Genetic fingerprinting and aflatoxin production of Aspergillus section Flavi associated with groundnut in eastern Ethiopia

BMC Microbiology

Jaime Martínez-Castillo¹  David A. Hoisington²  Alemayehu Chala³  Chris O. Ojiewo⁴  Amare Ayalew⁵  Chemeda Fininsa⁶  Mashilla Dejene⁶  Abdi Mohammed⁶  Victor S. Sobolev⁷  Renee S. Arias⁷  Paola C. Faustinelli⁷ 

[1] Centro de Investigación Científica de Yucatán A.C., Unidad de Recursos Naturales, Calle 43 No. 130, Colonia Chuburná de Hidalgo CP 97200, Mérida, Mexico;College of Agriculture and Environmental Sciences, Peanut and Mycotoxin Innovation Lab, University of Georgia, 30602-4356, Athens, GA, USA;College of Agriculture, Hawassa University, P.O. Box 5, Hawassa, Ethiopia;ICRISAT – Nairobi, Box 39063-00623, UN-Avenue, Nairobi, Kenya;Partnership for Aflatoxin Control in Africa (PACA), African Union Commission, Addis Ababa, Ethiopia;School of Plant Science, College of Agriculture and Environmental Sciences, Haramaya University, P.O. Box 138, Dire Dawa, Ethiopia;United States Department of Agriculture-Agricultural Research Service-National Peanut Research Laboratory, 39842-0509, Dawson, GA, USA;

关键词: Aflatoxin;    Aspergillus;    Genetic diversity;    Peanut;    Insertion/deletion markers;   

DOI  :  10.1186/s12866-021-02290-3

来源: Springer

【 摘 要 】

BackgroundAspergillus species cause aflatoxin contamination in groundnut kernels, being a health threat in agricultural products and leading to commodity rejection by domestic and international markets. Presence of Aspergillus flavus and A. parasiticus colonizing groundnut in eastern Ethiopia, as well as presence of aflatoxins have been reported, though in this region, no genetic studies have been done of these species in relation to their aflatoxin production.ResultsIn this study, 145 Aspergillus isolates obtained from groundnut kernels in eastern Ethiopia were genetically fingerprinted using 23 Insertion/Deletion (InDel) markers within the aflatoxin-biosynthesis gene cluster (ABC), identifying 133 ABC genotypes. Eighty-four isolates were analyzed by Ultra-Performance Liquid Chromatography (UPLC) for in vitro aflatoxin production. Analysis of genetic distances based on the approximately 85 kb-ABC by Neighbor Joining (NJ), 3D-Principal Coordinate Analysis (3D-PCoA), and Structure software, clustered the isolates into three main groups as a gradient in their aflatoxin production. Group I, contained 98% A. flavus, including L- and non-producers of sclerotia (NPS), producers of B1 and B2 aflatoxins, and most of them collected from the lowland-dry Babile area. Group II was a genetic admixture population of A. flavus (NPS) and A. flavus S morphotype, both low producers of aflatoxins. Group III was primarily represented by A. parasiticus and A. flavus S morphotype isolates both producers of B1, B2 and G1, G2 aflatoxins, and originated from the regions of Darolabu and Gursum. The highest in vitro producer of aflatoxin B1 was A. flavus NPS N1436 (77.98 μg/mL), and the highest producer of aflatoxin G1 was A. parasiticus N1348 (50.33 μg/mL), these isolates were from Gursum and Darolabu, respectively.ConclusionsTo the best of our knowledge, this is the first study that combined the use of InDel fingerprinting of the ABC and corresponding aflatoxin production capability to describe the genetic diversity of Aspergillus isolates from groundnut in eastern Ethiopia.Three InDel markers, AFLC04, AFLC08 and AFLC19, accounted for the main assignment of individuals to the three Groups; their loci corresponded to aflC (pksA), hypC, and aflW (moxY) genes, respectively. Despite InDels within the ABC being often associated to loss of aflatoxin production, the vast InDel polymorphism observed in the Aspergillus isolates did not completely impaired their aflatoxin production in vitro.

【 授权许可】

CC BY