Potential for Conidium Formation of Pyricularia oryzae in Lesions on Leaves and Panicles of Rice

1970 ◽  
Vol 60 (4) ◽  
pp. 608 ◽  
Author(s):  
Hajime Kato
Author(s):  
Марина Владиславовна Илюшко ◽  
Марина Викторовна Ромашова ◽  
Светлана Сергеевна Гученко

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.


Author(s):  
Warlyton Silva Martins ◽  
Cid Tacaoca Muraishi

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.


2004 ◽  
Vol 1 (3) ◽  
pp. 257-271 ◽  
Author(s):  
M. Namikoshi ◽  
H. Kobayashi ◽  
H. Liu ◽  
X. Yao ◽  
H. Zhang
Keyword(s):  

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ba Van Vu ◽  
Quyet Nguyen ◽  
Yuki Kondo-Takeoka ◽  
Toshiki Murata ◽  
Naoki Kadotani ◽  
...  

AbstractTransposable elements are common targets for transcriptional and post-transcriptional gene silencing in eukaryotic genomes. However, the molecular mechanisms responsible for sensing such repeated sequences in the genome remain largely unknown. Here, we show that machinery of homologous recombination (HR) and RNA silencing play cooperative roles in copy number-dependent de novo DNA methylation of the retrotransposon MAGGY in the fungusPyricularia oryzae. Genetic and physical interaction studies revealed thatRecAdomain-containing proteins, includingP. oryzaehomologs ofRad51, Rad55, andRad57, together with an uncharacterized protein, Ddnm1, form complex(es) and mediate either the overall level or the copy number-dependence of de novo MAGGY DNA methylation, likely in conjunction with DNA repair. Interestingly,P. oryzaemutants of specific RNA silencing components (MoDCL1andMoAGO2)were impaired in copy number-dependence of MAGGY methylation. Co-immunoprecipitation of MoAGO2 and HR components suggested a physical interaction between the HR and RNA silencing machinery in the process.


IMA Fungus ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ruilin Sun ◽  
Meifang Wen ◽  
Lianghuan Wu ◽  
Huahui Lan ◽  
Jun Yuan ◽  
...  

AbstractAspergillus flavus is a common saprophytic filamentous fungus that produces the highly toxic natural compound aflatoxin during its growth process. Synthesis of the aflatoxins, which can contaminate food crops causing huge losses to the agricultural economy, is often regulated by epigenetic modification, such as the histone acetyltransferase. In this study, we used Aspergillus flavus as an experimental model to construct the acetyltransferase gene rtt109 knockout strain (△rtt109) and its complementary strain (△rtt109·com) by homologous recombination. The growth of △rtt109 was significantly suppressed compared to the wild type (WT) strain and the △rtt109·com strain. The sclerotium of △rtt109 grew smaller, and the amount of sclerotia generated by △rtt109 was significantly reduced. The number of conidiums of △rtt109 was significantly reduced, especially on the yeast extract sucrose (YES) solid medium. The amount of aflatoxins synthesized by △rtt109 in the PDB liquid medium was significantly decreased We also found that the △rtt109 strain was extremely sensitive to DNA damage stress. Through the maize seed infection experiment, we found that the growth of △rtt109 on the surface of affected corn was largely reduced, and the amount of aerial mycelium decreased significantly, which was consistent with the results on the artificial medium. We further found that H3K9 was the acetylated target of Rtt109 in A. flavus. In conclusion, Rtt109 participated in the growth, conidium formation, sclerotia generation, aflatoxin synthesis, environmental stress response, regulation of infection of A. flavus. The results from this study of rtt109 showed data for acetylation in the regulation of life processes and provided a new thought regarding the prevention and control of A. flavus hazards.


2021 ◽  
Vol 9 (7) ◽  
pp. 1441
Author(s):  
Van Bach Lam ◽  
Thibault Meyer ◽  
Anthony Arguelles Arias ◽  
Marc Ongena ◽  
Feyisara Eyiwumi Oni ◽  
...  

Rice monoculture in acid sulfate soils (ASSs) is affected by a wide range of abiotic and biotic constraints, including rice blast caused by Pyricularia oryzae. To progress towards a more sustainable agriculture, our research aimed to screen the biocontrol potential of indigenous Bacillus spp. against blast disease by triggering induced systemic resistance (ISR) via root application and direct antagonism. Strains belonging to the B. altitudinis and B. velezensis group could protect rice against blast disease by ISR. UPLC–MS and marker gene replacement methods were used to detect cyclic lipopeptide (CLiP) production and construct CLiPs deficient mutants of B. velezensis, respectively. Here we show that the CLiPs fengycin and iturin are both needed to elicit ISR against rice blast in potting soil and ASS conditions. The CLiPs surfactin, iturin and fengycin completely suppressed P. oryzae spore germination resulting in disease severity reduction when co-applied on rice leaves. In vitro microscopic assays revealed that iturin and fengycin inhibited the mycelial growth of the fungus P. oryzae, while surfactin had no effect. The capacity of indigenous Bacillus spp. to reduce rice blast by direct and indirect antagonism in ASS conditions provides an opportunity to explore their usage for rice blast control in the field.


2021 ◽  
Vol 22 (7) ◽  
pp. 3731
Author(s):  
Andrea Kunova ◽  
Luca Palazzolo ◽  
Fabio Forlani ◽  
Giorgia Catinella ◽  
Loana Musso ◽  
...  

The increasing emergence of fungicide-resistant pathogens requires urgent solutions for crop disease management. Here, we describe a structural investigation of new fungicides obtained by combining strobilurin and succinate dehydrogenase inhibitor pharmacophores. We identified compounds endowed with very good activity against wild-type Pyricularia oryzae, combined in some cases with promising activity against strobilurin-resistant strains. The first three-dimensional model of P. oryzae cytochrome bc1 complex containing azoxystrobin as a ligand was developed. The model was validated with a set of commercially available strobilurins, and it well explains both the resistance mechanism to strobilurins mediated by the mutation G143A and the activity of metyltetraprole against strobilurin-resistant strains. The obtained results shed light on the key recognition determinants of strobilurin-like derivatives in the cytochrome bc1 active site and will guide the further rational design of new fungicides able to overcome resistance caused by G143A mutation in the rice blast pathogen.


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