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Fusarium and Sarocladium Species Associated with Rice Sheath Rot Disease in Sub-Saharan Africa

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Relation http://oar.icrisat.org/12493/
https://www.mdpi.com/1424-2818/15/10/1090
https://doi.org/10.3390/d15101090
 
Title Fusarium and Sarocladium Species Associated with Rice Sheath
Rot Disease in Sub-Saharan Africa
 
Creator Afolabi, O O
Bigirimana, V de P
Hua, G K H
Oni, F E
Bertier, L
Onwughalu, J
Oyetunji, O E
Ogunbayo, A
Velde, M V D
Nyamangyoku, O I
Saeger, S D
Höfte, M
 
Subject Rice
Plant Pathology
 
Description Sarocladium and Fusarium species are commonly identified as causal agents of rice sheath rot disease worldwide. However, limited knowledge exists about their genetic, pathogenic, and toxigenic diversity in sub-Saharan African (SSA) countries, where an increasing incidence of this disease has been observed. In this study, seventy fungal isolates were obtained from rice plants displaying disease symptoms in rice research programs and farmer fields in Mali, Nigeria, and Rwanda. Thus, an extensive comparative analysis was conducted to assess their genetic, pathogenic, and toxigenic diversity. The Fusarium spp. were characterized using the translation elongation factor (EF-1a) region, while a concatenation of Internal Transcribed Spacer (ITS) and Actin-encoding regions were used to resolve Sarocladium species. Phylogenetic analysis revealed four Fusarium
species complexes. The dominant complex in Nigeria was the Fusarium incarnatum-equiseti species complex (FIESC), comprising F. hainanense, F. sulawesiense, F. pernambucatum, and F. tanahbumbuense, while F. incarnatum was found in Rwanda. The Fusarium fujikuroi species complex (FFSC) was
predominant in Rwanda and Mali, with species such as F. andiyazi, F. madaense, and F. casha in Rwanda and F. annulatum and F. nygamai in Mali. F. marum was found in Nigeria. Furthermore, Fusarium oxysporum species complex (FOSC) members, F. callistephi and F. triseptatum, were found in Rwanda and Mali, respectively. Two isolates of F. acasiae-mearnsii, belonging to the Fusarium sambucinum
species complex (FSAMSC), were obtained in Rwanda. Isolates of Sarocladium, which were previously classified into three phylogenetic groups, were resolved into three species, which are attenuatum, oryzae, and sparsum. S. attenuatum was dominant in Rwanda, while S. oryzae and S. sparsum were
found in Nigeria. Also, the susceptibility of FARO44, a rice cultivar released by Africa Rice Centre (AfricaRice), was tested against isolates from the four Fusarium species complexes and the three Sarocladium species. All isolates evaluated could induce typical sheath rot symptoms, albeit with varying disease development levels. In addition, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to determine variation in the in vitro mycotoxins of the Fusarium species. Regional differences were observed in the in vitro mycotoxins profiling. Out of the forty-six isolates
tested, nineteen were able to produce one to four mycotoxins. Notably, very high zearalenone (ZEN) production was specific to the two F. hainanense isolates from Ibadan, Nigeria, while Fusarium nygamai isolates from Mali produced high amounts of fumonisins. To the best of our knowledge, it seems that this study is the first to elucidate the genetic, pathogenic, and toxigenic diversity of Fusarium species
associated with the rice sheath rot disease complex in selected countries in SSA.
 
Publisher MDPI
 
Date 2023-10-17
 
Type Article
PeerReviewed
 
Format application/pdf
 
Language en
 
Rights cc_attribution
 
Identifier http://oar.icrisat.org/12493/1/Diversity_15_10_1-22_2023.pdf
Afolabi, O O and Bigirimana, V de P and Hua, G K H and Oni, F E and Bertier, L and Onwughalu, J and Oyetunji, O E and Ogunbayo, A and Velde, M V D and Nyamangyoku, O I and Saeger, S D and Höfte, M (2023) Fusarium and Sarocladium Species Associated with Rice Sheath Rot Disease in Sub-Saharan Africa. Diversity (TSI), 15 (10). pp. 1-22. ISSN 1424-2818