Variation in Key Flavonoid Biosynthetic Enzymes and Phytochemicals in 'Rio Red' Grapefruit (Citrus paradisi Macf.) during Fruit Development.

In the current study, the phytochemical contents and expression of genes involved in flavonoid biosynthesis in Rio Red grapefruit were studied at different developmental and maturity stages for the first time. Grapefruit were harvested in June, August, November, January, and April and analyzed for the levels of carotenoids, vitamin C, limonoids, flavonoids, and furocoumarins by HPLC. In addition, genes encoding for phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), and 1,2-rhamnosyltransferase (2RT) were isolated, and their expression in grapefruit juice vesicles was studied.

Identification of a novel chimeric gene, orf725, and its use in development of a molecular marker for distinguishing among three cytoplasm types in onion (Allium cepa L.).

A novel chimeric gene with a 5' end containing the nearly complete sequence of the coxI gene and a 3' end showing homology with chive orfA501 was isolated by genome walking from two cytoplasm types: CMS-S and CMS-T, both of which induce male-sterility in onion (Allium cepa L.). In addition, the normal active and variant inactive coxI genes were also isolated from onions containing the normal and CMS-S cytoplasms, respectively.

Marker-assisted genotype analysis of bulb colors in segregating populations of onions (Allium cepa).

Bulb color in onions (Allium cepa) is an important trait whose complex inheritance mechanism involves epistatic interactions among major color-related loci. Recent studies revealed that inactivation of dihydroflavonol 4-reductase (DFR) in the anthocyanin synthesis pathway was responsible for the color differences between yellow and red onions, and two recessive alleles of the anthocyanidin synthase (ANS) gene were responsible for a pink bulb color. Based on mutations in the recessive alleles of these two genes, PCR-based markers for allelic selection were developed.