Genetic Analysis And Gene Mapping Of Rolled Leaf Mutants In Rice

Rice (Oryza sativa L.) is one of the most important cereal crops in the world. As the increasing demands for food and continuing declines of the cultivated lands, it is urgent to enhance its production. Rolled leaf as one of the important morphological indicators in the super rice breeding, have been sufficiently validated in production and practices. Leaves as the main photosynthetic organs of rice, moderate rolling could help to keep the blades upright, improve the transmittance environment to reduce the extinction coefficient, establish a good platform for the group to accept the light energy as much as possible, thereby enhancing photosynthesis and light utilization efficiency. Therefore, to elucidate the molecular mechanism of rice rolled leaf, not only contribute to the understanding of leaf developmental mechanisms, but also help us to promote crop’s output and quality through improved its genetic character.There are plenty of rolled leaf resources with genetic stability in rice, Cloning and identification of these rice genes are the basis for improving varieties. In present study, three rolled leaf mutants, designated as rolled leaf3(t)-1, rolled leaf3ω-2and rolled leaf9ω were derived from the indica cultivar9311, radiated by60Co-y ray. We carried out a comprehensive study including morphological, agronomical, cytological, genetic properties and gene mapping in this study. The results are as following:Part1:The rl3(t) mutant1. Compared with wide type (WT)9311, many agronomic traits of rl3(t) are changed, such as leaves of rl3(t) are significantly rolled, plant height turns lower, panicle length shorter, flag leaf length and width were changed obviously, and the seed setting percentage decreased.2. Genetic analysis indicates that the rl3(t) mutant isolated from9311mutant library was a new rolled leaf mutant, suggesting the phenotype of rolled leaf mutant was controlled by a recessive gene. rl3(t) is a rolled leaf gene has not yet been reported. 3. Crossing between the two mutant, the phenotype of F1(rl3(t)-l/rl3(t)-2) plants were rolled leaf, suggesting they are alleles.4. Initial mapping of the mutant gene shows that rl3(t) was located between the STS markers M3-45and SSR markers RM6676on the long arm of chromosome3, with genetic distance5.5cM and4.4cM, respectively; Then, using more individuals, the gene was fine mapping to a120kb region nearby14.1Mb, Where18predicted genes were found in this region, of which11are functional genes.Part2:The rl9(t) mutant1. Compared with wide type, many agronomic traits ofrl9(t) are changed, such as leaves of rl9(t) are obviously rolled, plant height turns lower, flag leaf length and width were changed obviously and accompanied with the phenomenon of glume split. The seed setting rate was significantly reduced.2. The phenotype of rolled leaf mutant rl9(t) was controlled by a recessive gene, which was located between the SSR markers RM3912and RM6839on the long arm of chromosome9, with genetic distance12.2cM and4.9cM, respectively.3. The gene was located between STS markers M9-50and M9-53, there are about89kb on BAC clone AP005904.