RESUMO
BACKGROUND: Quinone outside inhibitor (QoI) fungicides have not been effective in controlling the wheat blast disease [Pyricularia oryzae Triticum lineage (PoTl)] in Brazil. The first report of resistance of PoTl to QoIs in this country occurred in 2015. This study aimed to test hypotheses about the changes in fitness parameters and competitive advantage of the QoI-resistant (R) PoTl isolate group compared to the sensitive (S) isolate group. Mycelial growth on PDA medium and in vivo conidial production, incubation period and disease severity were analyzed as fitness parameters. The competitive ability was measured on wheat leaves and heads inoculated with mixtures of R:S isolates at the following proportions: 0S:100R, 20S:80R, 50S:50R, 80S:20R, 100S:0R, and 0S:0R. RESULTS: The QoI-R isolate group had significantly higher fitness than the sensitive isolate group, considering both in vitro and in vivo parameters. The highest in vivo conidial production on wheat leaves and the highest leaf and head disease severity were detected when resistant strains were predominant in the isolate's mixtures (20S:80R or 0S:100R proportions), in the absence of fungicide pressure. Conidia harvested from wheat blast lesions on leaves inoculated with 20S:80R and 0S:100R mixtures were resistant to QoIs in vitro assays based on discriminatory doses of the fungicide. CONCLUSION: Therefore, QoI resistance facilitated a higher fitness and a competitive advantage in PoTl, which contrasts with the evolutionary theory that associates a fitness cost to fungicide resistance. We discuss the evolutionary and ecological implications of the higher fitness as found in the fungicide-resistant adapted populations of the wheat blast pathogen. © 2022 Society of Chemical Industry.
Assuntos
Fungicidas Industriais , Fungicidas Industriais/farmacologia , Triticum , Estrobilurinas/farmacologia , Farmacorresistência Fúngica , Doenças das Plantas , Esporos Fúngicos , BenzoquinonasRESUMO
Osteosarcoma (OSA) is the most common observed primary bone tumor of dogs. This retrospective study, carried out from January 2001 to June 2004, included a total of 50 dogs with appendicular OSA, 28 females and 22 males, diverse races, aged between 1 and 16 years old. Most of the dogs were Rottweiler race (16 dogs), aged between 5 and 9 years old and weighing between 28 and 43kg. Thirty-seven animals showed the tumor in thoracic members and the most affected regions were distal radius, distal radius and ulna (32%) and the proximal humerus (28%). To determine the diagnosis it was used fine needle aspiration cytology associated to histopathology (29 dogs). Metastasis were observed only in 2 animals at the moment of the medical visit. We can conclude that middle-aged dogs weighting more than 30kg are more predisposed to develop this tumor. Thoracic members are most affected. Pulmonary metastasis are rarely detected at the moment of the medical visit. Animals without treatment have evolution time and shorter survival after medical visit. The surgical intervention associate to chemotherapy provides a greater survival time.KEY WORDS: Appendicular osteossarcoma, retrospective study, dog.
O osteossarcoma (OSA) é o tumor ósseo primário mais observado em cães. Este estudo retrospectivo, realizado entre janeiro de 2001 a junho de 2004, incluiu um total de 50 cães com OSA apendicular, 28 fêmeas e 22 machos, de diversas raças, entre 1 e 16 anos. A maioria dos cães era da raça Rottweiler (16 cães), com idade entre 5 e 9 anos e peso entre 28 e 43kg. Trinta e sete animais apresentaram o tumor em membros torácicos, e as regiões distal de rádio, distal de rádio e ulna (32%) e proximal de úmero (28%) foram as mais acometidas. Para determinar o diagnóstico, empregou-se a citologia aspirativa com agulha fina (CAAF) associada à histopatologia (29 cães). Metástases no momento da consulta foram observadas apenas em dois animais. Conclui-se que cães de meia-idade e com peso superior a 30 kg são mais predispostos ao desenvolvimento desse tumor. Os membros torácicos são mais acometidos. Metástases pulmonares raramente são detectadas no momento da consulta. Animais sem tratamento apresentam tempo de evolução após a consulta e sobrevida mais curtas. A intervenção cirúrgica associada à quimioterapia proporciona maior tempo de sobrevida. PALAVRAS-CHAVES: Cão, estudo retrospectivo, osteossarcoma apendicular.
RESUMO
Osteosarcoma (OSA) is the most common observed primary bone tumor of dogs. This retrospective study, carried out from January 2001 to June 2004, included a total of 50 dogs with appendicular OSA, 28 females and 22 males, diverse races, aged between 1 and 16 years old. Most of the dogs were Rottweiler race (16 dogs), aged between 5 and 9 years old and weighing between 28 and 43kg. Thirty-seven animals showed the tumor in thoracic members and the most affected regions were distal radius, distal radius and ulna (32%) and the proximal humerus (28%). To determine the diagnosis it was used fine needle aspiration cytology associated to histopathology (29 dogs). Metastasis were observed only in 2 animals at the moment of the medical visit. We can conclude that middle-aged dogs weighting more than 30kg are more predisposed to develop this tumor. Thoracic members are most affected. Pulmonary metastasis are rarely detected at the moment of the medical visit. Animals without treatment have evolution time and shorter survival after medical visit. The surgical intervention associate to chemotherapy provides a greater survival time.KEY WORDS: Appendicular osteossarcoma, retrospective study, dog.
O osteossarcoma (OSA) é o tumor ósseo primário mais observado em cães. Este estudo retrospectivo, realizado entre janeiro de 2001 a junho de 2004, incluiu um total de 50 cães com OSA apendicular, 28 fêmeas e 22 machos, de diversas raças, entre 1 e 16 anos. A maioria dos cães era da raça Rottweiler (16 cães), com idade entre 5 e 9 anos e peso entre 28 e 43kg. Trinta e sete animais apresentaram o tumor em membros torácicos, e as regiões distal de rádio, distal de rádio e ulna (32%) e proximal de úmero (28%) foram as mais acometidas. Para determinar o diagnóstico, empregou-se a citologia aspirativa com agulha fina (CAAF) associada à histopatologia (29 cães). Metástases no momento da consulta foram observadas apenas em dois animais. Conclui-se que cães de meia-idade e com peso superior a 30 kg são mais predispostos ao desenvolvimento desse tumor. Os membros torácicos são mais acometidos. Metástases pulmonares raramente são detectadas no momento da consulta. Animais sem tratamento apresentam tempo de evolução após a consulta e sobrevida mais curtas. A intervenção cirúrgica associada à quimioterapia proporciona maior tempo de sobrevida. PALAVRAS-CHAVES: Cão, estudo retrospectivo, osteossarcoma apendicular.