Investigating hybridisation between the forms of Pyrenophora teres based on Australian barley field experiments and cultural collections
Pyrenophora teres f. teres (Ptt) and P. teres f. maculata (Ptm) cause net and spot form of net blotch of barley (Hordeum vulgare L.), respectively. Both pathogens co-exist in barley fields and each can reproduce sexually, resulting in hybridisation and potential generation of novel virulences that could overcome barley host resistances. In this study, three field experiments were conducted during three successive years to investigate the occurrence of hybridisation. Susceptible barley was sown and inoculated with Ptt and Ptm. Form-specific PCR markers were used to analyse 822 conidia and 223 ascospores sampled from infected leaf tissue and 317 P. teres isolates collected across Australia during 1976–2015. None of the isolates were hybrids. Investigation of ascospores indicated that hybridisation had taken place within the forms, demonstrating preference for recombination within forms. Possible contributions of reproductive barriers have been appraised but further investigation is required to explore the rare hybridisation between the forms.
KeywordsSexual hybridisation Pyrenophora teres Reproductive isolation Pre- and post- mating barriers Form-specific markers Inter-form hybrids
The authors would like to thank Ryan Fowler (Department of Agriculture and Fisheries, Queensland, Australia) and Dr. Sanjiv Gupta (Murdoch University, Western Australia) for the isolates provided by them. The authors would also like to thank Dr. Adam H. Sparks (Centre for Crop Health, University of Southern Queensland) for providing the script of Australian Map in R. This project (DAQ00187) was partly funded by the Grains Research and Development Corporation, Australia.
Compliance with ethical standards
This research does not contain any research involving humans or animals.
Conflict of interest
The authors declare no conflict of interest.
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