Difference between revisions of "User:Xu Congli"

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(Created page with "The resistance (R) gene Pi37, present in the rice cultivar St. No. 1, was isolated by an in silico map-based cloning procedure. The equivalent genetic region in Nipponbare con...")
 
 
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The resistance (R) gene Pi37, present in the rice cultivar St. No. 1, was isolated by an in silico map-based cloning procedure. The equivalent genetic region in Nipponbare contains four nucleotide binding site–leucine-rich repeat (NBS–LRR) type loci. These four candidates for Pi37 (Pi37-1, -2, -3, and -4) were amplified separately from St. No. 1 via long-range PCR, and cloned into a binary vector. Each construct was individually transformed into the highly blast susceptible cultivar Q1063. The subsequent complementation analysis revealed Pi37-3 to be the functional gene, while -1, -2, and -4 are probably pseudogenes. Pi37 encodes a 1290 peptide NBS–LRR product, and the presence of substitutions at two sites in the NBS region (V239A and I247M) is associated with the resistance phenotype. Semiquantitative expression analysis showed that in St. No. 1, Pi37 was constitutively expressed and only slightly induced by blast infection. Transient expression experiments indicated that the Pi37 product is restricted to the cytoplasm. Pi37-3 is thought to have evolved recently from -2, which in turn was derived from an ancestral -1 sequence. Pi37-4 is likely the most recently evolved member of the cluster and probably represents a duplication of -3. The four Pi37 paralogs are more closely related to maize rp1 than to any of the currently isolated rice blast R genes Pita, Pib, Pi9, Pi2, Piz-t, and Pi36.
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The causal gene of a novel small and round seed mutant phenotype (srs3) in rice was identified by map-based cloning and named the SRS3 gene. The SRS3 gene was grouped as a member of the kinesin 13 subfamily. The SRS3 gene codes for a protein of 819 amino acids that contains a kinesin motor domain and a coiled-coil structure. Using scanning electron microscopy, we determined that the cell length of seeds in the longitudinal direction in srs3 is shorter than that in the wild type. The number of cells of seeds in the longitudinal direction in srs3 was not very different from that in the wild type. The result suggests that the small and round seed phenotype of srs3 is due to a reduction in cell length of seeds in the longitudinal direction. The SRS3 protein, which is found in the crude microsomal fraction, is highly expressed in developing organs.

Latest revision as of 01:14, 6 June 2014

The causal gene of a novel small and round seed mutant phenotype (srs3) in rice was identified by map-based cloning and named the SRS3 gene. The SRS3 gene was grouped as a member of the kinesin 13 subfamily. The SRS3 gene codes for a protein of 819 amino acids that contains a kinesin motor domain and a coiled-coil structure. Using scanning electron microscopy, we determined that the cell length of seeds in the longitudinal direction in srs3 is shorter than that in the wild type. The number of cells of seeds in the longitudinal direction in srs3 was not very different from that in the wild type. The result suggests that the small and round seed phenotype of srs3 is due to a reduction in cell length of seeds in the longitudinal direction. The SRS3 protein, which is found in the crude microsomal fraction, is highly expressed in developing organs.