Ethylene suppression of sugar-induced anthocyanin pigmentation in Arabidopsis.
Anthocyanin accumulation is regulated negatively by ethylene signaling and positively by sugar and light signaling. However, the antagonistic interactions underlying these signalings remain to be elucidated fully. We show that ethylene inhibits anthocyanin accumulation induced by sucrose (Suc) and light by suppressing the expression of transcription factors that positively regulate anthocyanin biosynthesis, including GLABRA3, TRANSPARENT TESTA8, and PRODUCTION OF ANTHOCYANIN PIGMENT1, while stimulating the concomitant expression of the negative R3-MYB regulator MYBL2. Genetic analyses show that the ethylene-mediated suppression of anthocyanin accumulation is dependent upon ethylene signaling components responsible for the triple response. Furthermore, these positive and negative signaling pathways appear to be under photosynthetic control. Suc and light induction of anthocyanin accumulation was almost fully inhibited in wild-type Arabidopsis (Arabidopsis thaliana) ecotype Columbia and ethylene (ethylene response1 [etr1-1]) and light (long hypocotyl1 [hy1], cryptochrome1/2, and hy5) signaling mutants treated with the photosynthetic electron transport inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea. The transcript level of the sugar transporter gene SUC1 was enhanced in ecotype Columbia treated with the ethylene-binding inhibitor silver and in etr1-1, ethylene insensitive2 (ein2-1), and ein3 ein3-like1 mutants. In contrast, 3-(3,4-dichlorophenyl)-1,1-dimethylurea treatment reduced SUC1 expression, which indicates strongly that SUC1 represents an integrator for signals provided by sugar, light, and ethylene. SUC1 mutations lowered accumulations of anthocyanin pigment, soluble sugar content, and ethylene production in response to Suc and light signals. These data demonstrate that the suppression of SUC1 expression by ethylene inhibits Suc-induced anthocyanin accumulation in the presence of light and, hence, fine-tunes anthocyanin homeostasis.
Jeong
Seok-Won
SW
Department of Biological Science and Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon, Korea.
Das
Prasanta Kumar
PK
Jeoung
Sae Chae
SC
Song
Ji-Young
JY
Lee
Hyun Kyoung
HK
Kim
Yeon-Ki
YK
Kim
Woo Jung
WJ
Park
Yong Il
YI
Yoo
Sang-Dong
SD
Choi
Sang-Bong
SB
Choi
Giltsu
G
Park
Youn-Il
YI
D000872:Anthocyanins / Q000096:biosynthesis*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D019295:Computational Biology; D005030:Ethylenes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008027:Light; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics; D015398:Signal Transduction
D000872:Anthocyanins; D005030:Ethylenes; D026901:Membrane Transport Proteins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D018749:RNA, Plant; C078729:sucrose transport protein, plant; C036216:ethylene