Genome-wide identification of glucosinolate synthesis genes in Brassica rapa.
Glucosinolates play important roles in plant defense against herbivores and microbes, as well as in human nutrition. Some glucosinolate-derived isothiocyanate and nitrile compounds have been clinically proven for their anticarcinogenic activity. To better understand glucosinolate biosynthesis in Brassica rapa, we conducted a comparative genomics study with Arabidopsis thaliana and identified total 56 putative biosynthetic and regulator genes. This established a high colinearity in the glucosinolate biosynthesis pathway between Arabidopsis and B. rapa. Glucosinolate genes in B. rapa share 72-94% nucleotide sequence identity with the Arabidopsis orthologs and exist in different copy numbers. The exon/intron split pattern of B. rapa is almost identical to that of Arabidopsis, although inversion, insertion, deletion and intron size variations commonly occur. Four genes appear to be nonfunctional as a result of the presence of a frame shift mutation and retrotransposon insertion. At least 12 paralogs of desulfoglucosinolate sulfotransferase were found in B. rapa, whereas only three were found in Arabidopsis. The expression of those paralogs was not tissue-specific but varied greatly depending on B. rapa tissue types. Expression was also developmentally regulated in some paralogs but not in other paralogs. Most of the regulator genes are present as triple copies. Accordingly, glucosinolate synthesis and regulation in B. rapa appears to be more complex than that of Arabidopsis. With the isolation and further characterization of the endogenous genes, health-beneficial vegetables or desirable animal feed crops could be developed by metabolically engineering the glucosinolate pathway.
Zang
Yun-Xiang
YX
Genomics Division, Department of Agricultural Bio-resources, National Academy of Agricultural Science, Rural Development Administration, Suwon, Korea.
Kim
Hyun Uk
HU
Kim
Jin A
JA
Lim
Myung-Ho
MH
Jin
Mina
M
Lee
Sang Choon
SC
Kwon
Soo-Jin
SJ
Lee
Soo-In
SI
Hong
Joon Ki
JK
Park
Tae-Ho
TH
Mun
Jeong-Hwan
JH
Seol
Young-Joo
YJ
Hong
Seung-Beom
SB
Park
Beom-Seok
BS
D000818:Animals; D017360:Arabidopsis / Q000235:genetics; D005075:Biological Evolution; D029741:Brassica rapa / Q000235:genetics / Q000378:metabolism; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D018745:Genome, Plant; D005961:Glucosinolates / Q000096:biosynthesis*; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D015238:Sulfotransferases / Q000145:classification / Q000235:genetics* / Q000378:metabolism
D005961:Glucosinolates; D010940:Plant Proteins; D015238:Sulfotransferases