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Insertional mutagenesis to identify novel determinants of pathogenicity in Magnaporthe oryzaeIslam, Muhammad Sougatul January 2012 (has links)
Rice blast disease is caused by the filamentous fungus Magnaporthe oryzae and is the most destructive disease of cultivated rice. It was the first plant pathogenic fungus to have its genome sequence published which opened up the opportunities to discern the principal genetic components that confer pathogenicity on the fungus. The availability of the genome sequence has also presented fresh challenges in terms of converting sequence data into meaningful biological information. Functional genomics studies involve the generation of genome-wide mutant collections and comprehensive screens with potential to identify novel pathogenicity determinants. In this study I utilized Agrobacterium tumefaciens mediated random insertional mutagenesis to study the infection mechanism of M. oryzae. A collection 10,200 M. oryzae T-DNA insertion mutants were generated as part of this study and pathogenicity was assayed by high-throughput disease screening. From the primary qualitative screening I obtained 200 mutants that were reduced or lacking in pathogenicity. Quantitative re-screening allowed selection of 71 T-DNA mutants, including 9 non-pathogenic and 63 reduced virulence mutants exhibiting at least a 50% reduction in disease symptoms. Finally, we selected 8 non-pathogenic mutants for detailed phenotypic and gene functional analysis. A novel approach was used to retrieve T-DNA tagged genes from mutants of interest. Next generation DNA sequencing (NGS) was used to retrieve T-DNA flanking sequences in a high-throughput manner. The efficiency of NGS to facilitate the high-throughput large scale insertional mutagenesis was therefore demonstrated. Out of 8 selected mutants, I identified three novel genes that putatively encode a transcription factor, a PH domain containing signalling protein and a MAP kinase. I also provided evidence that, MGG_05343 is a functional C6 zinc finger transcription factor involved in conidiogenesis. The PH domain containing protein MGG_12956 is involved in vegetative growth, condiogenesis and virulence. The novel kinase MGG_15325 is a S. cerevisiae IME2 homolog that belongs to the Ime2 class of non-classical MAP kinase subfamily. Intriguingly, M. oryzae IME2 seems to have an essential role in growth in planta because the mutant was able to penetrate and colonize plant tissue but failed to cause necrotic rice blast lesions. Identification of these novel genes will allow us greater insight into the processes required for condiogenesis, vegetative and invasive growth and a more integrated understanding of the post-penetration phases of plant tissue colonization. Interestingly, I identified two mutants tagged with T-DNA insertion in the autophagy genes ATG2 and ATG3, reaffirming the importance of infection-associated autophagy in plant infection by M. oryzae and we characterized the ATG3 gene. In addition, I generated a resource of 63 unidentified T-DNA mutants which can potentially lead to identification of more novel determinants of pathogenicity in rice blast disease.
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Developing models to predict favorable environments for rice blastCalvero, Silvino B. 26 April 1994 (has links)
Statistical analyses were used to develop predictive
models of rice blast and to relate the favorability of
environment to disease incidence and severity on different
rice cultivars at five sites in Asia. The WINDOW PANE
program was used to search for weather factors highly
correlated with blast. Stepwise and r-square linear
regression procedures were then applied to generate the
predictive models at each site. Models developed at Icheon,
South Korea included relative humidity and rainfall factors
as the most important predictors of disease. Temperature,
rainfall, wind speed, and relative humidity factors were
components of models at Cavinti and the IRRI blast nursery
in the Philippines. Rainfall, temperature, and solar
radiation factors were important at Gunung Medan and
Sitiung, Indonesia. Model validation was done to verify
accuracy of models for predictions. Model predictions were
also used to determine the effects on blast of sowing time,
nitrogen amount, and increase in temperature. Limitations of
the models are discussed.
Path coefficient analysis was used to identify direct
and indirect influences exerted by weather factors on blast.
The largest direct influence on disease was exerted by
humidity factors at Icheon; temperature, rainfall, and wind
speed factors at Cavinti; temperature and humidity factors
at IRRI; rainfall factors at Gunung Medan; and temperature
factors at Sitiung. Although path coefficient values (Py)
were estimated from the decomposition of correlation
coefficients, factors that had a high correlation with
disease parameters did not always give high Py.
Multivariate analysis was used to determine the effects
of sowing times on proneness of tropical rice to blast.
Cluster analysis of 24 hypothetical sowing months at
Cavinti, the IRRI blast nursery, and Sitiung sites revealed
three blast proneness groups. Principal component analysis
showed that IR50 cultivar would be susceptible at Cavinti at
any time of the year. Sowing C22 cultivar at Cavinti in
Group I and III months would make it prone to panicle and
leaf blast, respectively. At the IRRI blast nursery, leaf
and panicle infections on IR50 would be probable only in
Group I and II months. This trend was also observed for C22
at Sitiung, although some months in Group III at this site
had moderate to high degree of proneness to leaf blast. / Graduation date: 1994
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Genetic and cytological characterization of the rice blast fungus, Pyricularia oryzae CavaraLeung, Hei. January 1984 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.
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Identification and characterization of genes involved in the interaction between rice and rice blast fungus, Magnaporthe griseaJantasuriyarat, Chatchawan, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 91-101).
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Identification of Pseudomonas aeruginosa mutants unable to convert ricinoleic acid into 7,10,12-Trihydroxy-8(E)-Octadecenoic acid (TOD) and a survey of the biological activity of TODHatchett, Taylor Boozer, Lawrence, Katheryn Kay Scott, January 2009 (has links)
Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 62-71).
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Identification of genes involved in the production of a novel antifungal agent (7, 10, 12-trihydroxy-8(E)-octadecenoic acid) in Pseudomonas aeruginosaCofield, Jessica, Suh, Sang-Jin, January 2009 (has links)
Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 78-88).
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Functional Study of Pi9- and Piz-t-Associated Proteins (PANs and PAZs) in Resistance to Magnaporthe oryzaeSuttiviriya, Pavinee 08 October 2018 (has links)
No description available.
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Genetic dissection of resistance of two rice cultivars against blast fungus Magnaporthe oryzae / イネ2系統が保有するいもち病抵抗性の遺伝学的解析BASAVARAJ 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(農学) / 甲第24680号 / 農博第2563号 / 新制||農||1100(附属図書館) / 学位論文||R5||N5461(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 寺内 良平, 教授 髙野 義孝, 教授 吉田 健太郎 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
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The Role of Ubiquitination in the Interaction between Rice and Magnaporthe OryzaePark, Chan Ho 19 December 2011 (has links)
No description available.
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