| Budget Amount *help |
¥15,800,000 (Direct Cost: ¥15,800,000)
Fiscal Year 2006: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2005: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2004: ¥10,500,000 (Direct Cost: ¥10,500,000)
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| Research Abstract |
1) Construction of cDNA ibrary and EST analysis of Colletotrichum higginsianum
In this research, cDNA library of Colletotrichum higginsianum consisting of 1,700 genes prepared from pre germinated conidia, germinating conidia, appressorium, and infection hyphae. Among them 1,110 genes were unique and characterized by gene ontology (GO) annotations. The library genes were characterized as gene expression(20%), cellular differentiation (21%), metabolisms (20%), unknown function (39%).
2) Responses to environment and appressorium differentiation
In this research, it became evident that a plant leaf surface substance(s) induces germination of Colletotrichum lagenarium on host plant and this induction was seems to be mediated by cAMP dependent protein kinase signal transduction pathway. A MAP kinase gene was cloned and function of this gene was analyzed by gene disruption experiment. From this, it became evident that a MAP kinase pathway is involved in germination, appressorium formation and in
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vasive growth in host plant. Furthermore, a transcription factor that involved in expression of melanin biosynthesis genes was isolated and characterized. This transcription factor positively regulated two structural melanin biosynthesis genes in a development dependent manner. Also this transcription factor showed very unique structure that contains two different type of DNA binding motifs. This was a first finding of transcription factor among eukaryotic organism.
3) Construction of EST library and analysis of expression profiles of Brassica rapa during fungal pathogen Colletotrichum higginsianum infection
To perform comparative sequence and transcriptome analyses between Brassica rapa and Arabidopsis thaliana, B. rapa cDNA microarray was prepared using 1,820 (ca. 2 K) cDNA clones selected from 2,166 non-redundant sequences of cDNA library of Chinese cabbage. The gene expression during infection with fungal pathogen Colletotrichum higginsianum and treatments with signaling molecules was analyzed using 2 K B. rapa and 1.2 K Arabidopsis cDNA microarrays. In B. rapa, the results suggested a large correlation coefficient between compatible pathogen C higginsianum-infection and the treatment with salicylic acid, methyl jasmonate, or ethephon. The expression profiles of 145 counterpart gene sets between the B. rapa and Arabidopsis were distributed in the self-organizing map analysis. The 28 % of them indicated similarities in the two species transcriptome. These expressed sequence tag (EST) and microarray data should provide a valuable resource for functional genomics on the crops Less
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