Fine Mapping Of Two Hooked-Glume Related Genes, SH1and SH2, From Two Rice Varieties

Rice (Oryza sativa L.) is one of the most fascinating model species in which to investigate flower development because it has a unique structure of the inflorescence and flower that has greatly diverged from those of model eudicots (e.g. Arabidopsis thaliana, Antirrhinum majus, and Petunia). The spikelet is the primary unit of the rice inflorescence, it consists of a pair of bract-like organs (lemma and palea), two lodicules, six stamens and one pistil. The lemma and palea are grass-specific perianth organs, but their identities are still controversial. And the shape and size of glumes determines the shape and size of rice, is closely related to the production of rice. Clarifying development mechanism of rice lemma and palea can provide the theoretical basis and practical guidance for production. In this article, two recombinant inbred lines (RIL) from9311and PA64S, BC37and BC94, as well as a tropical japonica rice variety were used. Morphological observation, genetic analysis, gene mapping and preliminary functional analysis were carried out in this research. The main results were as follows:-Paraffin section of the cross-section of the glume showed that glume cell morphology and composition is no different from NPB, and the occlusion of lemma and palea is normal. But in BC37and BC94, in addition to malformed glume, other floret organs, especially stamen number, were abnormal, too.-F1of BC37and BC94still display a hooked glume phenotype, while both F1of BC37and SHI, F1of BC94and SHI glumes were normal, indicating that hooked glume in BC37and that in BC94were resulted by a same gene, named SH2, while the hooked glume in SH1was controlled by another gene, SH1, which was non-allelic to SH2.-Population for mapping was constructed by crosses between9311and SH1, NPB and BC37. Fine mapping indicated that SH1localized over a 92kb region between RM3740and RM3148on the short arm of chromosome1, while SH2localized over a103kb region between STS3-8and STS3-9on the short arm of chromosome3.-Near isogenic line of SH2was constructed by continuous backcross with9311. The morphology of SH2-NIL was truly similar to9311, except grain shape. The grain length of SH2-NIL is similar to9311, and grain width was smaller than9311. More obviously, glumes of SH2-NIL were hooked.