水稻粉质突变体OsPDIL1-1的基因定位和候选基因分析

Starch accretion determines final grain weight and thereby it contributes greatly to grain productivity. The enzymatic process model required for starch synthesis has been established by a series of mutants using maize and rice as a model organism. However studies on some new opaque endosperm mutants showed that these new genes can not be added into the old model which has been established, so we need construct a bigger or a cross model using these novel mutants. To genetically map the mutation we developed an F2 population derived from a cross between T3612 which is an indica variety, and japonica variety NJ11. Furthermore, we used 1242 floury segregants to locate within a 61 kb region of BAC OSJNBa0058P12 which located on chromosome 11. RiceGAAS (http://ricegaas.dna.affrc.go.jp/) predicted eleven ORFs in this map region. The mutation gene was Protein Disulfide Isomerase Like 1-1 (PDIL1-1). DNA-PCR amplification and sequencing revealed a 4142bp deletion started from 123bp in PDIL1-1 CDS. Scanning electron microscopic examination revealed that the mutant T3612 endosperms contained round loosely packed starch granules. Starch synthesis activity detected Pho1 and PUL activity decreased significantly, while the SSⅠactivity increased significantly. So we conclude that the deletion of PDIL1-1 had some effects on the expression of starch synthesis-related genes and the activities of starch synthesis enzymes, and especially on the activities of Pho1, PUL and SSI, which may be the main reason led to floury endosperm.