Identification of the causal gene of a rice grain mutant, srs1

Abstract

To understand the molecular mechanisms forming the seed size of rice, we are carrying out the identification of causal genes in small and round mutants. We report the identification of the causal gene of a new small and round mutant, srs1 in rice. A map based cloning method was used in the study. First, a mutation site of srs1-1 was suggested to be present in the cDNA (AK120310) sequences located on the long arm of chromosome7. Then, we introduced SRS1 gene covered the cDNA into srs1-1 by Agrobacterium tumefaciens-mediated transformation method. Transformants showed wild type phenotypes. SRS1 gene has ten exons and full length cDNA is encoding 1366 amino acid. Conserved protein domains are not found in SRS1 protein. We also isolated other alleles of srs1, such as srs1-2, srs1-3, srs1-4, and srs1-5 on the basis of the information of the cDNA sequences.