Articles
GENOME ORGANIZATION OF GENE ENCODING LACHRYMATORY FACTOR SYNTHASE IN ALLIUM CEPA
Article number
969_6
Pages
73 – 80
Language
English
Abstract
Most people experience the lachrymatory smell that is emitted when a bulb of onion (Allium cepa) is cut with a knife in a kitchen.
The lachrymatory factor (LF), identified as propanthial-S-oxide more than 40 years ago, is produced during the enzymatic conversion of 1-propenyl sulfenic acid, a putative reaction product of alliinase acting on trans-1-propenyl cysteine sulfoxide (trans-PRENCSO) by lachrymatory factor synthase (LFS). As LF is pungent to humans, a low-LF-producing onion would be sweet; moreover, the suppression of LF production would cause an increase in thiosulfinates, which may be a precursor of health beneficial sulfur compounds in onion.
Therefore, LFS is an important target gene in onion breeding for both flavor intensity and healthfulness.
To obtain basic and valuable information regarding low-LFS onion breeding, we examined the chromosomal organization of the LFS gene in A. cepa. In the first level of analysis, the chromosomal assignment of the LFS gene to chromosome 5 of A. cepa was completed via the use of a complete set of A. fistulosum-shallot monosomic addition lines (FF+1A-FF+8A). The subsequent use of an F2 mapping population from the interspecific cross A. cepa × A. roylei also permitted the assignment of the LFS gene locus to this chromosome.
Furthermore, a BAC-FISH study using two BAC clones bearing LFS genes as a probe showed that LFS genes are localized in the proximal region of the long arm of the chromosome.
We hope that these results lead to the marker-assisted selection of a low-LFS onion population.
The lachrymatory factor (LF), identified as propanthial-S-oxide more than 40 years ago, is produced during the enzymatic conversion of 1-propenyl sulfenic acid, a putative reaction product of alliinase acting on trans-1-propenyl cysteine sulfoxide (trans-PRENCSO) by lachrymatory factor synthase (LFS). As LF is pungent to humans, a low-LF-producing onion would be sweet; moreover, the suppression of LF production would cause an increase in thiosulfinates, which may be a precursor of health beneficial sulfur compounds in onion.
Therefore, LFS is an important target gene in onion breeding for both flavor intensity and healthfulness.
To obtain basic and valuable information regarding low-LFS onion breeding, we examined the chromosomal organization of the LFS gene in A. cepa. In the first level of analysis, the chromosomal assignment of the LFS gene to chromosome 5 of A. cepa was completed via the use of a complete set of A. fistulosum-shallot monosomic addition lines (FF+1A-FF+8A). The subsequent use of an F2 mapping population from the interspecific cross A. cepa × A. roylei also permitted the assignment of the LFS gene locus to this chromosome.
Furthermore, a BAC-FISH study using two BAC clones bearing LFS genes as a probe showed that LFS genes are localized in the proximal region of the long arm of the chromosome.
We hope that these results lead to the marker-assisted selection of a low-LFS onion population.
Publication
Authors
N. Masamura, J. McCallum, F. Kenel, M. Pither-Joyce, L. Khrustaleva, G. Suzuki, Y. Mukai, N. Yamauchi, M. Shigyo
Keywords
alien monosomic addition lines, genetic mapping, BAC-FISH, trans-1-propenyl cysteine sulfoxide (trans-PRENCSO), sulfur compound
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