Fungicide resistance in Pyricularia oryzae populations from southern and northern Brazil and evidence of fitness costs for QoI-resistant isolates

The changes in fungicide resistance frequency and population structure of the rice blast fungus Pyricularia oryzae were monitored after the discontinuance of melanin biosynthesis inhibitor targeting scytalone dehydratase (MBI-D) fungicides use in Saga Prefecture, Japan. After discontinuance in 2003, the frequency of resistant isolates decreased from 71.8% in 2002 to 25% in 2003, and became undetectable in 2007. The initial marked decrease was due to a decline of isolates possessing the predominant haplotype, although the haplotypic diversity among resistant isolates remained high from 2003 to 2005. These results revealed that resistant isolates were less fit in comparison with sensitive isolates in the absence of MBI-D fungicide pressure under field conditions. Pairwise FST values indicated that the change in population structure after MBI-D discontinuance was explainable by a rapid change in the proportions of resistant and sensitive subpopulations. Depending upon the existence of fitness cost and rapid changes in population structure, it may be possible to reintroduce MBI-D fungicides in areas where resistance has already developed, although we speculate that fitness cost related to MBI-D resistance may be small based on our present results and previous findings.

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Soft selective sweeps in fungicide resistance evolution: recurrent mutations without fitness costs in grapevine downy mildew

Molecular Ecology ◽

10.1111/mec.14006 ◽

2017 ◽

Vol 26 (7) ◽

pp. 1936-1951 ◽

Cited By ~ 24

Author(s):

Chloé E. L. Delmas ◽

Yann Dussert ◽

Laurent Delière ◽

Carole Couture ◽

Isabelle D. Mazet ◽

...

Keyword(s):

Downy Mildew ◽

Fungicide Resistance ◽

Selective Sweeps ◽

Fitness Costs ◽

Grapevine Downy Mildew ◽

Resistance Evolution ◽

Recurrent Mutations ◽

Soft Selective Sweeps

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Fitness Costs and Benefits of Female Song

10.3389/978-2-88945-258-3 ◽

2017 ◽

Cited By ~ 2

Keyword(s):

Costs And Benefits ◽

Fitness Costs ◽

Female Song

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Молекулярное маркирование генов устойчивости к пирикуляриозу в сортах риса дальневосточной селекции

Аграрная Россия ◽

10.30906/1999-5636-2020-10-30-33 ◽

2020 ◽

pp. 30-33

Author(s):

Марина Владиславовна Илюшко ◽

Марина Викторовна Ромашова ◽

Светлана Сергеевна Гученко

Keyword(s):

Oryza Sativa ◽

Oryza Sativa L ◽

Pyricularia Oryzae

С помощью молекулярно-генетических маркеров изучены 13 сортов риса (Oryza sativa L.), зарегистрированных в Государственном реестре селекционных достижений по дальневосточной зоне, и 1 перспективный сорт на наличие 6 генов устойчивости к пирикуляриозу риса — Pi-2, Pi-9, Pi-b, Pi-z(t), Pi-1 и Pi-ta2, наиболее актуальных для региона. В 4 сортах не обнаружено генов резистентности к пирикуляриозу. В 8 сортах идентифицировано по 1 гену устойчивости — Pi-2 и Pi-ta2. В 1 сорте (Садко) выявлено 2 изученных гена — Pi-z(t) и Pi-ta2. Изученные 8 сортов риса используют для технологии пирамидирования генов в селекции на устойчивость риса к пирикуляриозу для дальневосточной зоны рисосеяния. Выявленные гены резистентности риса к Pyricularia oryzae Cav. могут служить объективным идентификатором при паспортизации изученных сортов. Обсуждаются причины потери иммунности сортов и необходимости молекулярно-генетического сопровождения процесса семеноводства риса.

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The Order in Which Antibiotics are Administered Affects the Fitness Costs of Adherent-Invasive E. coli (AIEC) Strains

10.31219/osf.io/46fae ◽

2019 ◽

Author(s):

Jordan B Gregg

Keyword(s):

Crohn’S Disease ◽

Crohn's Disease ◽

Combination Therapy ◽

Agar Plate ◽

Sequential Therapy ◽

Negative Control ◽

Clinical Settings ◽

Fitness Costs ◽

Inflammatory Gene Expression ◽

E Coli

AIEC-LF82 is a strain of bacteria that is surmised to have a role in causing IBD and Crohn’s disease by activating pro-inflammatory gene expression in organisms. Using antibiotics via combination therapy has been a technique used in clinical settings in an attempt to treat the strains, however, the attempts have not been that effective nor efficient in terms of completely halting the growth and colonization of AIEC to treat IBD and Crohn's disease patients. Research has shown that regarding hindering or preventing the colonization bacterial colonies, sequential therapy tends to be more effective and time-efficient than combination therapy, with fewer adverse effects. To test if this is also the case with the AIEC-LF82 strain of bacteria, I first tested AIEC’s response to combination therapy using the Penicillin-Streptomycin, Kanamycin-Chloramphenicol, antimicrobial peptide (AMP), Kanamycin, SPE phase and LB agar plates, all of which were experimental plates other than the LB agar plate that acted as the negative control. I then tested AIEC-LF82’s response to sequential therapy using the LB+ Kan + Spe, LB + AMP + Spe, LB+ Kan/Cam + Spe, LB + P/S + Spe, LB + P/S + Kan and LB + P/S + AMP and one LB agar plate acting as the negative control. The only differences between sets a and b were the order in which antibiotics were administered in the six aforementioned treatment sets. Ultimately, I found that set b of sequential therapy, strong-weak antibiotic treatments, was the most effective treatment but that set a regarding sequential therapy was actually the least effective of all of the treatments. In conclusion, using strong-weak sequential antibiotic therapy treatments appears to be a potentially promising option to treat patients suffering from Crohn's disease and IBD.

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Fungicide resistance in field crops

10.31274/icm-180809-151 ◽

2014 ◽

Author(s):

Daren Mueller

Keyword(s):

Fungicide Resistance ◽

Field Crops

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ASPECTOS BIOMÉTRICOS, GRAU DE UMIDADE EM SEMENTES DE SUCUPIRA E DETERMINAÇÃO DO EFEITO FUNGITÓXICO DO SEU ÓLEO ESSENCIAL

Revista Integralização Universitária ◽

10.31501/1982-9280.2019v13n20p.17-24 ◽

2019 ◽

pp. 17-24

Author(s):

Warlyton Silva Martins ◽

Cid Tacaoca Muraishi

Keyword(s):

Pyricularia Oryzae ◽

Didymella Bryoniae ◽

Fusarium Subglutinans

A busca por métodos naturais que viabilizam a eficiência da atividade biológica sobre vários microrganismos vem sendo destaque no cenário atual. A exploração da atividade biológica de compostos secundários presentes no extrato bruto ou óleos essenciais de plantas pode constituir, ao lado da indução da resistência, em uma forma efetiva de controle de doenças em plantas cultivadas. Diante disso, o presente estudo teve por objetivo avaliar a eficiência do óleo essencial de sucupira em suas propriedades de rendimento, bem como sua atividade biológica antifúngica sobre determinados patógenos que afetam culturas promissoras no Estado do Tocantins. Instalou-se o experimento no Campus de Ciências Agrárias da Faculdade Católica do Tocantins no laboratório de Bromatologia e Fitopatologia, para extração do óleo essência, avaliação do grau de umidade e biometria de sementes, obtenção dos fitopatógenos e avaliação dos efeitos fungitóxicos do óleo essencial. O delineamento experimental utilizado foi inteiramente casualizado com quatro tratamentos e cinco repetições. Os tratamentos, adicionados ao meio de cultura, após a autoclavagem e o resfriamento, foram as seguintes: sucupira (BDA + 25% de extrato de sucupira + 0,016% de polissorbato), sucupira (BDA + 50% de extrato de sucupira + 0,016% de polissorbato), sucupira (BDA + 75% de extrato de sucupira + 0,016% de polissorbato), sucupira (BDA + 100% de extrato de sucupira + 0,016% de polissorbato) e testemunha (BDA). Os resultados foram submetidos ao teste Tukey (5%) de probabilidade. O óleo essencial de sucupira inibiu o desenvolvimento micelial de Fusarium subglutinans, Sclerotinia sclerotiurum, Didymella bryoniae, Pyricularia oryzae.

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