Genes up-regulated during red coloration in UV-B irradiated lettuce leaves.
Molecular analysis of gene expression differences between green and red lettuce leaves was performed using the SSH method. BlastX comparisons of subtractive expressed sequence tags (ESTs) indicated that 7.6% of clones encoded enzymes involved in secondary metabolism. Such clones had a particularly high abundance of flavonoid-metabolism proteins (6.5%). Following SSH, 566 clones were rescreened for differential gene expression using dot-blot hybridization. Of these, 53 were found to overexpressed during red coloration. The up-regulated expression of six genes was confirmed by Northern blot analyses. The expression of chalcone synthase (CHS), flavanone 3-hydroxylase (F3H), and dihydroflavonol 4-reductase (DFR) genes showed a positive correlation with anthocyanin accumulation in UV-B-irradiated lettuce leaves; flavonoid 3',5'-hydroxylase (F3',5'H) and anthocyanidin synthase (ANS) were expressed continuously in both samples. These results indicated that the genes CHS, F3H, and DFR coincided with increases in anthocyanin accumulation during the red coloration of lettuce leaves. This study show a relationship between red coloration and the expression of up-regulated genes in lettuce. The subtractive cDNA library and EST database described in this study represent a valuable resource for further research for secondary metabolism in the vegetable crops.
Park
Jong-Sug
JS
Research Planning & Information Division, National Institute of Agricultural Biotechnology, Suwon, Korea. jongsug@rda.go.kr
Choung
Myoung-Gun
MG
Kim
Jung-Bong
JB
Hahn
Bum-Soo
BS
Kim
Jong-Bum
JB
Bae
Shin-Chul
SC
Roh
Kyung-Hee
KH
Kim
Yong-Hwan
YH
Cheon
Choong-Ill
CI
Sung
Mi-Kyung
MK
Cho
Kang-Jin
KJ
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D000872:Anthocyanins / Q000378:metabolism*; D015152:Blotting, Northern; D020224:Expressed Sequence Tags; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D015723:Gene Library; D017343:Genes, Plant; D018545:Lactuca / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays
D000872:Anthocyanins; D010940:Plant Proteins; D006899:Mixed Function Oxygenases; D000429:Alcohol Oxidoreductases; C056570:dihydroflavanol 4-reductase; C048797:flavanone 3-dioxygenase; D000217:Acyltransferases; C055296:6'-deoxychalcone synthase; C020141:flavanone synthetase