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Luo Z, McTaggart A, Schwessinger B. Genome biology and evolution of mating-type loci in four cereal rust fungi. PLoS Genet 2024; 20:e1011207. [PMID: 38498573 PMCID: PMC10977897 DOI: 10.1371/journal.pgen.1011207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 03/28/2024] [Accepted: 03/04/2024] [Indexed: 03/20/2024] Open
Abstract
Permanent heterozygous loci, such as sex- or mating-compatibility regions, often display suppression of recombination and signals of genomic degeneration. In Basidiomycota, two distinct loci confer mating compatibility. These loci encode homeodomain (HD) transcription factors and pheromone receptor (Pra)-ligand allele pairs. To date, an analysis of genome level mating-type (MAT) loci is lacking for obligate biotrophic basidiomycetes in the Pucciniales, an order containing serious agricultural plant pathogens. Here, we focus on four species of Puccinia that infect oat and wheat, including P. coronata f. sp. avenae, P. graminis f. sp. tritici, P. triticina and P. striiformis f. sp. tritici. MAT loci are located on two separate chromosomes supporting previous hypotheses of a tetrapolar mating compatibility system in the Pucciniales. The HD genes are multiallelic in all four species while the PR locus appears biallelic, except for P. graminis f. sp. tritici, which potentially has multiple alleles. HD loci are largely conserved in their macrosynteny, both within and between species, without strong signals of recombination suppression. Regions proximal to the PR locus, however, displayed signs of recombination suppression and genomic degeneration in the three species with a biallelic PR locus. Our observations support a link between recombination suppression, genomic degeneration, and allele diversity of MAT loci that is consistent with recent mathematical modelling and simulations. Finally, we confirm that MAT genes are expressed during the asexual infection cycle, and we propose that this may support regulating nuclear maintenance and pairing during infection and spore formation. Our study provides insights into the evolution of MAT loci of key pathogenic Puccinia species. Understanding mating compatibility can help predict possible combinations of nuclear pairs, generated by sexual reproduction or somatic recombination, and the potential evolution of new virulent isolates of these important plant pathogens.
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Affiliation(s)
- Zhenyan Luo
- Research Biology School, Australian National University, Canberra, ACT, Australia
| | - Alistair McTaggart
- Centre for Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Ecosciences Precinct, Dutton Park, Queensland, Australia
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Hayashibara CADA, Lopes MDS, Tobias PA, dos Santos IB, Figueredo EF, Ferrarezi JA, Marques JPR, Marcon J, Park RF, Teixeira PJPL, Quecine MC. In Planta Study Localizes an Effector Candidate from Austropuccinia psidii Strain MF-1 to the Nucleus and Demonstrates In Vitro Cuticular Wax-Dependent Differential Expression. J Fungi (Basel) 2023; 9:848. [PMID: 37623619 PMCID: PMC10455828 DOI: 10.3390/jof9080848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/26/2023] Open
Abstract
Austropuccinia psidii is a biotrophic fungus that causes myrtle rust. First described in Brazil, it has since spread to become a globally important pathogen that infects more than 480 myrtaceous species. One of the most important commercial crops affected by A. psidii is eucalypt, a widely grown forestry tree. The A. psidii-Eucalyptus spp. interaction is poorly understood, but pathogenesis is likely driven by pathogen-secreted effector molecules. Here, we identified and characterized a total of 255 virulence effector candidates using a genome assembly of A. psidii strain MF-1, which was recovered from Eucalyptus grandis in Brazil. We show that the expression of seven effector candidate genes is modulated by cell wax from leaves sourced from resistant and susceptible hosts. Two effector candidates with different subcellular localization predictions, and with specific gene expression profiles, were transiently expressed with GFP-fusions in Nicotiana benthamiana leaves. Interestingly, we observed the accumulation of an effector candidate, Ap28303, which was upregulated under cell wax from rust susceptible E. grandis and described as a peptidase inhibitor I9 domain-containing protein in the nucleus. This was in accordance with in silico analyses. Few studies have characterized nuclear effectors. Our findings open new perspectives on the study of A. psidii-Eucalyptus interactions by providing a potential entry point to understand how the pathogen manipulates its hosts in modulating physiology, structure, or function with effector proteins.
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Affiliation(s)
- Carolina Alessandra de Almeida Hayashibara
- Department of Genetics, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba 13418-900, SP, Brazil; (C.A.d.A.H.); (M.d.S.L.); (I.B.d.S.); (J.A.F.); (J.M.)
| | - Mariana da Silva Lopes
- Department of Genetics, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba 13418-900, SP, Brazil; (C.A.d.A.H.); (M.d.S.L.); (I.B.d.S.); (J.A.F.); (J.M.)
| | - Peri A. Tobias
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW 2006, Australia;
| | - Isaneli Batista dos Santos
- Department of Genetics, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba 13418-900, SP, Brazil; (C.A.d.A.H.); (M.d.S.L.); (I.B.d.S.); (J.A.F.); (J.M.)
| | | | - Jessica Aparecida Ferrarezi
- Department of Genetics, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba 13418-900, SP, Brazil; (C.A.d.A.H.); (M.d.S.L.); (I.B.d.S.); (J.A.F.); (J.M.)
| | - João Paulo Rodrigues Marques
- Department of Basic Sciences, Faculty of Animal Science and Food Engineering, University of São Paulo, Pirassununga 13635-900, SP, Brazil;
| | - Joelma Marcon
- Department of Genetics, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba 13418-900, SP, Brazil; (C.A.d.A.H.); (M.d.S.L.); (I.B.d.S.); (J.A.F.); (J.M.)
| | - Robert F. Park
- School of Life and Environmental Sciences, Plant Breeding Institute, The University of Sydney, Cobbitty, NSW 2570, Australia;
| | - Paulo José Pereira Lima Teixeira
- Department of Biological Sciences, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba 13418-900, SP, Brazil;
| | - Maria Carolina Quecine
- Department of Genetics, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba 13418-900, SP, Brazil; (C.A.d.A.H.); (M.d.S.L.); (I.B.d.S.); (J.A.F.); (J.M.)
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