The Light Leaf Traits In Rice Gene Gll Fine Mapping And Candidate Gene Analysis

Glabrous rice is a kind of rice that is hairless on the surface of its leaves and grains. It is the main grown cultivar in the southern region of the United States and in many African countries. Previous studies have proved that the glabrous trait is controlled by the recessive gene gl1 on chromosome 5. This study aimed to fine map and to identify candidate genes for the eventual cloning of gl1 and for further analysis of trichome morphogenesis and regulation. One segregating population was established by crossing a glabrous tropic japonica rice cultivar (AP9) and non-glabrous indica cultivar (Zhehui 7954). Microsatellite (SSR) markers around the region of RFLP markers that were previously identified to be linked with gl1 were identified and used for linkage analysis of the AP9 X Zhehui 7952 population; which proved that gl1 is linked to SSR marker RM17990. Further analysis using more SSR markers and insertion/deletion (InDel) markers mapped gl1 to the region between RM17759 and RM19831 (physically 538kb--1.649 Mb). To further delimit gl1, capillary electrophoresis and tetra-primer amplification refractory mutation system PCR markers (referred as ASPCR markers hereafter) were used for SNP analysis and bracketed gl1 to 770.5-977.1kb. This region is further narrowed down to a 6.1kb segment between 971-977.1kb by the combining mapping results of this experiment and a newly published mapping report. All four annotated genes within the 6.1 kb fragment were sequenced and sequence alignment indicated there is only one SNP between glabrous rice and pubescent rice; this SNP is located in the 5'-end untranslated region of Loc_Os05g02750, hence Loc_Os05g02750 is very likely to be the gene controlling glabrous traits in rice.