Efflux Pumps and Multidrug-Resistance in <i>Pyricularia oryzae</i> <i>Triticum</i> Lineage
Samara Nunes Campos Vicentini,
Silvino Intra Moreira,
Abimael Gomes da Silva,
Tamiris Yoshie Kiyama de Oliveira,
Tatiane Carla Silva,
Fabio Gomes Assis Junior,
Loane Dantas Krug,
Adriano Augusto de Paiva Custódio,
Rui Pereira Leite Júnior,
Paulo Eduardo Teodoro,
Bart Fraaije,
Paulo Cezar Ceresini
Affiliations
Samara Nunes Campos Vicentini
Department of Crop Protection, Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos), Sao Paulo State University, UNESP, Ilha Solteira 15385-000, SP, Brazil
Silvino Intra Moreira
Department of Crop Protection, Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos), Sao Paulo State University, UNESP, Ilha Solteira 15385-000, SP, Brazil
Abimael Gomes da Silva
Department of Crop Protection, Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos), Sao Paulo State University, UNESP, Ilha Solteira 15385-000, SP, Brazil
Tamiris Yoshie Kiyama de Oliveira
Department of Crop Protection, Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos), Sao Paulo State University, UNESP, Ilha Solteira 15385-000, SP, Brazil
Tatiane Carla Silva
Department of Crop Protection, Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos), Sao Paulo State University, UNESP, Ilha Solteira 15385-000, SP, Brazil
Fabio Gomes Assis Junior
Department of Crop Protection, Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos), Sao Paulo State University, UNESP, Ilha Solteira 15385-000, SP, Brazil
Loane Dantas Krug
Department of Crop Protection, Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos), Sao Paulo State University, UNESP, Ilha Solteira 15385-000, SP, Brazil
Adriano Augusto de Paiva Custódio
Paraná Rural Development Institute, IDR—Paraná/IAPAR, Londrina 86047-902, PR, Brazil
Rui Pereira Leite Júnior
Paraná Rural Development Institute, IDR—Paraná/IAPAR, Londrina 86047-902, PR, Brazil
Paulo Eduardo Teodoro
Campus CPSC, Federal University of Mato Grosso do Sul, UFMS, Chapadão do Sul 79560-000, MS, Brazil
Bart Fraaije
National Institute of Agricultural Botany, NIAB, Cambridge CB3 0LE, UK
Paulo Cezar Ceresini
Department of Crop Protection, Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos), Sao Paulo State University, UNESP, Ilha Solteira 15385-000, SP, Brazil
Widespread resistance to QoIs, DMI and SDHIs fungicides has been reported for Brazilian populations of the wheat blast pathogen Pyricularia oryzae Triticum lineage (PoTl). A pre-existing resistance mechanism not associated with target site mutations has been indicated for resistance to DMIs and SDHIs, with strong indication that PoTl has multidrugresistance (MDR). Therefore, the main objective of this study was to test the hypothesis that resistance to DMI and SDHI fungicides detected in PoTl was due to efflux pump mediated MDR mechanism(s) by characterizing the sensitivity to antifungal efflux pump substrates. Four antifungal substrates were tested: tolnaftate (TOL), cycloheximide (CHX), rhodamine 6G (RH6G) and triphenyltin chloride (TPCL). TPCL and RH6G were considered the most relevant indicators for enhanced MDR activity. Among the 16 PoTl isolates tested, 9 were insensitive to TPCL, 1 to TOL, 16 to RH6G and 1 to CHX. The PoTl isolates were grouped into four distinct multidrug resistance phenotypes (MDRPs) based on resistance to combinations of fungicides and antifungal efflux pump substrates. Insensitivity to TPCL, RH6G and or TOL correlated well with DMI insensitivity, but MDR was not associated with SDHI resistance. The identification of multiple MDRP phenotypes associated with DMI resistance in our study warrants further research aimed at revealing the exact mechanisms of multidrug resistance in the wheat blast pathogen, including efflux pumps overexpression via transcriptomic analyses of differentially expressed genes; identification and discovery of mutations associated with changes in promoter regions or transcription factors of efflux transporters associated with multidrug resistance.
