined on 10 differential rice cultivars. We found that S. oryzae is not the only causal agent of sheath rot in Thailand, but S. attenuatum was also found. Despite having similar morphological features, the phylogenetic analysis recognised 11 of 32 isolates as S. attenuatum and the remaining isolates as S. oryzae. This is the first report of S. attenuatum causing sheath rot of rice in Thailand in addition to S. oryzae. Evaluation of physiological races revealed high pathogenic diversity of the two species. Thus, 16 and 11 physiological races were recorded from 21 isolates of S. oryzae and 11 isolates of S. attenuatum, respectively. These results indicate that both S. oryzae and S. attenuatum are the causal agents of rice sheath rot and dirty panicle in Thailand and that they are pathologically diverse.

Keywords: Sarocladium attenuatum; Sarocladium oryzae; dirty panicle; physiological races; sheath rot.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Morphological characteristics of S. oryzae (a–d) and S. attenuatum (e–h) isolated from sheath rot and dirty panicle diseases of rice. (a,b,e,f): colonies were grown on (a) PDA and (b) oatmeal agar (left seen from above and right from below); (c,d,g,h): simple and branched conidiophores, phialide producing conidia in chains, cylindrical conidia. Scale bars (a,b,e,f) = 1 cm; (c,d,g,h) = 10 μm.
Figure 2
Figure 2
Phylogenetic tree obtained from ITS rDNA, D1/D2 of 28S rDNA and ACT concatenated data of S. oryzae, S. attenuatum and other species from the GenBank database using maximum likelihood and Bayesian inference method. Bootstrap support values (1000 replications) above 50% are shown on the branches.
Figure 3
Figure 3
Dirty panicle and sheath rot on panicles and flag leaf sheaths at 21 days after inoculation with a spore suspension of (a) S. attenuatum isolate KKN0225 and (b) S. oryzae isolate KKN0122 on 10 differential rice cultivars.
See this image and copyright information in PMC

References

    1. Afolabi O.O., Bigirimana V.d.P., Hua G.K.H., Oni F.E., Bertier L., Onwughalu J., Oyetunji O.E., Ogunbayo A., Van De Velde M., Nyamangyoku O.I., et al. Fusarium and Sarocladium species associated with rice sheath rot disease in Sub-Saharan Africa. Diversity. 2023;15:1090. doi: 10.3390/d15101090. - DOI
    1. Unartngam J., Naunnet T., Sangsuk S., Chountragoon O., Kerdkhong C., Tantirungkij M. Effectiveness of bacteria isolated from peat swamp forests to control rice dirty panicle fungi in Thailand. AGRIVITA J. Agric. Sci. 2021;43:11. doi: 10.17503/agrivita.v43i2.2779. - DOI
    1. Riangwong K., Aesomnuk W., Sonsom Y., Siangliw M., Unartngam J., Toojinda T., Wanchana S., Arikit S. QTL-seq identifies genomic regions associated with resistance to dirty panicle disease in rice. Agronomy. 2023;13:1905. doi: 10.3390/agronomy13071905. - DOI
    1. CABI Sarocladium oryzae (rice sheath rot) CABI Compendium. 2022. [(accessed on 27 July 2024)]. Available online: https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.48393. - DOI
    1. Arunyanart P., Surin A., Sirisanta W., Napeerong N., Phutthasamai K. Studies on Rice Seed Discoloration Disease. Plant Pathology and Microbiology Division; Bangkok, Thailand: 1979.

LinkOut - more resources