Identification Of A Mutant With Drooping Leaf And Homeotic Floral Organ In Rice(Oryza Sativa L.)

Rice is one of the most important food crops in the world. Rice production and quality depend on the development of the floral organ. Rice is also a model plant for study of the molecular developmental biology in monocots. The identity of floral organs depends on the expression of genes in specific domains of the floral meristem. The homeotic genes were studied the most. Now over 70 homeotic genes were isolated from rice by using the conserved sequences of the homeotic genes of dicots as probe screening the rice genomic library or cDNA. The study of the function and expression of genes using mutants is a trend in functional genomics.We discovered one mutant(c//r) from indica rice maintainer line D62B. In this study we have investigated the anatomical structure of floral organs, genetic analysis of mutant traits and molecular tagging of gene. The main results are summarized as follows:1. Plant phenotype and floral anatomical structure of dlr mutant The mutant plant shows drooping leaf and glumaceous lodicules and morphological transformation of pistils into stamens. A mutant floret consists of 7 to 8 stamens.2. Genetic analysis of dlr mutant Three F2 populations from dlr mutant crossed with three various rice varieties, Minghui63, R362, Zhonghua99-6586, respectively. Results of genetic analysis indicated that the traits of dlr mutant are controlled by a single recessive gene.3. Molecular tagging of gene of dlr mutant The F2 population, derived from R362/dlr, was used to screen molecular markers linked with dlr, subsequently, the gene was mapped near to RM282 on chromosome 3, with distances of 5.56cM.