Biology and life cycle of the sex-altering fungus buffalograss bunt ( Salmacisia buchloëana )

The fungus Salmacisia buchloëana is able to parasitically castrate the dioecious species buffalograss (Bouteloua dactyloides) through induced hermaphroditism, which in turn increases the number of ovaries produced by infected plants. To gain a better understanding of the Salmacisia buchloëana–buffalograss pathosystem, this study attempts to provide information on the biology of the fungus itself. Analysis of the fungal host range has led to the determination that only buffalograss is a legitimate host, contrary to claims in the literature. Mating type loci were identified in the fungus, but due to the absence of a mating factor A (MFA) homolog, it is possible that the S. buchloëana a-locus no longer functions to regulate sexual compatibility. This work also is the first to describe the completion of the in vitro life cycle, progressing from the germination of teliospores to the production of a new generation of teliospores. To understand the factors regulating sporulation, several genes were identified in a transcriptomic analysis of S. buchloëana growing on different media that facilitated the occurrence of different developmental stages. This resulted in the identification of genes involved in carbohydrate and nitrogen utilization, suggesting that the ratio of sugars and nitrogen available in the medium may influence teliospore development.