Stemar-13-ene synthase, a diterpene cyclase involved in the biosynthesis of the phytoalexin oryzalexin S in rice.
In suspension-cultured rice cells, diterpenoid phytoalexins are produced in response to exogenously applied elicitors. We isolated a cDNA encoding a diterpene cyclase, OsDTC2, from suspension-cultured rice cells treated with a chitin elicitor. The OsDTC2 cDNA was overexpressed in Escherichia coli as a fusion protein with glutathione S-transferase, and the recombinant OsDTC2 was indicated to function as stemar-13-ene synthase that converted syn-copalyl diphosphate to stemar-13-ene, a putative diterpene hydrocarbon precursor of the phytoalexin oryzalexin S. The level of OsDTC2 mRNA in suspension-cultured rice cells began to increase 3 h after addition of the elicitor and reached the maximum after 8 h. The expression of OsDTC2 was also induced in UV-irradiated rice leaves. In addition, we indicated that stemar-13-ene accumulated in the chitin-elicited suspension-cultured rice cells and the UV-irradiated rice leaves.
Nemoto
Tadahiro
T
Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Cho
Eun-Min
EM
Okada
Atsushi
A
Okada
Kazunori
K
Otomo
Kazuko
K
Kanno
Yuri
Y
Toyomasu
Tomonobu
T
Mitsuhashi
Wataru
W
Sassa
Takeshi
T
Minami
Eiichi
E
Shibuya
Naoto
N
Nishiyama
Makoto
M
Nojiri
Hideaki
H
Yamane
Hisakazu
H
D001483:Base Sequence; D019755:Carbon-Carbon Lyases / Q000378:metabolism*; D002478:Cells, Cultured; D017931:DNA Primers; D004224:Diterpenes / Q000378:metabolism*; D007700:Kinetics; D012275:Oryza / Q000201:enzymology*; D037121:Plant Lectins / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000235:genetics
D017931:DNA Primers; D004224:Diterpenes; D037121:Plant Lectins; D012333:RNA, Messenger; C488969:oryzalexin S; C099623:stemar-13-ene; D019755:Carbon-Carbon Lyases; C488968:stemar-13-ene synthase