Abstract
Gibberellins (GAs) have many biological roles in higher plants. We performed genetic analysis on rice GA-related mutants, including GA-deficient and -insensitive mutants. The analysis revealed that rice GA-deficient mutations are not transmitted as Mendelian traits to the next generation following the self-pollination of F1 heterozygous plants, although GA-insensitive mutations are transmitted normally. In order to understand these differences in transmission in GA-deficient and GA-insensitive mutants, we examined the effect of GA on microsporogenesis and pollen-tube elongation in rice using new GA-deficient and -insensitive mutants that produce semi-fertile flowers. Phenotypic analysis revealed that the GA-deficient mutant, rpe1, is defective in pollen-tube elongation, resulting in a low fertilization frequency, whereas the GA-insensitive semi-dominant mutant Slr1-d3 is mainly defective in viable pollen production. We also examined the quantitative RT-PCR analysis of GA-biosynthesis and signal-related genes. Based on the observations, we will discuss the ways of transmissions of these GA-related mutations.
