Search for: All records

Summary Ascospores are the primary inoculum inFusarium graminearum. Interestingly, 70 of its genes have premature stop codons (PSC) and require A‐to‐I editing during sexual reproduction to encode full‐length proteins, including the ortholog of yeast Ama1, a meiosis‐specific activator of APC/C. In this study, we characterized the function ofFgAMA1and its PSC editing.FgAMA1was specifically expressed during sexual reproduction. TheFgama1mutant was normal in growth and perithecium formation but defective in ascospogenesis. Instead of forming four‐celled, uninucleate ascospores,Fgama1mutant produced oval, single‐celled, binucleated ascospores by selfing. Some mutant ascospores began to bud and underwent additional mitosis inside asci. Expression of the wild‐type or editedFgAMA1but not the uneditable allele complementedFgama1. In theFgama1xmat‐1‐1outcross, over 60% of the asci had eightFgama1or intermediate (elongated but single‐celled) ascospores, suggesting efficient meiotic silencing of unpairedFgAMA1. Deletion ofFgPAL1, one of the genes upregulated inFgama1also resulted in defects in ascospore morphology and budding. Overall, our results showed thatFgAMA1is dispensable for meiosis but important for ascospore formation and discharge. InF. graminearum, whereas some of its targets are functional during meiosis, FgAma1 may target other proteins that function after spore delimitation.