Biological Systems Engineering
Sixteen Draft Genome Sequences Representing the Genetic Diversity of Aspergillus flavus and Aspergillus parasiticus Colonizing Peanut Seeds in Ethiopia
Document Type Article
Abstract
Aspergillus flavus and Aspergillus parasiticus are commonly found in staple food grains such as maize, peanut, and many other crops (1). In seeds, these fungi can accumulate carcinogenic compounds called aflatoxins (2), as well as the neurotoxin cyclopiazonic acid (3). Aflatoxin accumulation in seeds can be controlled by plant host RNA interference-mediated silencing of fungal aflatoxin biosynthesis genes (4, 5); this requires knowing gene sequences of the invading fungus. A. flavus and A. parasiticus strains were collected from four peanut-growing districts in Ethiopia, namely, Fedis, Babile, Darolabu, and Gursum. The fungi were isolated on modified dichloran-rose bengal (MDRB) agar medium (6), restreaked onto MDRB agar, from which hyphal tips of single colonies were transferred to slants of Czapek’s medium (7), and identified following a previously described protocol (8). Cluster analysis of the genetic fingerprints of the isolates using the 25 insertion/deletion markers within the aflatoxin biosynthesis pathway and a protocol published by Faustinelli et al. (9) revealed several clades, from which 16 representative isolates (4 A. parasiticus strains, 5 A. flavus strains, 2 A. flavus L strains [10], and 5 A. flavus S strains [10]) were chosen for whole-genome sequencing, as reported in Table 1. DNA was extracted from spores and sclerotia using the DNeasy plant minikit (Qiagen, Valencia, CA) after growth of the isolates on MDRB agar for 3 days in the dark at 30°C.