Genetic Analysis of a Leaf Angle Mutant in Rice

Abstract

The leaf angle defined as the degree between leaf blade and stem is an important factor of crop yield. The most crucial part of leaf angle regulation in rice is a collar (lamina joint). If adaxial side of the collar is elongated, the leaf would be reversely rolled, otherwise, the plant would be erect type. To figure out leaf angle regulation related genes and their mode of action, we identified a rice large leaf angle mutant obtained by EMS (ethyl methane sulfonate) treatment to Ilpumbyeo, ilpum large leaf angle (illa), which results from elongated cell length of adaxial side at the lamina joint. The phenotypic characterization of illa mutant and genetic mapping were performed. Additionally, we carried out leaf inclination test to elucidate between Brassinosteroid (BR) and leaf angle regulation of illa. Map based cloning using 30 STS (Sequence-Tagged Sites) and 57 SS-STS (Sub-species Specific Sequence-Tagged Site) markers showed that the illa gene seems to be located on the short arm of chromosome 11. Each whole genome of Ilpumbyeo, illa mutant, and bulked F2 plants showing mutant phenotype was sequenced using NGS method to find exact mutation point. After all SNPs and indels were called, the candidate gene was considered to be located on chromosome 1, 10 or 11. Further identification of each candidate genes is progressing.