Genetic variation and gene regulation at the wx locus of rice [Oryza sativa].
1994
Hirano H.
The wx locus in rice has some advantages for genetic research and many knowledges and genetic materials have accumulated. In addition, this locus controls amylose synthesis, whose contents (relative to total starch) are quite important for a rice quality when cooked. We have cloned the gene at the wx locus and have been studying its gene regulation. The main results obtained so far are as follows: 1) The wx locus had two wild type alleles. Wx-a and Wx-b, which are distinguished by the quantitative capacities to produce Wx protein. This quantitative differences where regulated at the transcriptional level. 2) The du loci, whose mutation reduced the accumulation of amylose in the endosperm, may have the function that positively regulate the gene expression at the wx locus. 3) The levels of the Wx gene expression were activated at a cool temperature (18 degrees C), causing high amylose content in mature seeds and lowering rice quality. The results obtained here indicated that the amylose level accumulated in mature seeds strongly depended on the amount of Wx protein, suggesting that we could regulate the amylose contents at will by controlling the expression levels of the Wx gene in developing seeds of transgenic rice.
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