Arabidopsis ABA receptor RCAR1/PYL9 interacts with an R2R3-type MYB transcription factor, AtMYB44.
Abscisic acid (ABA) signaling plays important roles in plant growth, development and adaptation to various stresses. RCAR1/PYL9 has been known as a cytoplasm and nuclear ABA receptor in Arabidopsis. To obtain further insight into the regulatory mechanism of RCAR1/PYL9, a yeast two-hybrid approach was performed to screen for RCAR1/PYL9-interacting proteins and an R2R3-type MYB transcription factor, AtMYB44, was identified. The interaction between RCAR1/PYL9 and AtMYB44 was further confirmed by glutathione S-transferase (GST) pull-down and bimolecular fluorescence complementation (BiFC) assays. Gene expression analysis showed that AtMYB44 negatively regulated the expression of ABA-responsive gene RAB18, in contrast to the opposite role reported for RCAR1/PYL9. Competitive GST pull-down assay and analysis of phosphatase activity demonstrated that AtMYB44 and ABI1 competed for binding to RCAR1/PYL9 and thereby reduced the inhibitory effect of RCAR1/PYL9 on ABI1 phosphatase activity in the presence of ABA in vitro. Furthermore, transient activation assay in protoplasts revealed AtMYB44 probably also decreased RCAR1/PYL9-mediated inhibition of ABI1 activity in vivo. Taken together, our work provides a reasonable molecular mechanism of AtMYB44 in ABA signaling.
Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China. lidekuan198621@126.com.
Dekuan
D
Li
Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China. lyscholes@163.com.
Ying
Y
Li
Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China. liang.zhang113@gmail.com.
Liang
L
Zhang
Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China. ccandy1021@163.com.
Xiaoyu
X
Wang
Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China. zhaozhe89@126.com.
Zhe
Z
Zhao
Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China. scuzhiwen8508@126.com.
Zhiwen
Z
Tao
Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China. wangjianmei@scu.edu.cn.
Jianmei
J
Wang
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Biotechnology, Ministry of Agriculture, Beijing 100081, China. wjdsz@vip.sina.com.
Jin
J
Wang
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Biotechnology, Ministry of Agriculture, Beijing 100081, China. linmin57@vip.163.com.
Min
M
Lin
Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China. lixufeng0507@gmail.com.
Xufeng
X
Li
Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China. yangyi528@scu.edu.cn.
Yi
Y
Yang
D000040:Abscisic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D015398:Signal Transduction / Q000187:drug effects; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; C529221:At5g67300 protein, Arabidopsis; C540972:RCAR1 protein, Arabidopsis; D014157:Transcription Factors; D000040:Abscisic Acid; C087434:ABI1 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases