* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Slide 1
Epigenetics of neurodegenerative diseases wikipedia , lookup
Pathogenomics wikipedia , lookup
Genetic engineering wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Gene nomenclature wikipedia , lookup
Gene desert wikipedia , lookup
Essential gene wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Public health genomics wikipedia , lookup
Genomic imprinting wikipedia , lookup
Ridge (biology) wikipedia , lookup
Genetically modified organism containment and escape wikipedia , lookup
Genetically modified crops wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Genome evolution wikipedia , lookup
History of genetic engineering wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Gene expression programming wikipedia , lookup
Minimal genome wikipedia , lookup
Genome (book) wikipedia , lookup
Microevolution wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
A. Functional genomics on seed development Crop seeds contribute major calories and nutrition to human. To increase the yield and nutrition, understanding the mechanism of seed formation is essential. Seed development involves embryogenesis and endosperm development, a complex and orchestrated process that involves many gene functions and is vital to reproduction of plants. We are interested in 1) functional analysis of the genes that regulate seed development; 2) elucidation of carotenoid catabolism mechanism in seeds. 1. Genetic and functional dissection of genes regulating maize seed development. Using maize as a model system, we have A B C isolated small kernel (smk) and embryo defective mutants (emb) by using the Robertson’s Mutators as mutagens. Recently we have cloned several genes that are important to embryogenesis. Loss emb12 emb12 WT Emb12b of function in these genes causes embryo Emb12c Transposon insertion sites Emb12a development arrested at transition stage Emb12 (Fig. 1). Using approaches of biochemistry, genetics and molecular Fig. 1. Arrested embryo development in emb12. mutant and the emb12 gene structure. biology, we are attempting to decipher their functions. 2. Provitamin A nutrition accumulation in crop seeds Carotenoids are the precursors of Vitamin A, a nutrient essential to the development of immune system and eye particularly in children. Vitamin A deficiency is a major problem in developing countries. One way to combat this problem is to create crop grains with fortified carotenoid contents. As manifested in the Golden Rice (Paine et al., 2005; Ye et al., 2000), introducing carotenoid synthetic genes increases carotenoid accumulation. Our work on White cap demonstrated that carotenoid catabolism (degradation) also plays an important role in carotenoid accumulation in seeds. White cap locus is a dominant mutant conferring carotenoid deficient phenotype (Fig. 2a). Molecular cloning demonstrated that Wc contains a tandem array of a gene encoding carotenoid cleavage dioxygenase 1 (CCD1). CCD1 is capable to degrade a broad spectrum of carotenoids (fig. 2b). From analyses of CCD genes in other species, it appears that this degradation pathway is conserved in plants. This opens the possibility to modify the Golden Rice to accumulate more provitamin A. In addition, we also attempt to elucidate the biological function of CCD1 gene and the mechanism of the tandem array creation. A B ZmCCD1 - + Zeaxanthin C - + - β-carotene + Lycopene ZmCCD1 activity in E. coli cells β-carotene O O + O Dominant Wc (b-ionone) C14 dialdehyde O + (b-ionone) Fig. 2. Wc encodes a ZmCCD1 protein involved in the degradation of carotenoids in maize seeds. B. Regulation of abscisic acid biosynthesis To establish the abscisic acid (ABA) biosynthesis pathway in plant, we cloned and analysed the function of VP14, which is a key gene in ABA biosynthesis pathway.