Waxy gene

The main ingredient in Thai sticky rice is rice carrying a mutation in the Waxy gene. Ingredients... 

Sano, Y. (1984). Differential regulation of waxy gene expression in rice endosperm. Theoretical and Applied Genetics 68 467. 

It is widely accepted that GBSS activity is a function of the protein coded by the waxy gene. The waxy locus gene product is a protein of molecular weight 58 KDa that is associated with starch granules and is similar to that found for the solubilized maize endosperm GBSSI.173 This protein has been extracted by heating the starch with a solution of SDS or by incubation at 37°C with 9M urea, but starch synthase activity... 

The complete deduced amino-acid sequences of the open reading frames of the Waxy genes from maize and barley are known. About 75% identity can be seen in the sequence with respect to amino acids. If functionally similar amino acids are considered, then the homology is about 81%. Thus, these two proteins are similar in sequence and probably carry out the same function in the starch granule. There is, however, very little sequence homology with the bacterial glycogen synthase beyond the N-terminal sequence. 

Shure M, Wessler S, Eederoff N. Molecular identification and isolation of the Waxy locus in maize. Cell 1983 35 225-233. Sano Y. Differential regulation of waxy gene expression in rice endosperm. Theor. Appl. Genetics 1984 68 467-473. 

One of these spontaneous mutants gave rise to the precious sticky rice of Thailand. The sticky rice lacks the starch amylose, which constitutes up to 30% of the total starch in nonsticky rice endosperm. The lack of amylose is due to a mutation in a gene called Waxy, which encodes an enzyme required for amylose synthesis (Sano 1984). Sticky rice is an important culinary and cultural component throughout East Asia and is used in festival foods and desserts. In upland regions of Southeast Asia, it is a staple food in many homes. Ten percent of the rice traded each year is sticky rice. 

Waxy A gene that encodes an enzyme for amylose synthesis. 

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