Lee, Dong HyeonRoux, JolandaWingfield, Brenda D.Wingfield, Michael J.2016-03-042015-10Lee, DH, Roux, J, Wingfield, BD & Wingfield, MJ 2015, 'Variation in growth rates and aggressiveness of naturally occurring self-fertile and self-sterile isolates and the wilt pathogen Ceratocystis albifundus', Plant Pathology, vol. 64, no. 5, pp. 1103-1109.0032-0862 (print)1365-3059 (online)10.1111/ppa.12349http://hdl.handle.net/2263/51694Ceratocystis albifundus is the most important fungal pathogen of black wattle (Acacia mearnsii) grown in plantations in southern and eastern Africa. It is a homothallic fungus but also undergoes unidirectional mating type switching. As a result, the ascospore progeny can be either self-fertile or self-sterile. The only apparent difference between these mating types is the deletion of the MAT1-2-1 gene in self-sterile isolates. There is some evidence suggesting that self-sterile isolates grow more slowly than self-fertile isolates, but this has not been tested rigorously. The aim of this study was to determine whether self-sterile isolates are less fit by examining growth rate, relative germination rate and pathogenicity. Five self-sterile isolates were generated from each of five self-fertile isolates of C. albifundus and these 30 isolates were compared. The results showed that the self-sterile isolates grew consistently slower and were less pathogenic than the self-fertile isolates. The germination ratio of self-fertile to self-sterile isolates from single ascospores collected from the ascomata of five self-fertile isolates was on average 7:3. This could be a consequence of the self-sterile isolates having a lower germination rate. This observation, and the lower growth and pathogenicity levels, suggests that self-sterile isolates are not likely to compete effectively in nature, raising intriguing questions regarding their role and value to C. albifundus and other fungi having a similar mating system.en© 2015 British Society for Plant Pathology. This is the pre-peer reviewed version of the following article : Variation in growth rates and aggressiveness of naturally occurring self-fertile and self-sterile isolates of the wilt pathogen Ceratocystis albifundus,Plant Pathology, vol. 64, no. 5, pp. 1103-1109, 2015. 10.1111/ppa.12349. The definite version is available at : http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-3059.Ceratocystis albifundusFitnessSelf-fertile mating typeSelf-sterile mating typeBlack wattle (Acacia mearnsii)Postprint Article