| Title: | Austropuccinia psidii uses tetrapolar mating and produces meiotic spores in older infections on Eucalyptus grandis |
| Author(s): | Ferrarezi JA; McTaggart AR; Tobias PA; Hayashibara CAA; Degnan RM; Shuey LS; Franceschini LM; Lopes MS; Quecine MC; |
| Address: | "Department of Genetics, College of Agriculture 'Luiz de Queiroz', University of Sao Paulo, Piracicaba-SP, 11 Padua Dias Avenue, 13418-900, Brazil. Electronic address: jessica.ferrarezi@usp.br. Centre for Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Ecosciences Precinct, Dutton Park 4102, QLD, Australia. Electronic address: a.mctaggart@uq.edu.au. School of Life and Environmental Sciences, University of Sydney, Camperdown, NSW 2006, Australia. Electronic address: peri.tobias@sydney.edu.au. Department of Genetics, College of Agriculture 'Luiz de Queiroz', University of Sao Paulo, Piracicaba-SP, 11 Padua Dias Avenue, 13418-900, Brazil. Electronic address: carolina.h@usp.br. Centre for Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Ecosciences Precinct, Dutton Park 4102, QLD, Australia. Electronic address: r.degnan@uq.net.au. Queensland Department of Agriculture and Fisheries, Ecosciences Precinct, 41 Boggo Rd, Dutton Park QLD 4102, Australia. Electronic address: louise.shuey@daf.qld.gov.au. Department of Genetics, College of Agriculture 'Luiz de Queiroz', University of Sao Paulo, Piracicaba-SP, 11 Padua Dias Avenue, 13418-900, Brazil. Electronic address: livia_mf@yahoo.com.br. Department of Genetics, College of Agriculture 'Luiz de Queiroz', University of Sao Paulo, Piracicaba-SP, 11 Padua Dias Avenue, 13418-900, Brazil. Electronic address: marianasilva_lopes@hotmail.com. Department of Genetics, College of Agriculture 'Luiz de Queiroz', University of Sao Paulo, Piracicaba-SP, 11 Padua Dias Avenue, 13418-900, Brazil. Electronic address: mquecine@usp.br" |
| DOI: | 10.1016/j.fgb.2022.103692 |
| ISSN/ISBN: | 1096-0937 (Electronic) 1087-1845 (Linking) |
| Abstract: | "Austropuccinia psidii is the causal agent of myrtle rust, a fungal disease that infects over 480 species in the Myrtaceae. A. psidii is a biotrophic pathogen that reproduces sexually and asexually. Sexual reproduction has been previously shown on Syzygium jambos and little is known about its reproductive biology on other hosts or whether populations that were formerly structured by host range can outcross on universally susceptible hosts. We investigated if mating genes in three genomes of A. psidii were under selection as a proxy for whether different strains can reproduce sexually on a shared host. We examined three homologs of the STE3.2 gene, sequences of which were near-identical in the three genomes, and the homeodomain locus, which contained two alleles of two homeodomain genes in each genome. A. psidii likely uses tetrapolar mating. Pheromone/receptor loci were distal to homeodomain loci, and based on haplotypes of a phased assembly, mate compatibility is regulated by multiallelic HD genes and biallelic STE3.2 genes; the third homolog of STE3.2 (STE3.2-1) was present in both haplotypes, and our study supports hypotheses this gene does not regulate mate recognition. Populations of A. psidii formerly structured by host range could potentially outcross on universal hosts based on their related mating genes, however this hypothesis should remain theoretical given the implications for biosecurity. Additionally, we searched for core meiotic genes in genomes of A. psidii, four species of Puccinia, and Sphaerophragmium acaciae through comparative genomics based on 136 meiosis-related orthologous genes modeled from Mycosarcoma maydis. Meiotic genes are conserved in rust fungi at family rank. We analyzed the expression of two meiotic and four mitotic genes of A. psidii on E. grandis over a 28-day time course to validate that identified meiotic genes were upregulated in teliospores. Three mitotic genes were significantly downregulated in samples collected 28 days after inoculation (DAI) compared to 14 DAI. Expression of meiotic genes was significantly up-regulated in samples collected 28 DAI compared to 14 DAI, indicating a temporal switch from production of uredinia (mitotic stage) to telia in the life cycle, which we hypothesize may be in response to leaf ageing" |
| Keywords: | *Basidiomycota/genetics *Eucalyptus/genetics/microbiology Plant Diseases/microbiology Reproduction Spores Meiosis Mitosis Myrtle rust Sexual reproduction Teliospore Time course; |
| Notes: | "MedlineFerrarezi, Jessica A McTaggart, Alistair R Tobias, Peri A Hayashibara, Carolina A A Degnan, Rebecca M Shuey, Louise S Franceschini, Livia M Lopes, Mariana S Quecine, Maria C eng Research Support, Non-U.S. Gov't 2022/04/19 Fungal Genet Biol. 2022 May; 160:103692. doi: 10.1016/j.fgb.2022.103692. Epub 2022 Apr 15" |
