Pyricularia Oryzae Cav Research Articles

Studying the Genetic Diversity of the Rice Break Cause <i>Pyricularia oryzae</i> Cav. on the Complex of Molecular and Morphological Features

On the basis of molecular genetic approaches, the study of the biodiversity of the phytopathogenic fungus Pyricularia oryzae Cav. in the south of Russia and a classification of the morphological and cultural characteristics of the pathogen was carried out. For 2020–2022 monitoring was carried out and 24 strains of the pathogen were isolated from the affected herbarium material collected from the fields of five ecological rice growing zones of the Krasnodar Territory (Krasnoarmeisky, Kalininsky, Abinsky, Slavyansky districts, Krasnodar). Using the multiplex PCR system developed by us based on fragment analysis, five genotypes were identified among the studied Pyricularia oryzae Cav. strains over the entire period of the project, each of which is characterized by a unique genetic profile. Compiled their “DNA passport”. The studied isolates of the causative agent of blast were characterized by morphological and cultural characteristics. Six morphotypes of the pathogen have been identified.

Studying the Genetic Diversity of the Cause of Rice Blast Pyricularia oryzae Cav. on the Set of Molecular and Morphological Features

Studying the Genetic Diversity of the Cause of Rice Blast Pyricularia oryzae Cav. on the Set of Molecular and Morphological Features

Microscopic and molecular studies in the biological control of rice blast caused by Pyricularia oryzae with Bacillus sp. BMH under greenhouse conditions

Rice (Oryza sativa L.) feeds around half of humanity mainly in Asia, South America, and Africa. Pyricularia oryzae Cav. (syn. Magnaporthe oryzae Couch) is the causative agent of the most devastating disease of rice worldwide. The purpose of this study was to evaluate the efficiency of the selected Bacillus sp. strain BMH in relation to its antagonistic attributes against P. oryzae as well as rice cultivar BRS.MG Caçula growth promotion, productivity, and its ability to colonize tissues and induce resistance in plants using microscopy, genes expression, and pot assay under greenhouse conditions. The soil and seedlings were inoculated with Bacillus sp. BMH and the seedlings were sprayed with P. oryzae isolate A10965. The severity evaluation and microscopic analysis showed that BMH was able to reduce rice blast severity with 53.12%, 50%, and 37.5% for soil inoculation, preventive control, and the mixture of pathogen-BMH treatments respectively at 28 DAI. Rice plants were higher following the Bacillus sp. BMH inoculation in soil with 25.73 cm compared to the control treatment with 21.93 cm at 63 days after sowing (DAS). Likewise, the number of tillers was higher with 12.6 for BMH against 9.13 for control as well as grain weight with 10.17 g for BMH treatments against 7.14 g for untreated one. BMH enhanced plant growth promotion (PGP) and production, which illustrates its potential use as a biocontrol agent. The Confocal Laser Microscopy (CLM) and Scanning Electron microscopy (SEM) showed the colonization of rice root vascular tissues as well as foliage by Bacillus sp. BMH cells, which indicates its endophytic potential. In the molecular study, the expression of genes responsible for conferring resistance to the blast was studied upon colonization of the plants by beneficial and pathogenic microbe’s invasion, namely ALD1, OsPR1a, OsPR1b, OsGLN1, OsWRKY28. Soil inoculation with BMH or sprayed on the surface of leaves resulted in the stimulation of rice defense mechanisms against blast disease by upregulating the rice β-1,3-glucanases (OsGLN1) and OsPR1a, which are thought to be involved in plant normal growth and development, playing a direct role in defense against fungi, and other stressors. The results obtained in this research demonstrate the beneficial interaction between rice plants and BMH, as well as the blast management strategy, that could help to reduce dependence on fungicides and contribute to the sustainability of rice cropping.

Effectiveness of Endophyte Fungi as a Controling of Blast Disease on Paddy (Oryza sativa)

The research was conducted to determine: endophyte fungi on paddy plant (Oryza sativa); the antagonistic percentageof endophyte fungi against to Pyricularia oryzae Cav.; and the antagonistic mechanisms between each endophyte fungi to Pyricularia oryzae Cav..The experiment was conducted at the Integrated Laboratory of Agriculture Faculty of Mulawarman University, and samples of infected plant was collected from Sungai Kapih village, Sambutan Sub-district of Samarinda City The experimental treatments was arranged in a Completely Randomized Design (CRD), consisting of four treatments and each treatment was repeated ten times.The results showed that endophyte fungi isolated from the paddy plant (Oryza sativa) were Trichoderma sp., Rhizopus sp., Gliocladium sp., and Penicillium sp. The competition was proved as the antagonistic mechanism of Rhizopus sp. against, while antibiosis was proved as the antagonistic mechanism of Penicillium sp. against. Trichoderma sp. and Gliocladium sp. against were shown to have two antagonistic mecanism are competition and parasitsm. The capability of endophyte fungi as a biological agents to compete those P. Oryzae was express an antagonism capacity differences, the highest rate of inhibition was occurred on the P. oryzae vs Gliocladium sp.(78,96%).
 Keywords :Pyricularia oryza Cav., Endophyte fungi, Antagonistic mechanim

Resistance of Far Eastern Rice Oryza Sativa L. Varieties and Competitive Testing Samples to Pyricularia Oryzae Cav.

Resistance of Far Eastern Rice Oryza Sativa L. Varieties and Competitive Testing Samples to Pyricularia Oryzae Cav.

Çeltik yanıklığı hastalığının görüntü işleme teknikleri kullanılarak tespit edilmesi

In rice plant, accurate and timely detection of diseases helps to start agricultural practices on time and thus reduces economic losses significantly. For this purpose, image processing techniques were used to identify and classify the rice leaf blight disease ( Pyricularia oryzae Cav.). In image processing, a clustering method was used for the segmentation of the diseased part, the non-diseased part and the background. Images of rice leaf blight disease were taken both from the ground and with the aid of a drone. Levenberg-Marquardt training algorithm was preferred in artificial neural networks model. While the RMS, R 2 and error values of the test data of MEITG proposed for identification were 0.000017, 0.9999 and 0.019%, respectively, they were found as 0.000007, 0.9999 and 0.002% for MERITD. The MCITG and MCRITD models presented for classification were found to have classification success rates of 92.2 percent and 100 percent, respectively. The results obtained for the identification and classification of rice leaf blight disease show the feasibility and effectiveness of the proposed model.

Effect of Streptomyces xantholiticus on Rice Blast Disease Reduction and Enzyme Activity

The rice blast infection triggered by Pyricularia oryzae Cav. is a grave issue restraining rice yields globally. Biological regulation has been seen as an encouraging option to such chemical fungicides. The biological control proficiency of 24 isolates of Streptomyces against P. oryzae (KT693184.1) has been examined. Analysis of defense enzymes such as polyphenol, peroxidase (PO), and total protein and phenol content was performed. The Streptomyces isolate that was determined to have maximum effectiveness was determined to be Streptomyces xantholiticus. The sequence was sent to the NCBI vide accession number MW029942. The S. xantholiticus isolate inhibited P. oryzae 92% using dual culture tests. The greenhouse experiments showed that the disease gravity in rice plants with S. xantholiticus isolate was considerably lower compared to plants sans the treatment. The S. xantholiticus isolate was analyzed for its effects concerning the activity of polyphenol and Po enzymes as well as the total protein content present in rice leaves under greenhouse conditions in both presence and absence of P. oryzae. It was found that rice species treated with the S. xantholiticus isolate had enhanced resistance to the rice blast pathogen along with increasing activity levels of the polyphenol and PO enzymes. There was a direct impact on pathogen growth along with the defense response triggered in the plants as a result of the treatment.

Photoperiod Following Inoculation of Arabidopsis with Pyricularia oryzae (syn. Magnaporthe oryzae) Influences on the Plant-Pathogen Interaction.

In plant–pathogen interactions, a proper light environment affects the establishment of defense responses in plants. In our previous experiments, we found that nonhost resistance (NHR) to Pyricularia oryzae Cav. in Arabidopsis thaliana (L.) Heynh. (Arabidopsis), in diurnal conditions, varies with the inoculation time. Moreover, we indicated that the circadian clock plays an important role in regulating time-of-day differences in NHR to P. oryzae in Arabidopsis. However, the involvement of photoperiod in regulating NHR was still not understood. To determine the photoperiod role, we performed the experiments in continuous light and darkness during the early Arabidopsis–P. oryzae interaction. We found that the light period after the inoculation in the evening enhanced the resistance to penetration. However, the dark period after the inoculation in the morning suppressed the penetration resistance. Furthermore, the genetic analysis indicated that jasmonic acid, reactive oxygen species, and tryptophan-derived metabolite(s) contribute to the photoperiod regulation of NHR in Arabidopsis. The present results denote that photoperiod plays an important role in regulating time-of-day differences in NHR to P. oryzae in Arabidopsis.

Studying of Cultural Properties of Pyricularia oryzae Cav. Strains in the South of Russia

This article presents the results of the development of a methodology for describing the main morphological and cultural traits of the Pyricularia oryzae Cav. strains widespread in the south of Russia. At the same time, the types of traits are identified and listed, which make it possible to unambiguously determine the uniqueness and variety of the pathogen. The relationships and patterns established using cluster and statistical analysis make it possible to identify the conditions for the development of a pathogen that determine its predominant forms. Thus, research shows that leaf forms of P. oryzae strains isolated from rice plants with leaf form of blast disease have an equally directional growth pattern of a colony with a felt structure, and strains isolated from neck-affected plant form often produce a zone of a colony with a clumpy structure. The classification of cultural traits will make it possible to obtain scientifically grounded and comparable data that can be used in the analysis of the interaction of P. oryzae strains with rice plants on various varieties and in various agro-technological conditions in order to improve and rationalize agricultural activities. The study opens up the possibility of using data in breeding, making it possible to identify forms of a pathogen that infect certain varieties.

Молекулярное маркирование генов устойчивости к пирикуляриозу в сортах риса дальневосточной селекции

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.

Marker assisted rice breeding for resistance to biotic and abiotic stressors

Due to the fact that blast (causative agent – Pyricularia oryzae Cav.) is considered to be one of the harmful diseases of rice around the world, weeds compete with the crop for light, mineral nutrition and space, the accelerated development of resistant genotypes for these stressors is very relevant. The use of modern biotechnological approaches (molecular marking) is promising and especially in demand in breeding rice varieties of a new generation. This article presents the results on the introduction and pyramiding in the same genotype blast resistance genes Pi-1, Pi-2, Pi-33, Pi-ta, Pi-b, Pi-40 and the gene for tolerance to prolonged flooding Sub 1A, as a weed control factor, based on domestic rice varieties Flagman, Snezhinka, Novator, Boyarin, as well as large-grain lines, with a short growing season VNIIR5242, KP-25-14, KP-163 and VNIIR9678. As a result of the volumetric work using marker control of target genes in the genotypes of hybrid plants, 4 modern varietal samples and more than 400 backcross self-pollinated rice lines with introduced and pyramided blast resistance genes, as well as backcross self-pollinated lines with Pi and Sub1A genes, were obtained. These plants are adapted for cultivation in the south of Russia, have a duration of 115-117 days, a height of 87-100 cm, a mass of 1000 grains – 30 or more grams, a yield of 8.5 – 11 t/ha, which is significantly higher than that of the standard variety Flagman.

Antifungal Potency of Secondary Metabolites Produced by Endophytic Bacteria against Pathogenic Fungi Pyricularia oryzae Cav.

Blast disease caused by Pyricularia oryzae Cav. is one of the most important diseases on rice. One of the alternative controlling methods in P. oryzae is biological control through the utilization of secondary metabolites produced by endophytic bacteria. The study aimed to determine the antifungal potency of secondary metabolites produced by rice endophytic bacteria against P. oryzae. The experiment was conducted using 9 endophytic bacteria isolated rice (Os1, Os2, Os3, Os4, Os5, Os6, Os7, Os8, and Os10). Each isolates were grown in ISP2 liquid media and the secondary metabolites compounds were extracted using two different solvents; methanol and ethyl acetate : methanol (4:1) (v/v). The effect of secondary metabolites was tested using agar well diffusion method. The results demonstrated that the secondary metabolites extracted by both solvents have antifungal effect on the growth of P. oryzae. The highest growth inhibition was shown by secondary metabolites extracted by ethyl acetate : methanol (4:1) from Os1 (42%) and Os3 (39%). Antifungal activity of the secondary metabolites was indicated by the formation of clear zone. HPLC (High Performance Liquid Chromatography) analysis showed the differences of peaks and retention time between secondary metabolites produced by Os1 and Os3 which has antifungal activity and secondary metabolites produced by Os10 that did not show the antifungal activity.

СОЗДАНИЕ СОРТОВ РИСА, УСТОЙЧИВЫХ К ПИРИКУЛЯРИОЗУ, НА ОСНОВЕ ПРИМЕНЕНИЯ ДНК-ТЕХНОЛОГИЙ

Diseases of agricultural crops are the main reason for decreased yield and quality of product. Blast (causative agent: Pyricularia oryzae Cav.) is the most harmful disease on rice fields. Economic damage caused by the pathogen is significant in all areas of the world’s rice cultivation. The most effective, economically justified and environmentally friendly strategy for combating it is development of resistant varieties. The application of DNA markers linked to loci of resistance to blast is relevant in this area. This makes it possible to significantly shorten the breeding process and promptly develop disease-resistant rice forms. In this regard, the aim of the work was to develop source material for breeding as well as highly productive rice varieties and lines with genes of resistance to blast based on the use of molecular marking method. To achieve this goal, we have launched a program since 2007 aimed at introduction of the blast resistance Pi-ta gene, effective for the south of Russia, into the domestic rice cultivar Flagman. After a number of recurrent crosses, the breeding material was obtained, which was studied for economically valuable traits in breeding nurseries. As a result of evaluation and rigorous discarding as well as according to the results of a phytopathological test for blast resistance, several lines were identified that have high indicators of milled rice quality, resistance to blast, yield and economically valuable traits. Rice accession KP-171-14 with the Pi-ta gene, adapted to growing conditions in the south of Russia, resistant to the Krasnodar population of P. oryzae, and having high yield and grain quality, in 2017 was submitted for State Variety Trials (SVT) under the name Alyans. Accessions KP-30 and KP-23 are tested for economically valuable traits and disease resistance in competitive variety trials. The best accession will be submitted to SVT. The introduction and cultivation of such varieties will reduce the use of chemical protection products, obtain environmentally friendly agricultural products and avoid contamination of grain ecosystems

МОРФОЛОГО-КУЛЬТУРАЛЬНЫЕ СВОЙСТВА И ПАТОГЕННОСТЬ ПОПУЛЯЦИИ ВОЗБУДИТЕЛЯ PYRICULARIA ORIZAE CAV. НА РАЙОНИРОВАННЫХ СОРТАХ РИСА

МОРФОЛОГО-КУЛЬТУРАЛЬНЫЕ СВОЙСТВА И ПАТОГЕННОСТЬ ПОПУЛЯЦИИ ВОЗБУДИТЕЛЯ PYRICULARIA ORIZAE CAV. НА РАЙОНИРОВАННЫХ СОРТАХ РИСА

Efficient Synthesis and Bioactivity of Novel Triazole Derivatives.

Triazole pesticides are organic nitrogen-containing heterocyclic compounds, which contain 1,2,3-triazole ring. In order to develop potential glucosamine-6-phosphate synthase (GlmS) inhibitor fungicides, forty compounds of triazole derivatives were synthesized in an efficient way, thirty nine of them were new compounds. The structures of all the compounds were confirmed by high resolution mass spectrometer (HRMS), 1H-NMR and 13C-NMR. The fungicidal activities results based on means of mycelium growth rate method indicated that some of the compounds exhibited good fungicidal activities against P. CapasiciLeonian, Sclerotinia sclerotiorum (Lib.) de Bary, Pyricularia oryzae Cav. and Fusarium oxysporum Schl. F.sp. vasinfectum (Atk.) Snyd. & Hans. at the concentration of 50 µg/mL, especially the inhibitory rates of compounds 1-d and 1-f were over 80%. At the same time, the preliminary studies based on the Elson-Morgan method indicated that the compounds exhibited some inhibitory activity toward glucosamine-6-phosphate synthase (GlmS). These compounds will be further studied as potential antifungal lead compounds. The structure-activity relationships (SAR) were discussed in terms of the effects of the substituents on both the benzene and the sugar ring.

Detection of Pyricularia oryzae Based on Indirect ELISA Using Germinating Conidia as the Antigen Preparation

One of the most destructive fungal diseases in rice crop in Malaysia is the Rice blast disease or Penyakit Karah, which is caused by Pyricularia oryzae Cav. (previously known as Magnoporthe grisea). The disease can cause a loss of yield of more than 50 percent. In this study a sensitive indirect ELISA method was developed for the detection of Pyricularia oryzae through an indirect ELISA method using rabbit polyclonal antibody against different concentrations of Pyricularia oryzae conidia to give seven calibration standard points ranging from 1×101 to 1×109 conidia/mL. The calibration curve shows a typical sigmoidal curve and the fitting of the curve was based on the four-parameter logistic equation. The calculated LOD value was 21.60 conidia/mL (95% confidence interval, 11.63 to 31.57 conidia/mL) with a good correlation coefficient value of 0.999 indicating the model fit the experimental data in an excellent manner. The sensitivity was comparable to another published work which claimed to be the most sensitive to date. This indicate that the current developed method can be utilized in the future as a sensitive method for the rapid and simple detection of this pathogen.

Biocontrol Potential of Endophytic Bacteria Isolated from Healthy Rice Plant against Rice Blast Disease (Pyricularia oryzae Cav.)

Isolation was attempted to collect endophytic bacteria as potential biocontrol agents against rice blast disease (Pyricularia oryzae Cav.). The disease is one of major threats in rice production as it can cause 100% yield loss. Concern on the environment and human health has led to the searching of alternative controlling method to replace the commonly used pesticide-based method. Endophytic bacteria are bacteria that have intimate relationship with their host without inducing any pathogenic symptom. The use of endophytic microbial as biocontrol agent has its own advantages as the microbes are more easily to adapt to the environment needed by the host plant. We evaluated endophytic bacteria isolated from healthy rice plants and tested for their potential biocontrol activity using dual culture assay. Ten isolates were found to inhibit the growth of P. oryzae of more than 50%. Microscopic observation showed that they were able to cause the mycelia malformation of P. oryzae. Further work is currently in progress to determine their effectiveness in the pot trial. Keywords: Endophytic bacteria; Pyricularia oryzae; biocontrol.

English

An investigation was carried out at two locations during Kharif 2007 - 2008, to evaluate the efficacy of fungicides, bio-agent and botanicals for the management of rice blast caused by Pyricularia oryzae Cavara, on highly susceptible cv. Pankhali. All the spray treatments proved effective and reduce leaf and neck blast intensity and significantly increased the yield parameters. Among the treatments, tricyclazole proved significantly superior over rest of the treatments for all the attributes, viz., leaf blast, neck blast, grain, straw yield and 1000 grain wt. at both the locations and in pooled analysis. The next effective treatment was Pseudomonas fluorescens but it was at par with iprobenfos. Key words: Blast, Pyricularia oryzae Cav, fungicides, bio-agent, botanicals.

Design, synthesis and bioactivity of novel glycosylthiadiazole derivatives.

A series of novel glycosylthiadiazole derivatives, namely 2-phenylamino-5-glycosyl-1,3,4-thiadiazoles, were designed and synthesized by condensation between sugar aldehydes A/B and substituted thiosemicarbazide C followed by oxidative cyclization by treating with manganese dioxide. The original fungicidal activities results showed that some title compounds exhibited excellent fungicidal activities against Sclerotinia sclerotiorum (Lib.) de Bary and Pyricularia oryzae Cav, especially compounds F-5 and G-8 which displayed better fungicidal activities than the commercial fungicide chlorothalonil. At the same time, the preliminary studies based on the Elson-Morgan method indicated that many compounds exhibited some inhibitory activity toward glucosamine-6-phosphate synthase (GlmS). The structure-activity relationships (SAR) are discussed in terms of the effects of the substituents on both the benzene and the sugar ring.

Rice blast-mycoflora, symptomatology and pathogenicity

Rice (Oryza sativa L.) is the second most important cereal crop of the world as well as of Pakistan. Rice blast caused by a Magnaporthe oryzae (syn: Pyricularia oryzae Cav.) is an infectious fungal disease which is distributed worldwide and prevailing in more than 85 countries of the world. Therefore, present studies were carried out to isolated different fungi associated with seeds and leaves of commercially grown rice varieties and to test the pathogenicity of predominantly isolated species. Seven fungi namely Magnaporthe oryzae, Curvularia lunata, Helminthosporium oryzae, Fusarium moniliforme, Alternaria alternata, Nigrospora oryzae and Aspergillus niger were isolated from seeds and affected leaves of five rice varieties viz., IRRI-6, IRRI-8, DR-82, KS-282 and Shua. N. oryzae was isolated only from IRRI-6 and IRRI-8 rice varieties. Among these fungi, M. oryzae was predominantly isolated both from seeds and leaves of the rice varieties studied. Rice variety IRRI-6 followed by KS-282 appeared as most susceptible rice cultivars to rice blast fungus. M. oryzae was detected with highest frequency from leaves and seeds of IRRI-6. All other fungi were isolated either occasionally or with low frequency. Pathogenicity test of M. oryzae conducted on apparently most susceptible variety IRRI-6 has confirmed the pathogenic nature of the fungus. Plant growth was significantly decreased in inoculated plants as compared to un-inoculated plants. Moreover, typical rice blast disease symptoms were also produced in inoculated plants.