Metabolic pathways involved in cold acclimation identified by integrated analysis of metabolites and transcripts regulated by DREB1A and DREB2A.
DREB1A/CBF3 and DREB2A are transcription factors that specifically interact with a cis-acting dehydration-responsive element (DRE), which is involved in cold- and dehydration-responsive gene expression in Arabidopsis (Arabidopsis thaliana). Overexpression of DREB1A improves stress tolerance to both freezing and dehydration in transgenic plants. In contrast, overexpression of an active form of DREB2A results in significant stress tolerance to dehydration but only slight tolerance to freezing in transgenic plants. The downstream gene products for DREB1A and DREB2A are reported to have similar putative functions, but downstream genes encoding enzymes for carbohydrate metabolism are very different between DREB1A and DREB2A. We demonstrate that under cold and dehydration conditions, the expression of many genes encoding starch-degrading enzymes, sucrose metabolism enzymes, and sugar alcohol synthases changes dynamically; consequently, many kinds of monosaccharides, disaccharides, trisaccharides, and sugar alcohols accumulate in Arabidopsis. We also show that DREB1A overexpression can cause almost the same changes in these metabolic processes and that these changes seem to improve freezing and dehydration stress tolerance in transgenic plants. In contrast, DREB2A overexpression did not increase the level of any of these metabolites in transgenic plants. Strong freezing stress tolerance of the transgenic plants overexpressing DREB1A may depend on accumulation of these metabolites.
Maruyama
Kyonoshin
K
Biological Resources Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305-8686, Japan.
Takeda
Migiwa
M
Kidokoro
Satoshi
S
Yamada
Kohji
K
Sakuma
Yoh
Y
Urano
Kaoru
K
Fujita
Miki
M
Yoshiwara
Kyouko
K
Matsukura
Satoko
S
Morishita
Yoshihiko
Y
Sasaki
Ryosuke
R
Suzuki
Hideyuki
H
Saito
Kazuki
K
Shibata
Daisuke
D
Shinozaki
Kazuo
K
Yamaguchi-Shinozaki
Kazuko
K
D000064:Acclimatization / Q000235:genetics*; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D003681:Dehydration; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D055442:Metabolome / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013213:Starch / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; C114578:DREB1A protein, Arabidopsis; C114579:DREB2A protein, Arabidopsis; D012333:RNA, Messenger; D014157:Transcription Factors; D013395:Sucrose; D013213:Starch