A dwarf mutant rice line was selected from an Ac/Ds insertion mutant population and named dwf1. The phenotype of F₁ and F₂ plants derived from a cross between dwf1 and Dongjin indicated that a single recessive gene is responsible for the mutant phenotype, and we named this gene dwf1. Resequencing of the dwf1 line and Dongjin (wild type) revealed 42,386 homozygous single nucleotide polymorphisms (SNPs) between dwf1 line and Dongjin. MutMap analysis was performed by sequencing a DNA pool prepared from 100 mutant type plants in the dwf1/Dongjin F₂ population, and it was found that the dwf1 gene was located in the 23 ~ 30 Mbp region on chromosome 4. In this region, we found a non-synonymous SNP in the Os04g0469800 gene, which was reported as D11 gene encoding a cytochrome P450 family protein involved in the biosynthesis of brassinosteroids (BRs). This SNP was regarded as the causative SNP for the dwf1 phenotype, and the dwf1 gene is a novel allele of D11. We performed mapping of the dwf1 gene with five SNP markers on chromosome 4 with 190 dwf1/Dongjin F₂ plants. The phenotype of F₂ plants was completely co-segregated with genotypes of the J10402 marker, which was developed based on the non-synonymous SNP in the D11 gene. These results will contribute to the study of the molecular biological functions of the D11 gene and BRs.

Perilla is an oilseed crop cultivated in Korea since ancient times. Due to the high α-linolenic acid content in perilla, perilla seed oil can easily become rancid. α-Linolenic acid is synthesized by two enzymes, endoplasmic reticulum-localized Δ15 desaturase (FAD3) and chloroplast-localized Δ15 desaturase (FAD7) in vivo. In order to lower the α-linolenic acid content of the seed oil without disturbing plant growth, we tried to suppress the expression of only the FAD3 gene using RNA interference, whilst maintaining the expression of the FAD7 gene. Seventeen transgenic plants with herbicide (Basta™) resistance were obtained by Agrobacterium-mediated transformation using hypocotyls of perilla plants. The transgenic plants were firstly confirmed by treatment with 0.3% (v/v) Basta™ herbicide, and the expression of FAD3 was measured by Northern blot analysis. The α-linolenic acid content was 10-20%, 30-40%, and 60% in two, seven, and three of the twelve T₁ transgenic perilla plants which had enough seeds to be analyzed for fatty acid composition, respectively. Analysis of the fatty acid composition of T₂ progeny seeds from T₁ plants with the lowest α-linolenic acid content showed that the homozygous lines had 6-10% α-linolenic acid content and the heterozygous lines had 20-26% α-linolenic acid content. It is expected that the reduction in α-linolenic acid content in perilla seed oil will prevent rancidity and can be utilized for the production of high-value functional ingredients such as high γ-linolenic acid.