• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.221-228
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• 1987

The optimum temperature range for conidial germination of Pyriculacia oryzae on a slide glass was $26{\sim}30^{\circ}C$, at which at least four hours of leaf wetness period was required to germinate. Conidial germination was significantly reduced under dry conditions (relative humidity<85%) at $34^{\circ}C$ but not at lower temperature (18, 22, 26, $30^{\circ}C$). Number of lesions developed were greater at $26^{\circ}C$ than at other temperature tested. The average leaf wetness period required for production of a lesion per plant was 22 hours at $18^{\circ}C$, 16 hours at $22^{\circ}C$, 10 hours at $26^{\circ}C$, and 8 hours at $30^{\circ}C$. Less than one lesion per plant occurred at $34^{\circ}C$ even under 24 hours of leaf wetness period. The time period between inoculation and lesion appearance was $7{\sim}8$ days at $18^{\circ}C$, $4{\sim}5$ days at $22^{\circ}C$ and $26^{\circ}C$, and $3{\sim}4$ days at $30^{\circ}C$. The time period required for lesion appearance after inoculation was not affected by leaf wetness period and relative humidity. Lesion length increased most rapidly at $30^{\circ}C$ during the first four days after lesion appearance. Thereater, the rate of increase in lesion length was geratest at $26^{\circ}C$. The average increment of lesion length per day when relative humidity was greater than 90% was 0.7mm at $18^{\circ}C\;and\;22^{\circ}C$, 1mm at $26^{\circ}C$, and 0.8mm at $30^{\circ}C$. When relative humidity was less than 85%, the increments of lesion length per day were approximately $50{\sim}60%$ of those under humid conditions (relative humidity>90%) at all temperature regimes except $30^{\circ}C$. Relative humidity did not significantly affected lesion length at $30^{\circ}C$.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.9-9
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• 2014

Null mutants generated by targeted gene replacement are frequently used to reveal function of the genes in fungi. However, targeted gene deletions may be difficult to obtain or it may not be applicable, such as in the case of redundant or lethal genes. Constitutive expression system could be an alternative to avoid these difficulties and to provide new platform in fungal functional genomics research. Here we developed a novel platform for functional analysis genes in Magnaporthe oryzae by constitutive expression under a strong promoter. Employing a binary vector (pGOF1), carrying $EF1{\beta}$ promoter, we generated a total of 4,432 transformants by Agrobacterium tumefaciens-mediated transformation. We have analyzed a subset of 54 transformants that have the vector inserted in the promoter region of individual genes, at distances ranging from 44 to 1,479 bp. These transformants showed increased transcript levels of the genes that are found immediately adjacent to the vector, compared to those of wild type. Ten transformants showed higher levels of expression relative to the wild type not only in mycelial stage but also during infection-related development. Two transformants that T-DNA was inserted in the promotor regions of putative lethal genes, MoRPT4 and MoDBP5, showed decreased conidiation and pathogenicity, respectively. We also characterized two transformants that T-DNA was inserted in functionally redundant genes encoding alpha-glucosidase and alpha-mannosidase. These transformants also showed decreased mycelial growth and pathogenicity, implying successful application of this platform in functional analysis of the genes. Our data also demonstrated that comparative phenotypic analysis under over-expression and suppression of gene expression could prove a highly efficient system for functional analysis of the genes. Our over-expressed transformants library would be a valuable resource for functional characterization of the redundant or lethal genes in M. oryzae and this system may be applicable in other fungi.