Complete assignment of structural genes involved in flavonoid biosynthesis influencing bulb color to individual chromosomes of the shallot (Allium cepa L.)

Abstract

We analyzed Japanese bunching onion ( Allium fistulosum L.) -shallot ( Allium cepa L. Aggregatum group) alien chromosome addition lines in order to assign the genes involved in the flavonoid biosynthesis pathway to chromosomes of the shallot. Two complete sets of alien monosomic additions (2 n = 2 x + 1 = 17) were used for determining the chromosomal locations of several partial sequences of candidate genes, CHS, CHI, F3H, DFR, and ANS via analyses of PCR-based markers. The results of DNA marker analyses showed that the CHS-A, CHS-B, CHI, F3H, DFR, and ANS genes should be assigned to chromosomes 2A, 4A, 3A, 3A, 7A, and 4A, respectively. HPLC analyses of 14 A. fistulosum -shallot multiple alien additions (2 n = 2 x + 2 -2 x + 7 = 18 -23) were conducted to identify the anthocyanin compounds produced in the scaly leaves. A direct comparison between the genomic constitution and the anthocyanin compositions of the multiple additions revealed that a 3GT gene for glucosylation of anthocyanidin was located on 4A. Thus, we were able to assign all structural genes involved in flavonoid biosynthesis influencing bulb color to individual chromosomes of A. cepa .

Single Alien Chromosome Additions from Shallot (Allium cepa L. Aggregatum group) Increase Endogenous Polyphenol Contents in Japanese Bunching Onion

“…In the present study, the PAL gene was allocated to chromosome 2A of shallot. Masuzaki et al (2006a) revealed that the CHS-A gene was assigned to chromosome 2A of shallot. The higher polyphenol accumulation observed in the green leaf tissue of FF + 2A could have been due to the higher expression of these enzyme genes.…”

“…Previous studies also revealed that several lines with alien chromosomes which possessed the key regulatory and structural genes for flavonoid metabolism showed different flavonoid compositions in the leaf sheath tissues (Masuzaki et al, 2006a(Masuzaki et al, , 2006bShigyo et al, 1997b). …”

Molecular and biochemical identification of alien chromosome additions in shallot (Allium cepa L. Aggregatum group) carrying extra chromosome(s) of bunching onion (A. fistulosum L.)

“…Shigyo and co-workers demonstrated that chromosome manipulation techniques via the use of monosomic addition lines could be available to modify the endogenous chemical components of the bunching onion, such as flavonoids (Shigyo et al, 1997b;Masuzaki et al, 2006aMasuzaki et al, , 2006b, carbohydrates (Hang et al, 2004a;Yaguchi et al, 2008b), chlorophyll (Dissanayake et al, 2008), or vitamin C (Yaguchi et al, 2008a). In most cases, alien chromosome addition lines induced the upregulation of these functional component productions.…”

Biochemical Analyses of the Antioxidative Activity and Chemical Ingredients in Eight DifferentAlliumAlien Monosomic Addition Lines

“…In a previous study, the PAL and CHS-A genes have been assigned to chromosome 2A of shallot. 8,22) The higher polyphenol accumulation observed in FF+2A could have been due to the higher expression of these enzyme genes. Thus, anonymous genes by the gene dosage effect related to the upregulation of polyphenol production and following the increase in ORAC values, other than PAL and CHS, could be located on chromosomes 6A and 8A.…”