In this work, Havenga et al characterized 41 isolates of T. destructans collected from a single eucalyptus plantation in Malaysia using MAT and SSR markers. The results obtained were compared with previously characterized T. destructans populations from other countries. The highest level of genetic and genotypic diversity was observed for the population from Malaysia with a signature of sexual recombination. An attempt to induce mating structures by crossing of isolates of opposite mating types were unsuccessful. Overall, the manuscript is clearly presented and provides a novel finding that is worthy of publication. I have some specific comments that are highlighted below.

1. It is unclear in the abstract that SSR markers were used to characterize the genetic diversity. I would suggest to change the sentence "The mating type and genotypes of 41 isolates from this Malaysian population were compared with those from other populations in South East Asia and South Africa" to "The mating type and SSR genotypes of 41 isolates from the Malaysian population were identified and compared with those from
   previously characterized populations in South East Asia and South Africa”

2. It would be useful to provide more information on the results of SSR genotyping obtained from this and the previous study (number of allele and allele sizes for each marker) (Havenga et al 2020 - Plant Pathology). This will help the readers to interpret and gain more insight into the work. This will enable future studies to make direct comparisons to the results obtained from this study. To achieve this, I would highly recommend the authors to provide the SSR genotyping data for all isolate analysed in this study in a form of a supplementary table. On this point, were the allele sizes determined using GeneScan confirmed with sequencing? It is considered best practice in SSR analysis to sequence and confirm the allele sizes obtained from GeneScan data. This would provide more confidence on the results, especially in the case if mono and di-repeat SSR markers were used. Confirming the allele size by sequencing also allow results from different studies to be compared with confidence. Was the GeneScan for this study done at the same time, condition and instrument to that of and Havenga et al 2020 - Plant Pathology? Making sure of all of these will omit the possibility that all new genotypes identified from Malaysian population is not a result of an artifact between runs.

3. No information on DAPC and STRUCTURE analyses were provided? How were the analyses conducted? How was the number of clusters identified in both of the analyses? Please provide BIC and DeltaK plots to support the number of clusters identified from DAPC and STRUCTURE.

4. In the discussion: change “… suggested the presence of an active sexual cycle” to “... suggested the presence of a cryptic sexual cycle”. This is because there is no evidence of “active” sexual reproduction in the populations.