Mutated ALS genes

In addition to being useful in the field, the herbicide resistance phenotype conferred by mutated ALS genes is a useful selectable marker in the laboratory. 

Use of the Mutated ALS Genes for Resistance Management of ALS-inhibiting Herbicides... 

It was expected that novel mutated ALS genes that had different mutations from those reported in papers and patents were obtained through the selection of... 

First, the callus from rice seeds was induced. The calli were then cultured with 1 micromolar of BS for about 2 months so that the BS-resistant cells were generated. The cells were next cultured with higher concentrations of BS. And finally, several kinds of spontaneous BS-resistant ceils that could grow under the pressure of 100 micromolar of BS were obtained. A wild-type ALS gepe and a mutated ALS gene have been cloned from the BS-resistant cells using the partial cDNA that is an expressed sequence tag obtained from the MAFF DNA bank of Japan as a homologous hybridization probe. Fig. 9 shows a comparison of the deduced amino acid sequences between the wild-type ALS and the mutated ALS. 

The first amino acid shows the sequences between position 361 and the C-terminal position 644 in the mutated ALS, and second amino acid sequence does that in the wild-type ALS. The mutations involved the residues of tryptophan 548 to leucine and serine 627 to isoleucine. This double mutation on rice is a new combination of spontaneous mutations with the novel substitution at the serine position (7). One-point mutated ALS genes were then prepared to compare the sensitivities of their recombinant ALS s to the ALS-inhibiting herbicides with that of the two-point mutant (Fig. 10). 

On the conttary, the ALS expressed from the two-point mutated ALS gene showed quite different sensitivities to the herbicides. This ALS showed a... 

Use of the mutated ALS genes for the genetic transformation and the herbicide resistance management... 

Fig. 16. Use of rice mutated ALS genes as markers for gene technologies...

Using the accumulated knowledge concerning rice ALS genes, rice mutated ALS genes were artificially prepared. (Fig. 17). 

These mutated ALS genes except for the W548L/SS27I double mutant were prepared by PCR and SPR using mutations detected in BS-resistance rice ceils, or site-directed mutagenesis. 

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