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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Mycotoxin Prevention and Applied Microbiology Research » Research » Publications at this Location » Publication #356841
Research Project: Genomic and Metabolomic Approaches for Detection and Control of Fusarium, Fumonisins and Other Mycotoxins on Corn

Location: Mycotoxin Prevention and Applied Microbiology Research

Title: Identification of a genetic element required for spore killing in Neurospora

Author
item RHODES, NICHOLAS - Illinois State University
item HARVEY, AUSTIN - Illinois State University
item SAMARAJEEWA, DILINI - Illinois State University
item SVEDBERG, JESPER - Uppsala University
item YUSIFOV, AYKHAN - Illinois State University
item ABUSHAREKH, A - Illinois State University
item MANITCHOTPISIT, P - Illinois State University
item Brown, Daren
item SHARP, KEVIN - Illinois State Museum
item REHARD, DAVID - University Of Missouri

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/21/2018
Publication Date: 10/21/2018
Citation: Rhodes, N.A., Harvey, A.M., Samarajeewa, D.A., Svedberg, J., Yusifov, A., Abusharekh, A., Manitchotpisit, P., Brown, D.W., Sharp, K.J., Rehard, D.G. 2018. Identification of a genetic element required for spore killing in Neurospora [abstract].

Interpretive Summary:

Technical Abstract: Standard Mendelian genetics dictates that each allele in a sexual cross has an equal probability of being inherited by the proceeding generation. Meiotic drive elements are “selfish” genetic elements that actively bias inheritance frequency in their favor. Although multiple meiotic drive elements have been identified in fungi, including the Neurospora Spore killer-2 element (Sk-2), their mechanism of action is poorly understood. Crosses of Sk-2 ' SkS (Spore killer-sensitive) produce asci with four black, viable ascospores and four white, inviable, “killed” ascospores. The four surviving ascospores almost always inherit the Sk-2 element, resulting in a nearly 100% biased transmission of Sk-2 to the surviving population. Previous work has identified one gene, rsk (resistance to Spore killer), and one locus, rfk-1 (required for killing) that are involved in the spore killing mechanism. Here we identify a 1481 bp region within the previously identified 45kb rfk-1 locus that is associated with spore killing. Deletion of this 1481 bp region from Sk-2 results in the loss of spore killing. In a Sk-2 strain that has lost the ability to kill (ISU-3211), the 1481 bp region contains seven point mutations, one of which (G28326A) we found is sufficient for the loss of spore killing. A potential start codon for an RFK-1 protein was identified 62 bp upstream of the G28326A mutation. Spore killing occurs normally when a non-native promoter is fused to this start codon, suggesting that rfk-1 encodes a protein of at least 39 amino acids. We also show that the rfk-1 gene has evolved from a predicted Neurospora gene ncu07086. The significance of this finding with respect to the killing mechanism will be discussed.