Development Of Genic Markers For Special Nutritional Quality In Rice

With the improvement of living standards and the awareness of health care,there is an increasing demand of human beings for special nutrients in crops.The special nutrients in rice grains refer to a kind of nutrients accumulated benefits to comsumers,including vitamins,oils,active polysaccharides,free radical scavengers,flavonoids,steroids,essential trace elements,gamma-aminobutyric acid(GABA),mineral elements,chlorogenic acid compounds,essential amino acids specific gluten,dietary fiber and the specific content of starch and other metabolites.The production and accumulation of these special nutrients are regulated by multi-genes in various metabolic pathways.In the present study,we first selected a number of candidate genes that affect the special nutrients in rice by analyzing metabolomics data and genome-wid-association analysis data.Then,we identified some informative sequence polymorphisms at these genes to design corresponding genic markers,and validated their usefulness and functions by using chromosome segment substitution lines and a mini-core germplasm collection.Finally,we used the developed genic markers to improve several special nutritional qualities of a rice variety through marker-assisted breeding.The main results are as follows:1.A total of 52 candidate genes associated with relevant specific nutrients were selected by analysis of the rice metabolome and genome-wide association data.The corresponding molecular markers of these genes were designed.Among them,41 genic markers have been successfully developed for several specific nutrients.2.A set of genice markers were developed for the key genes in rice anthocyanin and procyanidins metabolic pathways,including Ra,Rc,Rd and other flavonoid biosynthesis genes.It can be used for studing of the genetic bases of flavonoid biosynthesis in rice,and for molecular assisted selection of grain color traits as well.3.Using an F2 segregating population from a cross between ZS97 B and NQ58,the latter is a chromosome segment substitution line that carries a target NIP chromosomal segment in the genetic background of ZS97 B,we found that one gene LOC_Os11g01340 controlls the ratio of linoleic acid and ?-linolenic acid(LA: ALA) in seed embryo of rice.Accordingly,we developed a genic marker OSFA-5 for that gene.4.The marker OSFA-5 could effectively distinguish two haplotypes in the rice mini-core germplasm collection,which showed a significant difference in the contents of linoleic acid and linolenic acid,and its ratio in the seed embryo.5.Based on the developed genic markers,we carried out a molecular-assisted breeding scheme to improve several special nutrient quality including fatty acid,sterol content,anthocyanin and fragrance in rice variety 2-33.After comprehensive evaluation the special nutrients by genic markers,we have obtained 20 lines with an improved promising grain quality.