Origin of Seed Shattering in Rice

A simple change in a single gene can cause a dramatic phenotype change during rice domestication, the group of researchers in China and Singapore said in their paper published in the journal Planta.  The researchers isolated and characterized a single dominant gene called Shattering1 (SHA1), which is responsible for controlling seed shattering. They have determined that a single nucleotide change in SHA1 is correlated with the seed shattering character in rice.

During rice domestication, the seed shattering characteristic was eliminated. Wild rice species disperse seeds freely at maturity, while cultivated rice retains seeds on their straws. The non-seed shattering characteristic of cultivated rice contributes to its easy harvest during production.

Previous research using genetic and molecular analyses had determined that seed shattering in rice is controlled by two dominant genes in chromosomes 1 and 4.  The isolation and characterization of SHA1 provided important information on the control of the shattering character. SHA1 encodes for a plant specific transcription factor and was determined to have a single amino acid substitution (K79N) caused by a single nucleotide change (g237t). Among the 233 rice accessions the researchers examined, g237t was only found in the cultivated indica and japonica cultivars, but not in any of the wild rice accessions.

For more information, the full paper can be accessed by subscribers at http://www.springerlink.com/content/h713487822047663/.